%0 Generic %D 2018 %T Feature extraction and classification for pupillary images of rats %A Kalrmár, G %A Büki, A %A Kekesi, G %A Horváth, G %A Nyúl, LG %X

The investigation of the pupillary light reflex (PLR) is a well-known method to provide information about the functionality of the autonomic nervous system. Pupillometry, a non-invasive technique, was applied in our lab to study the schizophrenia-related PLR alterations in a new selectively bred rat substrain, named WISKET. The pupil responses to light impulses were recorded with an infrared camera; the videos were automatically processed and features were extracted. Besides the classical statistical analysis (ANOVA), feature selection and classification were applied to reveal the significant differences in the PLR parameters between the control and WISKET animals.

%B The 11th Conference of PhD Students in Computer Science. Volume of short papers. %C Szeged, Hungary %P 88--91 %U http://www.inf.u-szeged.hu/~cscs/pdf/cscs2018.pdf %9 Short Paper %0 Journal Article %J Autonomic Neuroscience: Basic and Clinical %D 2018 %T Impaired pupillary control in “schizophrenia-like” WISKET rats. Autonomic Neuroscience: Basic and Clinical. %A Büki, A %A Kalmár, G %A Kekesi, G %A Benedek, G %A Nyúl, LG %A Horváth, G %X

Patients with schizophrenia show impairments in autonomic regulation, including pupillomotor control. The aim of this study was to explore the changes of pupillary light reflex in a new substrain (WISKET) with several schizophrenia-like alterations.

Male WISKET rats housed individually (for four weeks) and treated with ketamine (for 3 × 5 days) after weaning and naive group-housed Wistar rats (controls) were involved in the study. The pupillary light reflex was studied in two series after sedation (diazepam) or anesthesia (chloral hydrate). Video recordings were evaluated with custom made video analyzer software.

Several significant changes were observed between the two groups: the initial and minimum pupil diameters were greater, the degree of the constriction was lower, and the flatness of the curve and the total duration of constriction were shorter in the sedated WISKET rats. No other pupillary parameters (latency, amplitude and redilation) showed significant alterations.

Chloral hydrate anesthesia prolonged the constriction and redilation processes compared to the sedated animals, and diminished the differences between the groups.

In conclusion, WISKET rats showed disturbances in the pupillary light reflex, suggesting a general shift of autonomic balance towards a sympathetic predominance. The results provide further evidence to support the validity of WISKET rats as a complex, chronic animal model of schizophrenia.

 

%B Autonomic Neuroscience: Basic and Clinical %I Elsevier %V 213 %P 34-42 %8 2018 September %G eng %9 Journal Article %& 34 %R https://doi.org/10.1016/j.autneu.2018.05.007 %0 Journal Article %J Acta Cybernetica %D 2017 %T Image processing-based automatic pupillometry on infrared videos. %A Kalmár, G %A Büki, A %A Kekesi, G %A Horváth, G %A Nyúl, LG %X

Pupillometry is a non-invasive technique that can be used to objectively characterize pathophysiological changes involving the pupillary reflex. It is essentially the measurement of the pupil diameter over time. Here, specially designed computer algorithms provide fast, reliable and reproducible solutions for the analysis. These methods use a priori information about the shape and color of the pupil. Our study focuses on measuring the diameter and dynamics of the pupils of rats with schizophrenia using videos recorded with a modified digital camera under infrared (IR) illumination. We developed a novel, robust method that measures the size of a pupil even under poor circumstances (noise, blur, reflections and occlusions). We compare our results with measurements obtained using manual annotation.

%B Acta Cybernetica %I Szegedi Tudományegyetem / University of Szeged %C Szeged %V 23 %P 599-613 %8 2017 %G eng %U http://cyber.bibl.u-szeged.hu/index.php/actcybern/article/view/29 %N 2 %9 Journal Article %& 599 %0 Journal Article %J ANNALS OF MATHEMATICS AND ARTIFICIAL INTELLIGENCE %D 2015 %T Binary image reconstruction from a small number of projections and the morphological skeleton %A Norbert Hantos %A Szabolcs Iván %A Péter Balázs %A Kálmán Palágyi %B ANNALS OF MATHEMATICS AND ARTIFICIAL INTELLIGENCE %I Springer %V 75 %P 195-216 %8 2015 %G eng %N 1 %9 Journal article %R 10.1007/s10472-014-9440-8 %0 Book Section %B Proceedings of the ACCV Workshop on Intelligent Mobile and Egocentric Vision (ACCV-IMEV), Lecture Notes in Computer Science %D 2015 %T Collaborative Mobile 3D Reconstruction of Urban Scenes %A Attila Tanacs %A András Majdik %A Levente Hajder %A Jozsef Molnar %A Zsolt Santa %A Zoltan Kato %E Chu-Song Chen %E Mohan Kankanhall %E Shang-Hong Lai %E Joo Hwee %B Proceedings of the ACCV Workshop on Intelligent Mobile and Egocentric Vision (ACCV-IMEV), Lecture Notes in Computer Science %I Springer %C Singapore %P 1-16 %8 Nov 2014 %G eng %9 Conference paper %0 Journal Article %J Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization %D 2015 %T Discrete tomographic reconstruction via adaptive weighting of gradient descents %A László Gábor Varga %A Péter Balázs %A Antal Nagy %X

Discrete tomography (DT) is a set of tools for reconstructing the inner structure of objects consisting of only few different homogeneous materials. We propose a new method for multivalued DT, which performs the reconstruction as an energy minimisation task. For this algorithm, we define an energy function that can mathematically formulate the reconstruction task, and design a novel optimisation process for approximating the minima of this energy function. We validate the algorithm by comparing its performance with other cutting-edge reconstruction algorithms from the literature. We show that our method can compete with the currently used reconstruction techniques and under certain circumstances (e.g. with a low number of projections, or when the projection data are affected by random noise) it can even outperform them.

%B Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization %I Taylor&Francis %V 3 %P 101-109 %8 Feb 2014 %G eng %N 2 %9 Journal article %& 101 %R DOI: 10.1080/21681163.2013.853624 %0 Book Section %B Proceedings of Combinatorial Image Analysis: 17th International Workshop, IWCIA 2015 %D 2015 %T Equivalent Sequential and Parallel Subiteration-Based Surface-Thinning Algorithms %A Kálmán Palágyi %A Gábor Németh %A Péter Kardos %E Reneta P Barneva %E Bhattacharya, B. B. %E Valentin E Brimkov %B Proceedings of Combinatorial Image Analysis: 17th International Workshop, IWCIA 2015 %S Lecture Notes in Computer Science %I Springer %C Calcutta, India %V 9448 %P 31-45 %8 Nov 2015 %@ 978-3-319-26144-7 %G eng %9 Conference paper %! LNCS %0 Journal Article %J PATTERN RECOGNITION %D 2015 %T Estimation of linear deformations of 2D and 3D fuzzy objects %A Attila Tanacs %A Joakim Lindbald %A Nataša Sladoje %A Zoltan Kato %X

Registration is a fundamental task in image processing, it is used to determine geometric correspondences between images taken at different times and/or from different viewpoints. Here we propose a general framework in n-dimensions to solve binary shape/object matching problems without the need of establishing additional point or other type of correspondences. The approach is based on generating and solving polynomial systems of equations. We also propose an extension which, provided that a suitable segmentation method can produce a fuzzy border representation, further increases the registration precision. Via numerous synthetic and real test we examine the different solution techniques of the polynomial systems of equations. We take into account a direct analytical, an iterative least-squares, and a combined method. Iterative and combined approaches produce the most precise results. Comparison is made against competing methods for rigid-body problems. Our method is orders of magnitude faster and is able to recover alignment regardless of the magnitude of the deformation compared to the narrow capture range of others. The applicability of the proposed methods is demonstrated on real X-ray images of hip replacement implants and 3D CT volumes of the pelvic area. Since the images must be parsed through only once, our approach is especially suitable for solving registration problems of large images.

%B PATTERN RECOGNITION %I Elsevier %V 48 %P 1387-1399 %8 Apr 2015 %G eng %N 4 %9 Journal Article %R 10.1016/j.patcog.2014.10.006 %0 Journal Article %J Acta Cybernetica %D 2015 %T Fast recognition of natural feature identifiers by a mobile phone %A Melinda Katona %A László G Nyúl %B Acta Cybernetica %I University of Szeged %C Szeged, Hungary %V 22 %P 101-116 %8 2015 %G eng %N 1 %9 Journal article %& 101 %0 Conference Paper %B A XXVIII. Neumann Kollokvium konferencia-kiadványa %D 2015 %T Időskori makula degeneráció kvantitatív jellemzése SD-OCT képek automatikus elemzésével %A László Gábor Varga %A Melinda Katona %A Tamás Grósz %A József Dombi %A Attila Kovács %A Rózsa Dégi %A László G Nyúl %B A XXVIII. Neumann Kollokvium konferencia-kiadványa %I Neumann János Számítógép-tudományi Társaság %C Veszprém, Hungary %P 43-48. %8 Nov 2015 %9 Conference paper %0 Journal Article %J Acta Cybernetica %D 2015 %T Improved QR Code Localization Using Boosted Cascade of Weak Classifiers %A Péter Bodnár %A László G Nyúl %B Acta Cybernetica %I University of Szeged %C Szeged, Hungary %V 22 %P 21-33 %8 2015 %G eng %N 1 %9 Journal article %& 21 %0 Conference Paper %B International Conference on Computer Vision Theory and Applications (VISAPP) %D 2015 %T Localization of Visual Codes using Fuzzy Inference System %A Péter Bodnár %A Nyúl, László Gábor %E J Braz %E S Battiato %E F Imai %B International Conference on Computer Vision Theory and Applications (VISAPP) %I SciTePress %C Berlin, Germany %P 345-352 %8 March 2015 %G eng %9 Conference paper %0 Journal Article %J Fundamenta Informaticae %D 2015 %T A Measure of Directional Convexity Inspired by Binary Tomography %A Péter Balázs %A Zoltán Ozsvár %A Tamás Sámuel Tasi %A László G Nyúl %X

Inspired by binary tomography, we present a measure of directional convexity of binary images combining various properties of the configuration of 0s and 1s in the binary image. The measure can be supported by proper theory, is easy to compute, and as shown in our experiments, behaves intuitively. The measure can be useful in numerous applications of digital image processing and pattern recognition, and especially in binary tomography. We show in detail an application of this latter one, by providing a novel reconstruction algorithm for almost hv-convex binary images. We also present experimental results and mention some of the possible generalizations of the measure.

%B Fundamenta Informaticae %V 141 %P 151-167 %8 Oct 2015 %G eng %N 2-3 %9 Journal article %& 151 %R 10.3233/FI-2015-1269 %0 Journal Article %J Clinical Oral Investigations %D 2015 %T Periosteal microcirculatory reactions in a zoledronate-induced osteonecrosis model of the jaw in rats %A Ágnes Janovszky %A Andrea Szabó %A Renáta Varga %A Dénes Garab %A Mihály Boros %A Csilla Mester %A Nikolett Beretka %A Tamás Zombori %A Hans-Peter Wiesmann %A Ricardo Bernhardt %A Imre Ocsovszki %A Péter Balázs %A József Piffkó %X

Objectives

Nitrogen-containing bisphosphonates induce osteonecrosis mostly in the jaw and less frequently in other bones. Because of the crucial role of periosteal perfusion in bone repair, we investigated zoledronate-induced microcirculatory reactions in the mandibular periosteum in comparison with those in the tibia in a clinically relevant model of bisphosphonate-induced medication-related osteonecrosis of the jaw (MRONJ).

Materials and methods

Sprague–Dawley rats were treated with zoledronate (ZOL; 80 i.v. μg/kg/week over 8 weeks) or saline vehicle. The first two right mandibular molar teeth were extracted after 3 weeks. Various systemic and local (periosteal) microcirculatory inflammatory parameters were examined by intravital videomicroscopy after 9 weeks.

Results

Gingival healing disorders (∼100 %) and MRONJ developed in 70 % of ZOL-treated cases but not after saline (shown by micro-CT). ZOL induced significantly higher degrees of periosteal leukocyte rolling and adhesion in the mandibular postcapillary venules (at both extraction and intact sites) than at the tibia. Leukocyte NADPH-oxidase activity was reduced; leukocyte CD11b and plasma TNF-alpha levels were unchanged.

Conclusion

Chronic ZOL treatment causes a distinct microcirculatory inflammatory reaction in the mandibular periosteum but not in the tibia. The local reaction in the absence of augmented systemic leukocyte inflammatory activity suggests that topically different, endothelium-specific changes may play a critical role in the pathogenesis of MRONJ.

Clinical relevance

This model permits for the first time to explore the microvascular processes in the mandibular periosteum after chronic ZOL treatment. This approach may contribute to a better understanding of the pathomechanism and the development of strategies to counteract bisphosphonate-induced side effects.

 

%B Clinical Oral Investigations %I Springer %V 19 %P 1279-1288 %8 July 2015 %G eng %N 6 %9 Journal article %& 1279 %R DOI 10.1007/s00784-014-1347-6 %0 Conference Paper %B Képfeldolgozók és Alakfelismerők Társaságának 10. országos konferenciája %D 2015 %T QR kód lokalizáció kaszkádolt gyenge osztályozók használatával %A Péter Bodnár %A László Gábor Nyúl %B Képfeldolgozók és Alakfelismerők Társaságának 10. országos konferenciája %C Kecskemét, Magyarország %P 712-721 %8 Jan 2015 %G hun %9 Conference paper %0 Journal Article %J Pattern Analysis and Machine Intelligence, IEEE Transactions on %D 2015 %T Realigning 2D and 3D Object Fragments without Correspondences %A Csaba Domokos %A Zoltan Kato %X

This paper addresses the problem of simultaneous estimation of different linear deformations, resulting in a global non-linear transformation, between an original object and its broken fragments. A general framework is proposed without using correspondences, where the solution of a polynomial system of equations directly provides the parameters of the alignment. We quantitatively evaluate the proposed algorithm on a large synthetic dataset containing 2D and 3D images, where linear (rigid-body and affine) transformations are considered. We also conduct an exhaustive analysis of the robustness against segmentation errors and the numerical stability of the proposed method. Moreover, we present experiments on 2D real images as well as on volumetric medical images.

 

%B Pattern Analysis and Machine Intelligence, IEEE Transactions on %I IEEE %V pp %P 1 %8 June 2015 %G eng %N 99 %9 Journal article %R 10.1109/TPAMI.2015.2450726 %0 Conference Paper %B Computational Vision and Medical Image Processing %D 2015 %T Semi-automatic tumor contouring method using PET and MRI medical images %A Szabolcs Urbán %A László Ruskó %A Antal Nagy %E Joao Manuel %E R S Tavares %E R M Natal Jorge %B Computational Vision and Medical Image Processing %I CRC Press - Taylor&Francis Group %C Tenerife, Spain %P 209-214 %8 Oct 2015 %@ 978-1-138-02926-2 %9 Conference paper %0 Conference Paper %B Képfeldolgozók és Alakfelismerők Társaságának 10. országos konferenciája %D 2015 %T Topology Preserving Reductions and Additions on the Triangular, Square, and Hexagonal Grids %A Péter Kardos %A Kálmán Palágyi %X

The Euclidean plane can be partitioned into three kinds of
regular polygons, which results in triangular, square and hexagonal grids.
While the topology of the square grid is well-established, less emphasis
is put on the remaining two regular sampling schemes. In this paper we
summarize the results of our research that aimed to give some general
characterizations of simple pixels and sufficient conditions for topology-
preserving operators in the mentioned grids.

%B Képfeldolgozók és Alakfelismerők Társaságának 10. országos konferenciája %C Kecskemét, Magyarország %P 588-600 %8 Jan 2015 %G eng %9 Conference paper %0 Conference Paper %B Image and Signal Processing and Analysis (ISPA), 2015 9th International Symposium on %D 2015 %T Topology-Preserving Equivalent Parallel and Sequential 4-Subiteration 2D Thinning Algorithms %A Kálmán Palágyi %A Gábor Németh %A Péter Kardos %E S Loncaric %E D Lerski %E H Eskola %E R Bregovic %X

Thinning is a frequently applied technique for extracting centerlines from 2D binary objects. Parallel thinning algorithms can remove a set of object points simultaneously, while sequential algorithms traverse the boundary of objects, and consider the actually visited single point for possible removal. Two thinning algorithms are called equivalent if they produce the same result for each input picture. This paper presents the very first pair of equivalent 2D sequential and parallel subiteration-based thinning algorithms. These algorithms can be implemented directly on a conventional sequential computer or on a parallel computing device. Both of them preserve topology for (8, 4) pictures sampled on the square grid.

%B Image and Signal Processing and Analysis (ISPA), 2015 9th International Symposium on %I IEEE %C Zagreb, Croatia %P 304-309 %8 2015 Sep %@ 978-1-4673-8032-4 %G english %9 Conference paper %R 10.1109/ISPA.2015.7306077 %0 Conference Paper %B A XXVIII. Neumann Kollokvium konferencia-kiadványa %D 2015 %T Újszülöttek monitorozása képfolyam elemzéssel %A Jozsef Nemeth %A András Bánhalmi %A László G Nyúl %A Márta Fidrich %A Zsolt Szkiva %A Péter Franczia %A Csaba Berezki %A Vilmos Bilicki %B A XXVIII. Neumann Kollokvium konferencia-kiadványa %I Neumann János Számítógép-tudományi Társaság %C Veszprém, Hungary %P 32-37 %8 Nov 2015 %@ 978-615-5036-10-1 %9 Conference paper %0 Conference Paper %B Képfeldolgozók és Alakfelismerők Társaságának 10. országos konferenciája %D 2015 %T Vékonyítás a végpont-megőrzés felülvizsgálatáva %A Gábor Németh %A Péter Kardos %A Kálmán Palágyi %X

A vékonyítás mint iteratív objektum redukció gyakran alkalmazott
vázkijelölo módszer. A legtöbb létezo vékonyító algoritmus végpontok - vagyis releváns geometriai információt hordozó objektumpontok - megorzésével biztosítja azt, hogy ne törlodjenek az objektumok alakját reprezentáló fontos részletek. Ennek a megközelítésnek hátránya, hogy számos nemkívánatos vázágat eredményezhet. Ebben a cikkben egy olyan módszert mutatunk be, amellyel jelentosen csökkentheto a hamis vázágak száma. Ráadásul az itt bemutatott megközelítés tetszoleges végpont-megorzo 2D vékonyító algoritmusban alkalmazható.

%B Képfeldolgozók és Alakfelismerők Társaságának 10. országos konferenciája %C Kecskemét, Magyarország %P 578-587 %8 Jan 2015 %G hun %9 Conference paper %0 Conference Paper %B Képfeldolgozók és Alakfelismerők Társaságának 10. országos konferenciája. %D 2015 %T Vizuális kódok lokalizációja mély egyenirányított neurális háló használatával %A Péter Bodnár %A László Gábor Nyúl %A Tamás Grósz %A László Tóth %B Képfeldolgozók és Alakfelismerők Társaságának 10. országos konferenciája. %C Kecskemét, Magyarország %P 546-561 %8 Jan 2015 %G hun %9 Conference paper %0 Conference Paper %B Képfeldolgozók és Alakfelismerők Társaságának 10. országos konferenciája %D 2015 %T Vonalkódok és természetes vizuális azonosítók felismerése valós időben %A Melinda Katona %A László Gábor Nyúl %B Képfeldolgozók és Alakfelismerők Társaságának 10. országos konferenciája %C Kecskemét, Magyarország %P 562-577 %8 Jan 2015 %G hun %9 Conference paper %0 Conference Paper %B International Conference on Digital Image Computing: Techniques and Applications (DICTA) %D 2014 %T 3D Reconstruction of Planar Patches Seen by Omnidirectional Cameras %A Jozsef Molnar %A Robert Frohlich %A Chetverikov Dmitrij %A Zoltan Kato %E Abdesselam Bouzerdoum %E Lei Wang %E Philip Ogunbona %E Wanqing Li %E Son Lam Phung %B International Conference on Digital Image Computing: Techniques and Applications (DICTA) %I IEEE %C Wollongong, Australia %P 1-8 %G eng %9 Conference paper %0 Book Section %B Proceedings of the ACCV Workshop on Big Data in 3D Computer Vision (ACCV-BigData3DCV) %D 2014 %T 3D Reconstruction of Planar Surface Patches: A Direct Solution %A Jozsef Molnar %A Rui Huang %A Zoltan Kato %E Jian Zhang %E Mohammed Bennamoun %E Fatih Porikli %B Proceedings of the ACCV Workshop on Big Data in 3D Computer Vision (ACCV-BigData3DCV) %I Springer %C Singapore, Szingapúr %P 1-8. %8 Nov 2014 %G eng %9 Conference paper %0 Conference Paper %B International Conference on Pattern Recognition (ICPR) %D 2014 %T Affine Alignment of Occluded Shapes %A Zsolt Santa %A Zoltan Kato %E Michael Felsberg %B International Conference on Pattern Recognition (ICPR) %I IEEE %C Stockholm, Svédország %P 2155-2160 %8 Aug 2014 %@ 978-4-9906441-0-9 %9 Conference paper %0 Journal Article %J ANTIMICROBIAL AGENTS AND CHEMOTHERAPY %D 2014 %T Application of DNA chip scanning technology for the automatic detection of Chlamydia trachomatis and Chlamydia pneumoniae inclusions. %A Anita Bogdanov %A Valéria Endrész %A Szabolcs Urbán %A Ildikó Lantos %A Judit Deák %A Katalin Burián %A K Önder %A Ferhan Ayaydin %A Péter Balázs %A Dezső P Virók %X

Chlamydiae are obligate intracellular bacteria that propagate in the inclusion, a specific niche inside the host cell. The standard method for counting chlamydiae is the immunofluorescent staining and manual counting of chlamydial inclusions. High or medium throughput estimation of the reduction in chlamydia inclusions should be the basis of testing antichlamydial compounds and other drugs that positively or negatively influence chlamydial growth, yet low-throughput manual counting is the common approach. To overcome the time-consuming and subjective manual counting we developed an automatic inclusion counting system based on a commercially available DNA chip scanner. Fluorescently labeled inclusions are detected by the scanner, and the image is processed by ChlamyCount, a custom plugin of the ImageJ software environment. ChlamyCount was able to measure the inclusion counts over a one log dynamic range with high correlation to the theoretical counts. ChlamyCount was capable of accurately determining the minimum inhibitory concentration of the novel antimicrobial compound PCC00213 and the already known antichlamydial antibiotics moxifloxacin and tetracycline. ChlamyCount was also able to measure the chlamydial growth altering effect of drugs that influence host-bacterium interaction such as interferon-gamma, DEAE-dextran and cycloheximide. ChlamyCount is an easily adaptable system for testing antichlamydial antimicrobials and other compounds that influence Chlamydia-host interactions.

%B ANTIMICROBIAL AGENTS AND CHEMOTHERAPY %V 58 %P 405 - 413 %8 2014 %@ 0066-4804 %G eng %N 1 %9 Journal article %! ANTIMICROB AGENTS CH %0 Journal Article %J HIRADÁSTECHNIKA %D 2014 %T Automatikus azonosítás és hitelesítés vizuális kódokkal %A Melinda Katona %A László Gábor Nyúl %B HIRADÁSTECHNIKA %V 69 %P 40-47 %G eng %N 1 %9 Journal Article %) hun %0 Generic %D 2014 %T Eliminating switching components in binary matrices %A Norbert Hantos %A Péter Balázs %B Proceedings of the 9th Conference of PhD Students in Computer Science (CSCS'14) %I University of Szeged %C Szeged, Hungary %P 21 %G eng %9 Abstract %0 Book Section %B Combinatorial Image Analysis %D 2014 %T Equivalent 2D sequential and parallel thinning %A Kálmán Palágyi %E Reneta P Barneva %E Valentin E Brimkov %E Josef Šlapal %B Combinatorial Image Analysis %I Springer %C Brno, Czech Republic %P 91 - 100 %8 May 2014 %G eng %9 Conference paper %0 Conference Paper %B International Conference on Digital Image Computing: Techniques and Applications (DICTA) %D 2014 %T Establishing Correspondences between Planar Image Patches %A Attila Tanacs %A András Majdik %A Jozsef Molnar %A Atul Rai %A Zoltan Kato %E Abdesselam Bouzerdoum %E Lei Wang %E Philip Ogunbona %E Wanqing Li %E Son Lam Phung %B International Conference on Digital Image Computing: Techniques and Applications (DICTA) %I IEEE %C Wollongong, Australia %P 1-7 %8 2014 %G eng %9 Conference paper %0 Book Section %B Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications: 19th Iberoamerican Congress (CIARP) %D 2014 %T Fast Heuristics for Eliminating Switching Components in Binary Matrices by 0-1 Flips %A Norbert Hantos %A Péter Balázs %E E. Bayro-Corrochano %E E. Hancock %X

Switching components are special patterns in binary matrices that play an essential role in many image processing and pattern analysis tasks. Finding the minimal number of 0s that must be switched to 1s in order to eliminate all switching components is an NP-complete problem. We present two novel-type heuristics for the above problems and show via experiments that they outperform the formerly proposed ones, both in optimality and in running time.

%B Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications: 19th Iberoamerican Congress (CIARP) %S LNCS %I Springer %C Puerto Vallarta, Mexico %P 62-69 %8 2014 %@ 978-3-319-12567-1 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-319-12568-8_8 %0 Generic %D 2014 %T Fast recognition of natural feature identifiers by a mobile phone %A Melinda Katona %A László Gábor Nyúl %B Conference of PhD Students in Computer Science. Volume of extended abstracts %I Institute of Informatics, University of Szeged %C Szeged %P 26 %8 June 2014 %G eng %9 Abstract %0 Book Section %B Informatika a felsőoktatásban 2014 %D 2014 %T Képfeldolgozás a szegedi informatikus-képzésben %A Péter Balázs %A Endre Katona %A Zoltan Kato %A Antal Nagy %A Gábor Németh %A László Gábor Nyúl %A Kálmán Palágyi %A Attila Tanacs %A László Gábor Varga %E Roland Kunkli %E Ildikó Papp %E Edéné Rutkovszky %B Informatika a felsőoktatásban 2014 %I University of Debrecen %C Debrecen, Hungary %P 667-675 %8 2014 %G hun %9 Conference paper %0 Journal Article %J COMPUTER VISION AND IMAGE UNDERSTANDING %D 2014 %T Local and global uncertainty in binary tomographic reconstruction %A László Gábor Varga %A László Gábor Nyúl %A Antal Nagy %A Péter Balázs %X

In binary tomography the goal is to reconstruct the innerstructure of homogeneous objects from their projections. This is usually required from a low number of projections, which are also likely to be affected by noise and measurement errors. In general, the distorted and incomplete projection data holds insufficient information for the correct reconstruction of the original object. In this paper, we describe two methods for approximating the local uncertainty of the reconstructions, i.e., identifying how the information stored in the projections determine each part of the reconstructed image. These methods can measure the uncertainty of the reconstruction without any knowledge from the original object itself. Moreover, we provide a global uncertainty measure that can assess the information content of a projection set and predict the error to be expected in the reconstruction of a homogeneous object. We also give an experimental evaluation of our proposed methods, mention some of their possible applications, and describe how the uncertainty measure can be used to improve the performance of the DART reconstruction algorithm.

%B COMPUTER VISION AND IMAGE UNDERSTANDING %8 2014 %@ 1077-3142 %G eng %9 Journal article %! COMPUT VIS IMAGE UND %R 10.1016/j.cviu.2014.05.006 %0 Book Section %B International Conference on Informatics in Control, Automation and Robotics (ICINCO) %D 2014 %T Localization of Visual Codes in the DCT Domain Using Deep Rectier Neural Networks %A Péter Bodnár %A Tamás Grósz %A László Tóth %A László Gábor Nyúl %E Joaquim Filipe %E Oleg Gusikhin %E Kurosh Madani %E Jurek Sasiadek %B International Conference on Informatics in Control, Automation and Robotics (ICINCO) %I SCITEPRESS %C Setúbal %8 2014 %G eng %9 Conference paper %0 Book Section %B Orvosi Informatika 2014: A XXVII. Neumann Kollokvium konferencia-kiadványa %D 2014 %T Orvosi képfeldolgozás az SZTE Képfeldolgozás és Számítógépes Grafika Tanszéken %A László Gábor Nyúl %B Orvosi Informatika 2014: A XXVII. Neumann Kollokvium konferencia-kiadványa %I Pannon Egyetem, Veszprém %C Szeged, Hungary %P 119-122 %@ 978-963-396-040-0 %0 Book Section %B Image Analysis and Recognition (ICIAR) %D 2014 %T QR Code Localization Using Boosted Cascade of Weak Classifiers %A Péter Bodnár %A László Gábor Nyúl %E Mohamed Kamel %E Aurélio Campilho %X

Usage of computer-readable visual codes became common in oureveryday life at industrial environments and private use. The reading process of visual codes consists of two steps: localization and data decoding. Unsupervised localization is desirable at industrial setups and for visually impaired people. This paper examines localization efficiency of cascade classifiers using Haar-like features, Local Binary Patterns and Histograms of Oriented Gradients, trained for the finder patterns of QR codes and for the whole code region as well, and proposes improvements in post-processing.

%B Image Analysis and Recognition (ICIAR) %S Lecture Notes In Computer Science %I Springer-Verlag %C Vilamura, Portugal %8 Oct 2014 %G eng %9 Conference paper %0 Generic %D 2014 %T QR Code Localization Using Boosted Cascade of Weak Classifiers %A Péter Bodnár %A László Gábor Nyúl %B Conference of PhD Students in Computer Science. Volume of Extended Abstracts %I Institute of Informatics, University of Szeged %C Szeged %P 6 - 7 %8 June 2014 %G eng %9 Abstract %0 Book Section %B International Workshop on Machine Learning for Signal Processing %D 2014 %T QR code localization using deep neural networks %A Tamás Grósz %A Péter Bodnár %A László Tóth %A László Gábor Nyúl %E Mboup Mamadou %E Adali Tülay %E Eric Moreau %E Jan Larsen %E Kevin Guelton %B International Workshop on Machine Learning for Signal Processing %I IEEE %C Sep 2014, Reims, France %8 Sep 2014 %G eng %9 Conference paper %0 Generic %D 2014 %T Reconstruction of hv-convex binary matrices from horizontal and vertical projections based on simulated annealing %A Zoltán Ozsvár %A Péter Balázs %B Proceedings of the 9th Conference of PhD Students in Computer Science (CSCS'14) %I University of Szeged %C Szeged, Hungary %P 50 %G eng %9 Abstract %0 Book Section %B Combinatorial Image Analysis %D 2014 %T Smoothing Filters in the DART Algorithm %A Antal Nagy %E Reneta P Barneva %E Valentin E Brimkov %E Josef Šlapal %B Combinatorial Image Analysis %I Springer %C May 2014, Brno, Czech Republic %P 224 - 237 %8 May 2014 %G eng %U http://link.springer.com/chapter/10.1007%2F978-3-319-07148-0_20 %9 Conference paper %R 10.1007/978-3-319-07148-0_20 %0 Book Section %B Combinatorial Image Analysis %D 2014 %T Sufficient conditions for general 2D operators to preserve topology %A Péter Kardos %A Kálmán Palágyi %E Reneta P Barneva %E Valentin E Brimkov %E Josef Šlapal %X

An important requirement for various applications of binary image processing is to preserve topology. This issue has been earlier studied for two special types of image operators, namely, reductions and additions, and there have been some sufficient conditions proposed for them. In this paper, as an extension of those earlier results, we give novel sufficient criteria for general operators working on 2D pictures.

 

%B Combinatorial Image Analysis %S Lecture Notes in Computer Science %I Springer %C May 2014, Brno, Czech Republic %V 8466 %P 101 - 112 %8 2014 %@ 978-3-319-07147-3 %G eng %U http://dx.doi.org/10.1007/978-3-319-07148-0_10 %9 Conference paper %! Conference Paper %R 10.1007/978-3-319-07148-0_10 %0 Conference Paper %B The 8th International Workshop on Semantic Evaluation (SemEval 2014) %D 2014 %T SZTE-NLP: Clinical Text Analysis with Named Entity Recognition %A Melinda Katona %A Richárd Farkas %E Preslav Nakov %E Torsten Zesch %B The 8th International Workshop on Semantic Evaluation (SemEval 2014) %I ACL %C Dublin, Ireland %P 615-618 %8 Aug 2014 %@ 978-1-941643-24-2 %G eng %9 Conference paper %0 Book Section %B CLEF2014 Working Notes: Working Notes for CLEF 2014 Conference %D 2014 %T Wlab of University of Szeged at ImageCLEF 2014 Plant Identification Task %A András Bánhalmi %A Dénes Paczolay %A Vilmos Bilicki %A László Gábor Nyúl %A Árpád Sárosi %E Linda Cappellato %E Nicola Ferro %E Martin Halvey %E Wessel Kraai %B CLEF2014 Working Notes: Working Notes for CLEF 2014 Conference %I CEUR-WS %C Sheffield, UK %V 1180 %P 685-692 %8 Sep %G eng %9 Conference paper %0 Conference Proceedings %D 2014 %T X. Magyar Számítógépes Nyelvészeti Konferencia %E Attila Tanacs %E Viktor Varga %E Veronika Vincze %I Szegedi Tudományegyetem Informatikai Tanszékcsoport %C Szeged %8 2014 %G eng %U http://www.inf.u-szeged.hu/rgai/mszny2014/ %9 Conference proceedings %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %D 2013 %T 2D és 3D bináris objektumok lineáris deformáció-becslésének numerikus megoldási lehetőségei %A Attila Tanacs %A Joakim Lindblad %A Nataša Sladoje %A Zoltan Kato %E László Czúni %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %I NJSZT-KÉPAF %C Veszprém %P 526 - 541 %8 Jan 2013 %G eng %9 Conference paper %0 Journal Article %J ACTA CYBERNETICA-SZEGED %D 2013 %T Barcode detection using local analysis, mathematical morphology, and clustering %A Péter Bodnár %A László Gábor Nyúl %X

Barcode detection is required in a wide range of real-lifeapplications. Imaging conditions and techniques vary considerably and each application has its own requirements for detection speed and accuracy. In our earlier works we built barcode detectors using morphological operations and uniform partitioning with several approaches and showed their behaviour on a set of test images. In this work, we extend those ideas with clustering, contrast measuring, distance transformation and probabilistic Hough transformation.

%B ACTA CYBERNETICA-SZEGED %V 21 %P 21 - 35 %8 2013 %@ 0324-721X %G eng %N 1 %9 Journal article %! ACTA CYBERN-SZEGED %0 Conference Paper %B IASTED International Conference on Computer Graphics and Imaging (CGIM) %D 2013 %T Barcode detection with uniform partitioning and distance transformation %A Péter Bodnár %A László Gábor Nyúl %E L Linsen %X

Barcode detection is required in a wide range of real-lifeapplications. Imaging conditions and techniques vary considerably and each application has its own requirements for detection speed and accuracy. In our earlier works we used uniform partitioning with several approaches for detection of various types of 1D and 2D barcodes and showed their behaviour on a set of test images. In this work, we extend the partitioning idea and replace scan-line based methods with distance transformation to improve accuracy.

%B IASTED International Conference on Computer Graphics and Imaging (CGIM) %I IASTED - Acta Press %C Innsbruck, Austria %P 48 - 53 %8 Feb 2013 %G eng %U http://www.actapress.com/PaperInfo.aspx?paperId=454988 %9 Conference paper %R 10.2316/P.2013.797-022 %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %D 2013 %T A comparison of heuristics for reconstructing hv-convex binary matrices from horizontal and vertical projections %A Zoltán Ozsvár %A Péter Balázs %E László Czúni %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %I NJSZT-KÉPAF %C Veszprém %P 168 - 181 %8 Jan 2013 %G eng %9 Conference paper %0 Journal Article %J DISCRETE APPLIED MATHEMATICS %D 2013 %T Complexity results for reconstructing binary images with disjoint components from horizontal and vertical projections %A Péter Balázs %B DISCRETE APPLIED MATHEMATICS %V 161 %P 2224 - 2235 %8 2013 %@ 0166-218X %G eng %9 Journal article %! DISCRETE APPL MATH %0 Journal Article %J ACTA CYBERNETICA-SZEGED %D 2013 %T Conference of PhD Students in Computer Science %A Kálmán Palágyi %B ACTA CYBERNETICA-SZEGED %V 21 %P 1 - 3 %8 2013 %@ 0324-721X %G eng %N 1 %9 Journal article %! ACTA CYBERN-SZEGED %0 Conference Paper %B IEEE Conference on Computer Vision and Pattern Recognition (CVPR) %D 2013 %T Correspondence-less non-rigid registration of triangular surface meshes %A Zsolt Santa %A Zoltan Kato %X

A novel correspondence-less approach is proposed to find a thin plate spline map between a pair of deformable 3D objects represented by triangular surface meshes. The proposed method works without landmark extraction and feature correspondences. The aligning transformation is found simply by solving a system of nonlinear equations. Each equation is generated by integrating a nonlinear function over the object's domains. We derive recursive formulas for the efficient computation of these integrals. Based on a series of comparative tests on a large synthetic dataset, our triangular mesh-based algorithm outperforms state of the art methods both in terms of computing time and accuracy. The applicability of the proposed approach has been demonstrated on the registration of 3D lung CT volumes. © 2013 IEEE.

%B IEEE Conference on Computer Vision and Pattern Recognition (CVPR) %I IEEE %C Portland, OR, USA %P 2275 - 2282 %8 June 2013 %G eng %9 Conference paper %R 10.1109/CVPR.2013.295 %0 Book Section %B Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications %D 2013 %T Deletion Rules for Equivalent Sequential and Parallel Reductions %A Kálmán Palágyi %E Jose Ruiz-Shulcloper %E Gabriella Sanniti di Baja %X

A reduction operator transforms a binary picture only by changing some black points to white ones, which is referred to as deletion. Sequential reductions may delete just one point at a time, while parallel reductions can alter a set of points simultaneously. Two reductions are called equivalent if they produce the same result for each input picture. This work lays a bridge between the parallel and the sequential strategies. A class of deletion rules are proposed that provide 2D parallel reductions being equivalent to sequential reductions. Some new sufficient conditions for topology-preserving parallel reductions are also reported.

%B Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications %S Lecture Notes in Computer Science %I Springer %C Berlin; Heidelberg %P 17 - 24 %8 Nov 2013 %@ 978-3-642-41821-1 %G eng %U http://link.springer.com/chapter/10.1007%2F978-3-642-41822-8_3 %9 Conference paper %! Conference Paper %R 10.1007/978-3-642-41822-8_3 %0 Book Section %B Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications %D 2013 %T Directional Convexity Measure for Binary Tomography %A Tamás Sámuel Tasi %A László Gábor Nyúl %A Péter Balázs %E Gabriella Sanniti di Baja %E Jose Ruiz-Shulcloper %X

There is an increasing demand for a new measure of convexity fordiscrete sets for various applications. For example, the well- known measures for h-, v-, and hv-convexity of discrete sets in binary tomography pose rigorous criteria to be satisfied. Currently, there is no commonly accepted, unified view on what type of discrete sets should be considered nearly hv-convex, or to what extent a given discrete set can be considered convex, in case it does not satisfy the strict conditions. We propose a novel directional convexity measure for discrete sets based on various properties of the configuration of 0s and 1s in the set. It can be supported by proper theory, is easy to compute, and according to our experiments, it behaves intuitively. We expect it to become a useful alternative to other convexity measures in situations where the classical definitions cannot be used.

%B Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications %I Springer Verlag %C Berlin; Heidelberg %P 9 - 16 %8 2013 %G eng %U http://link.springer.com/chapter/10.1007%2F978-3-642-41827-3_2 %9 Conference paper %R 10.1007/978-3-642-41827-3_2 %0 Journal Article %J COMPUTER VISION AND IMAGE UNDERSTANDING %D 2013 %T Dynamic angle selection in binary tomography %A Joost K Batenburg %A Willem Jan Palenstijn %A Péter Balázs %A Jan Sijbers %X

In this paper, we present an algorithm for the dynamic selection of projection angles in binary tomography. Based on the information present in projections that have already been measured, a new projection angle is computed, which aims to maximize the information gained by adding this projection to the set of measurements. The optimization model used for angle selection is based on a characterization of solutions of the binary reconstruction problem, and a related definition of information gain. From this formal model, an algorithm is obtained by several approximation steps. Results from a series of simulation experiments demonstrate that the proposed angle selection scheme is indeed capable of finding angles for which the reconstructed image is much more accurate than for the standard angle selection scheme. © 2012 Elsevier Inc. All rights reserved.

%B COMPUTER VISION AND IMAGE UNDERSTANDING %V 117 %P 306 - 318 %8 2013 %@ 1077-3142 %G eng %N 4 %9 Journal article %! COMPUT VIS IMAGE UND %R 10.1016/j.cviu.2012.07.005 %0 Book Section %B Mathematical Morphology and Its Applications to Signal and Image Processing %D 2013 %T Efficient 1D and 2D barcode detection using mathematical morphology %A Melinda Katona %A László Gábor Nyúl %E Chris L Luengo %E Gunilla Borgefors %E Robin Strand %X

Barcode technology is essential in automatic identification,and is used in a wide range of real-time applications. Different code types and applications impose special problems, so there is a continuous need for solutions with improved performance. Several methods exist for code localization, that are well characterized by accuracy and speed. Particularly, high-speed processing places need reliable automatic barcode localization, e.g. conveyor belts and automated production, where missed detections cause loss of profit. Our goal is to detect automatically, rapidly and accurately the barcode location with the help of extracted image features. We propose a new algorithm variant, that outperforms in both accuracy and efficiency other detectors found in the literature using similar ideas, and also improves on the detection performance in detecting 2D codes compared to our previous algorithm.

%B Mathematical Morphology and Its Applications to Signal and Image Processing %I Springer-Verlag %C Berlin; Heidelberg %P 464 - 475 %8 May 2013 %G eng %9 Conference paper %0 Book Section %B Proceedings of International Conference on Digital Image Computing: Techniques and Applications (DICTA) %D 2013 %T Elastic Registration of 3D Deformable Objects %A Zsolt Santa %A Zoltan Kato %E Geoff West %E Péter Kövesi %X

A novel correspondence-less approach is proposed to find a non-linear aligning transformation between a pair of deformable 3D objects. Herein, we consider a polynomial deformation model, but our framework can be easily adapted to other common deformations. The basic idea of the proposed method is to set up a system of nonlinear equations whose solution directly provides the parameters of the aligning transformation. Each equation is generated by integrating a nonlinear function over the object's domains. Thus the number of equations is determined by the number of adopted nonlinear functions yielding a flexible mechanism to generate sufficiently many equations. While classical approaches would establish correspondences between the shapes, our method works without landmarks. The efficiency of the proposed approach has been demonstrated on a large synthetic dataset as well as in the context of medical image registration.

%B Proceedings of International Conference on Digital Image Computing: Techniques and Applications (DICTA) %I IEEE %C New York %P 1 - 7 %8 Nov 2013 %G eng %U http://www.inf.u-szeged.hu/~kato/papers/dicta2012.pdf %9 Conference paper %R 10.1109/DICTA.2012.6411674 %0 Journal Article %J ACTA CYBERNETICA-SZEGED %D 2013 %T An empirical study of reconstructing hv-convex binary matrices from horizontal and vertical projections %A Zoltán Ozsvár %A Péter Balázs %X

The reconstruction of hv-convex binary matrices (or equivalently, binary images) from their horizontal and vertical projections is proved to be NP-hard. In this paper we take a closer look at the difficulty of the problem. We investigate different heuristic reconstruction algorithms of the class, and compare them from the viewpoint of running-time and reconstruction quality. Using a large set of test images of different sizes and with varying number of components, we show that the reconstruction quality can depend not only on the size of the image, but on the number and location of its components, too. We also reveal that the reconstruction time can also be affected by the number of the so-called switching components present in the image.

 

%B ACTA CYBERNETICA-SZEGED %V 21 %P 149 - 163 %8 2013 %@ 0324-721X %G eng %9 Journal article %! ACTA CYBERN-SZEGED %0 Book Section %B Proceedings of the International Symposium on Image and Signal Processing and Analysis (ISPA) %D 2013 %T Evaluation of Point Matching Methods for Wide-baseline Stereo Correspondence on Mobile Platforms %A Endre Juhász %A Attila Tanacs %A Zoltan Kato %E Giovanni Ramponi %E Sven Lončarić %E Alberto Carini %E Karen Egiazarian %X

Wide-baseline stereo matching is a common problem of computer vision. By the explosion of smartphones equipped with camera modules, many classical computer vision solutions have been adapted to such platforms. Considering the widespread use of various networking options for mobile phones, one can consider a set of smart phones as an ad-hoc camera network, where each camera is equipped with a more and more powerful computing engine in addition to a limited bandwidth communication with other devices. Therefore the performance of classical vision algorithms in a collaborative mobile environment is of particular interest. In such a scenario we expect that the images are taken almost simultaneously but from different viewpoints, implying that the camera poses are significantly different but lighting conditions are the same. In this work, we provide quantitative comparison of the most important keypoint detectors and descriptors in the context of wide baseline stereo matching. We found that for resolution of 2 megapixels images the current mobile hardware is capable of providing results efficiently.

 

%B Proceedings of the International Symposium on Image and Signal Processing and Analysis (ISPA) %I IEEE %C Trieste %P 806 - 811 %8 Sep 2013 %G eng %9 Conference paper %R 10.1109/ISPA.2013.6703848 %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %D 2013 %T Gépkocsi felismerés elölnézeti képek alapján %A Viktor Varjas %A Attila Tanacs %E László Czúni %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %I NJSZT-KÉPAF %C Veszprém %P 294 - 308 %8 Jan 2013 %G eng %9 Conference paper %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %D 2013 %T Gradiens módszerek automatikus súlyozásán alapuló diszkrét tomográfiai eljárás %A László Gábor Varga %A Péter Balázs %A Antal Nagy %E László Czúni %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %I NJSZT-KÉPAF %C Veszprém %P 210 - 223 %8 Jan 2013 %G eng %9 Conference paper %0 Conference Paper %B Képfeldolgozók és Alakfelismerők IX. Konferenciája %D 2013 %T Háromszöghálók nemlineáris illesztése megfeleltetések nélkül %A Sánta Zsolt %A Kató Zoltán %B Képfeldolgozók és Alakfelismerők IX. Konferenciája %P 224-239 %9 Conference paper %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %D 2013 %T Improved 1D and 2D barcode detection with morphological operations %A Melinda Katona %A László Gábor Nyúl %E László Czúni %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %I NJSZT-KÉPAF %C Veszprém %P 309 - 324 %8 Jan 2013 %G eng %9 Conference paper %0 Book Section %B Proceedings of International Joint Conference on Computer Vision, Imaging and Computer Graphics - Theory and Applications (Revised Selected Papers) %D 2013 %T Linear and nonlinear shape alignment without correspondences %A Zoltan Kato %E Paul Richard %E Gabriela Csurka %X

We consider the estimation of diffeomorphic deformations aligning a known binary shape and its distorted observation. The classical solution consists in extracting landmarks, establishing correspondences and then the aligning transformation is obtained via a complex optimization procedure. Herein we present an alternative solution which works without landmark correspondences, is independent of the magnitude of transformation, easy to implement, and has a linear time complexity. The proposed universal framework is capable of recovering linear as well as nonlinear deformations.

 

%B Proceedings of International Joint Conference on Computer Vision, Imaging and Computer Graphics - Theory and Applications (Revised Selected Papers) %S Communications in Computer and Information Science %I Springer Verlag %C Berlin; Heidelberg; New York; London; Paris; Tokyo %P 3 - 17 %8 Feb 2013 %G eng %U http://www.inf.u-szeged.hu/~kato/papers/visapp2012.pdf %9 Conference paper %R 10.1007/978-3-642-38241-3_1 %0 Book Section %B Proceedings of the IASTED International Conference on Signal Processing, Pattern Recognition and Applications (SPPRA 2013) %D 2013 %T Local uncertainty in binary tomographic reconstruction %A László Gábor Varga %A László Gábor Nyúl %A Antal Nagy %A Péter Balázs %E Martin Kampel %X

We describe a new approach for the uncertainty problem arisingin the field of discrete tomography, when the low number of projections does not hold enough information for an accurate, and reliable reconstruction. In this case the lack of information results in uncertain parts on the reconstructed image which are not determined by the projections and cannot be reliably reconstructed without additional information. We provide a method that can approximate this local uncertainty of reconstructions, and show how each pixel of the reconstructed image is determined by a set of given projections. We also give experimental results for validating our approach.

%B Proceedings of the IASTED International Conference on Signal Processing, Pattern Recognition and Applications (SPPRA 2013) %I IASTED - Acta Press %C Calgary %P 490 - 496 %8 Feb 2013 %G eng %9 Conference paper %R 10.2316/P.2013.798-067 %0 Book Section %B Image Analysis and Recognition (ICIAR) %D 2013 %T A Novel Method for Barcode Localization in Image Domain %A Péter Bodnár %A László Gábor Nyúl %E Mohamed Kamel %E Aurélio Campilho %X

Barcode localization is an essential step of the barcode readingprocess. For industrial environments, having high-resolution cameras and eventful scenarios, fast and reliable localization is crucial. Images acquired in those setups have limited parameters, however, they vary at each application. In earlier works we have already presented various barcode features to track for localization process. In this paper, we present a novel approach for fast barcode localization using a limited set of pixels in image domain.

%B Image Analysis and Recognition (ICIAR) %S Lecture Notes in Computer Science %I Springer-Verlag %C Berlin %P 189 - 196 %8 June 2013 %G eng %9 Conference paper %R 10.1007/978-3-642-39094-4_22 %0 Book Section %B Advances in Visual Computing %D 2013 %T Parallel 3D 12-Subiteration Thinning Algorithms Based on Isthmuses %A Kálmán Palágyi %E George Bebis %X

Thinning is an iterative object reduction to obtain skeleton-like shape features of volumetric binary objects. Conventional thinning algorithms preserve endpoints to provide important geometric information relative to the object to be represented. An alternative strategy is also proposed that accumulates isthmuses (i.e., generalization of curve and surface interior points as skeletal elements). This paper presents two parallel isthmus-based 3D thinning algorithms that are capable of producing centerlines and medial surfaces. The strategy which is used is called subiteration-based or directional: each iteration step is composed of 12 subiterations each of which are executed in parallel. The proposed algorithms make efficient implementation possible and their topological correctness is guaranteed.

 

%B Advances in Visual Computing %S Lecture Notes in Computer Science %I Springer Verlag %C Heidelberg; New York %P 87 - 98 %8 Jul 2013 %G eng %9 Conference paper %R 10.1007/978-3-642-41914-0_10 %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %D 2013 %T Parallel Thinning Based on Isthmuses %A Gábor Németh %A Kálmán Palágyi %E László Czúni %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %I NJSZT-KÉPAF %C Veszprém %P 512 - 525 %8 Jan 2013 %G eng %9 Conference paper %0 Book Section %B International Conference on Cognitive Infocommunications (CogInfoCom) %D 2013 %T Parallel Thinning on the Triangular Grid %A Péter Kardos %A Kálmán Palágyi %E Péter Baranyi %X

One of the fundamental issues of human and computational cognitive psychology is pattern or shape recognition. Various applications in image processing and computer vision rely on skeleton-like shape features A possible technique for extracting these feautures is thinning. Although the majority of 2D thinning algorithms work on digital pictures sampled onthe conventional square grid, the role of some non-conventional grids, like the hexagonal and triangular grid, are of increasing importance as well. In this paper we propose numerous topolgy preserving parallel thinning algorithms that work on the triangular grid.

%B International Conference on Cognitive Infocommunications (CogInfoCom) %I IEEE %C Budapest %P 277 - 282 %8 Dec 2013 %@ 978-1-4799-1543-9 %G eng %9 Conference paper %M 14046653 %R 10.1109/CogInfoCom.2013.6719256 %0 Book Section %B International Conference on Digital Image Computing: Techniques and Applications (DICTA) %D 2013 %T Pose Estimation of Ad-hoc Mobile Camera Networks %A Zsolt Santa %A Zoltan Kato %E Paulo de Souza %E Ulrich Engelke %E Ashfaqur Rahman %X

An algorithm is proposed for the pose estimation of ad-hoc mobile camera networks with overlapping views. The main challenge is to estimate camera parameters with respect to the 3D scene without any specific calibration pattern, hence allowing for a consistent, camera-independent world coordinate system. The only assumption about the scene is that it contains a planar surface patch of a low-rank texture, which is visible in at least two cameras. Such low-rank patterns are quite common in urban environments. The proposed algorithm consists of three main steps: relative pose estimation of the cameras within the network, followed by the localization of the network within the 3D scene using a low-rank surface patch, and finally the estimation of a consistent scale for the whole system. The algorithm follows a distributed architecture, hence the computing power of the participating mobile devices are efficiently used. The performance and robustness of the proposed algorithm have been analyzed on both synthetic and real data. Experimental results confirmed the relevance and applicability of the method.

 

%B International Conference on Digital Image Computing: Techniques and Applications (DICTA) %I IEEE %C Hobart, TAS %P 88 - 95 %8 2013 %G eng %9 Conference paper %M 14000303 %R 10.1109/DICTA.2013.6691514 %0 Thesis %B Institute of Informatics %D 2013 %T Prior Information, Machine Learning, and Direction Dependency in Binary Tomography %A Péter Balázs %B Institute of Informatics %I University of Szeged %C Szeged, Hungary %8 2013 %G eng %9 Thesis %0 Book Section %B Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications (CIARP) %D 2013 %T Reconstruction and Enumeration of hv-Convex Polyominoes with Given Horizontal Projection %A Norbert Hantos %A Péter Balázs %E Jose Ruiz-Shulcloper %E Gabriella Sanniti di Baja %B Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications (CIARP) %S Lecture Notes in Computer Science %I Springer %C Heidelberg; London; New York %P 100 - 107 %8 Nov 2013 %@ 978-3-642-41821-1 %G eng %9 Conference paper %R 10.1007/978-3-642-41822-8_13 %0 Journal Article %J FUNDAMENTA INFORMATICAE %D 2013 %T The reconstruction of polyominoes from horizontal and vertical projections and morphological skeleton is NP-complete %A Norbert Hantos %A Péter Balázs %B FUNDAMENTA INFORMATICAE %V 125 %P 343 - 359 %8 2013 %@ 0169-2968 %G eng %N 3-4 %9 Journal article %! FUND INFOR %0 Book Section %B Advanced Concepts for Intelligent Vision Systems (ACIVS) %D 2013 %T Restoration of blurred binary images using discrete tomography %A Jozsef Nemeth %A Péter Balázs %E Jacques Blanc-Talon %E Andrzej Kasinski %E Wilfried Philips %E Dan Popescu %E Paul Scheunders %X

Enhancement of degraded images of binary shapes is an important task in many image processing applications, e.g. to provide appropriate image quality for optical character recognition. Although many image restoration methods can be found in the literature, most of them are developed for grayscale images. In this paper we propose a novel binary image restoration algorithm. As a first step, it restores the projections of the shape using 1-dimensional deconvolution, then reconstructs the image from these projections using a discrete tomography technique. The method does not require any parameter setting or prior knowledge like an estimation of the signal-to-noise ratio. Numerical experiments on a synthetic dataset show that the proposed algorithm is robust to the level of the noise. The efficiency of the method has also been demonstrated on real out-of-focus alphanumeric images.

 

%B Advanced Concepts for Intelligent Vision Systems (ACIVS) %S Lecture Notes in Computer Science %I Springer Verlag %C Berlin; Heidelberg; New York; London; Paris; Tokyo %P 80 - 90 %8 2013 %@ 978-3-319-02894-1 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-319-02895-8_8 %0 Journal Article %J ACTA CYBERNETICA-SZEGED %D 2013 %T Spectrum Skeletonization: A New Method for Acoustic Signal Feature Extraction. %A Tibor Dobján %A Gábor Németh %X

Vibration Analysis Tests (VAT) and Acoustic Emission tests (AE) are used in several industrial applications. Many of them perform analysis in the frequency domain. Peaks in the power density spectrum hold relevant information about acoustic events. In this paper we propose a novel method for feature extraction of vibration samples by analyzing the shape of their auto power spectrum density function. The approach uses skeletonization techniques in order to find the hierarchical structure of the spectral peaks. The proposed method can be applied as a preprocessing step for spectrum analysis of vibration signals.

%B ACTA CYBERNETICA-SZEGED %I University of Szeged, Institute of Informatics %C Szeged %V 21 %P 89 - 103 %8 2013 %@ 0324-721X %G eng %9 Journal article %! ACTA CYBERN-SZEGED %0 Book Section %B Proceedings of the IASTED International Conference on Computer Graphics and Imaging (CGIM) %D 2013 %T Sufficient Conditions for Topology Preserving Additions and General Operators %A Péter Kardos %A Kálmán Palágyi %E L Linsen %X

Topology preservation is a crucial issue of digital topology. Various applications of binary image processing rest on topology preserving operators. Earlier studies in this topic mainly concerned with reductions (i.e., operators that only delete some object points from binary images), as they form the basis for thinning algorithms. However, additions (i.e., operators that never change object points) also play important role for the purpose of generating discrete Voronoi diagrams or skeletons by influence zones (SKIZ). Furthermore, the use of general operators that may both add and delete some points to and from objects in pictures are suitable for contour smoothing. Therefore, in this paper we present some new sufficient conditions for topology preserving reductions, additions, and general operators. Two additions for 2D and 3D contour smoothing are also reported.

 

%B Proceedings of the IASTED International Conference on Computer Graphics and Imaging (CGIM) %I IASTED - Acta Press %C Calgary %P 107 - 114 %8 Feb 2013 %G eng %9 Conference paper %R 10.2316/P.2013.797-040 %0 Book Section %B Proceedings of ICCV Workshop on Big Data in 3D Computer Vision %D 2013 %T Targetless Calibration of a Lidar - Perspective Camera Pair %A Tamás Levente %A Zoltan Kato %E Jian Zhang %E Mohammed Bennamoun %E Dan Schonfeld %E Zhengyou Zhang %X

A novel method is proposed for the calibration of a camera - 3D lidar pair without the use of any special calibration pattern or point correspondences. The proposed method has no specific assumption about the data source: plain depth information is expected from the lidar scan and a simple perspective camera is used for the 2D images. The calibration is solved as a 2D-3D registration problem using a minimum of one (for extrinsic) or two (for intrinsic-extrinsic) planar regions visible in both cameras. The registration is then traced back to the solution of a non-linear system of equations which directly provides the calibration parameters between the bases of the two sensors. The method has been tested on a large set of synthetic lidar-camera image pairs as well as on real data acquired in outdoor environment.

 

%B Proceedings of ICCV Workshop on Big Data in 3D Computer Vision %I IEEE %C Sydney, NSW %P 668 - 675 %8 Dec 2013 %G eng %9 Conference paper %M 14147882 %R 10.1109/ICCVW.2013.92 %0 Book Section %B Proceedings of International Symposium on Image and Signal Processing and Analysis (ISPA) %D 2013 %T On Topology Preservation in Triangular, Square, and Hexagonal Grids %A Péter Kardos %A Kálmán Palágyi %E Giovanni Ramponi %E Sven Lončarić %E Alberto Carini %E Karen Egiazarian %X

There are three possible partitionings of the continuous plane into regular polygons that leads to triangular, square, and hexagonal grids. The topology of the square grid is fairly well-understood, but it cannot be said of the remaining two regular sampling schemes. This paper presents a general characterization of simple pixels and some simplified sufficient conditions for topology-preserving operators in all the three types of regular grids.

%B Proceedings of International Symposium on Image and Signal Processing and Analysis (ISPA) %I IEEE %C Trieste %P 782 - 787 %8 Sep 2013 %G eng %9 Conference paper %M 14027933 %R 10.1109/ISPA.2013.6703844 %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %D 2013 %T Topology preserving parallel thinning on hexagonal grids %A Péter Kardos %A Kálmán Palágyi %E László Czúni %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %I NJSZT-KÉPAF %C Veszprém %P 250 - 264 %8 Jan 2013 %G eng %9 Conference paper %0 Journal Article %J INTERNATIONAL JOURNAL OF COMPUTER MATHEMATICS %D 2013 %T Topology-preserving hexagonal thinning %A Péter Kardos %A Kálmán Palágyi %X

Thinning is a well-known technique for producing skeleton-like shape features from digital binary objects in a topology-preserving way. Most of the existing thinning algorithms work on input images that are sampled on orthogonal grids; however, it is also possible to perform thinning on hexagonal grids (or triangular lattices). In this paper, we point out to the main similarities and differences between the topological properties of these two types of sampling schemes. We give various characterizations of simple points and present some new sufficient conditions for topology-preserving reductions working on hexagonal grids.

%B INTERNATIONAL JOURNAL OF COMPUTER MATHEMATICS %I Taylor & Francis %V 90 %P 1607 - 1617 %8 2013 %@ 0020-7160 %G eng %U http://www.tandfonline.com/doi/abs/10.1080/00207160.2012.724198#preview %N 8 %9 Journal article %! INT J COMPUT MATH %R 10.1080/00207160.2012.724198 %0 Book Section %B Intelligent Interactive Technologies and Multimedia %D 2013 %T A unifying framework for correspondence-less shape alignment and its medical applications %A Zoltan Kato %X

We give an overview of our general framework for registering 2D and 3D objects without correspondences. Classical solutions consist in extracting landmarks, establishing correspondences and then the aligning transformation is obtained via a complex optimization procedure. In contrast, our framework works without landmark correspondences, is independent of the magnitude of transformation, easy to implement, and has a linear time complexity. The efficiency and robustness of the method has been demonstarted using various deformations models. Herein, we will focus on medical applications. © 2013 Springer-Verlag.

%B Intelligent Interactive Technologies and Multimedia %S Communications in Computer and Information Science %I Springer %C Allahabad, India %V 276 CCIS %P 40 - 52 %8 March 2013 %@ 1865-0929 %G eng %9 Conference paper %! COMMUN COMPUT INFORM SCI %R 10.1007/978-3-642-37463-0_4 %0 Conference Paper %B Proceedings of International Symposium on Image and Signal Processing and Analysis (ISPA) %D 2013 %T A uniqueness result for reconstructing hv-convex polyominoes from horizontal and vertical projections and morphological skeleton %A Norbert Hantos %A Péter Balázs %E Giovanni Ramponi %E Sven Lončarić %E Alberto Carini %E Karen Egiazarian %X

In this article we study the uniqueness of the reconstruction in a special class of 4-connected hv-convex images, using two projections and the so-called morphological skeleton. Generally, if just the two projections are given, there can be exponentially many hv-convex 4-connected images satisfying them. Knowing the morphological skeleton in addition, we can reduce the number of solutions. In the studied class, the images are defined by two parameters. We show that the uniqueness of their reconstruction depends only on the values of those parameters.

 

%B Proceedings of International Symposium on Image and Signal Processing and Analysis (ISPA) %I IEEE %C Trieste %P 788 - 793 %8 Sep 2013 %G eng %9 Conference paper %M 14027951 %R 10.1109/ISPA.2013.6703845 %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %D 2013 %T Vizuális kódok lokalizálásának javítása egyszerű jellemzők kombinációjával %A Péter Bodnár %A László Gábor Nyúl %E László Czúni %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %I NJSZT-KÉPAF %C Veszprém %P 483 - 495 %8 Jan 2013 %G hun %9 Conference paper %0 Book Section %B Advanced Concepts for Intelligent Vision Systems (ACIVS) %D 2012 %T 3D Parallel Thinning Algorithms Based on Isthmuses %A Gábor Németh %A Kálmán Palágyi %E Jacques Blanc-Talon %E Wilfried Philips %E Dan Popescu %E Paul Scheunders %E Pavel Zemčík %X

Thinning is a widely used technique to obtain skeleton-like shape features (i.e., centerlines and medial surfaces) from digital binary objects. Conventional thinning algorithms preserve endpoints to provide important geometric information relative to the object to be represented. An alternative strategy is also proposed that preserves isthmuses (i.e., generalization of curve/surface interior points). In this paper we present ten 3D parallel isthmus-based thinning algorithm variants that are derived from some sufficient conditions for topology preserving reductions.

%B Advanced Concepts for Intelligent Vision Systems (ACIVS) %S Lecture Notes in Computer Science %I Springer Verlag %C Brno, Czech Republic %V 7517 %P 325 - 335 %8 Sep 2012 %G eng %U http://dx.doi.org/10.1007/978-3-642-33140-4_29 %9 Conference Paper %! Conference Paper %R 10.1007/978-3-642-33140-4_29 %0 Generic %D 2012 %T Artificial intelligence methods in discrete tomography %A Mihály Gara %A Péter Balázs %X

Tomography is an imaging procedure to examine the internal structure of objects. The crosssection
images are constructed with the aid of the object’s projections. It is often necessary to
minimize the number of those projections to avoid the damage or destruction of the examined
object, since in most cases the projections are made by destructive rays.
Sometimes the number of available projections are so small that conventional methods cannot
provide satisfactory results. In these cases Discrete Tomograpy can provide acceptable solutions,
but it can only be used with the assumption the object is made of only a few materials,
thus only a small number of intensity values appear in the reconstructed cross-section image.
Although there are a lot of discrete tomographic reconstruction algorithms, only a few papers
deal with the determination of intensity values of the image, in advance. In our work we
try to fill this gap by using different learning methods. During the learning and classification
we used the projection values as input arguments.
In the second part of our talk we concentrate on Binary Tomography (a special kind of Discrete
Tomography)where it is supposed that the object is composed of onematerial. Thus, there
can be only two intensities on the cross-section image - one for the object points and one for
the background. Here, we compared our earlier presented binary tomographic evolutionary
reconstruction algorithm to two others. We present the details of the above-mentioned reconstruction
method and our experimental results. This paper is based on our previous works.

%B Conference of PhD students in computer science. Volume of Extended Abstracts. %I University Szeged, Institute of Informatics %C Szeged %P 16 %8 June 2012 %G eng %9 Abstract %0 Generic %D 2012 %T Barcode Detection with Uniform Partitioning and Morphological Operations %A Péter Bodnár %A László Gábor Nyúl %B Conference of PhD students in computer science. Volume of Extended Abstracts. %I University of Szeged, Institute of Informatics %C Szeged %P 4 - 5 %8 June 2012 %G eng %9 Abstract %0 Book Section %B Combinatorial Image Analysis %D 2012 %T Binary image reconstruction from two projections and skeletal information %A Norbert Hantos %A Péter Balázs %A Kálmán Palágyi %E Reneta P Barneva %E Valentin E Brimkov %E Jake K Aggarwal %X

In binary tomography, the goal is to reconstruct binary images from a small set of their projections. However, especially when only two projections are used, the task can be extremely underdetermined. In this paper, we show how to reduce ambiguity by using the morphological skeleton of the image as a priori. Three different variants of our method based on Simulated Annealing are tested using artificial binary images, and compared by reconstruction time and error. © 2012 Springer-Verlag.

%B Combinatorial Image Analysis %S Lecture Notes in Computer Science %I Springer Verlag %C Berlin; Heidelberg; New York; London; Paris; Tokyo %P 263 - 273 %8 Nov 2012 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-34732-0_20 %0 Book Section %B Image Analysis and Recognition %D 2012 %T A central reconstruction based strategy for selecting projection angles in binary tomography %A Péter Balázs %A Joost K Batenburg %E Aurélio Campilho %E Mohamed Kamel %X

In this paper we propose a novel strategy for selecting projection angles in binary tomography which yields significantly more accurate reconstructions than others. In contrast with previous works which are of experimental nature, the method we present is based on theoretical observations. We report on experiments for different phantom images to show the effectiveness and roboustness of our procedure. The practically important case of noisy projections is also studied. © 2012 Springer-Verlag.

%B Image Analysis and Recognition %S Lecture Notes in Computer Science %I Springer %C Berlin; Heidelberg; New York; London; Paris; Tokyo %P 382 - 391 %8 June 2012 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-31295-3_45 %0 Generic %D 2012 %T Empirical studies of reconstructing hv-convex binary matrices from horizontal and vertical projections %A Zoltán Ozsvár %A Péter Balázs %B Conference of PhD students in computer science. Volume of Extended Abstracts. %I University of Szeged, Institute of Informatics %C Szeged %P 44 %8 June 2012 %G eng %9 Abstract %0 Book Section %B Computational Modelling of Objects Represented in Images: Fundamentals, Methods and Applications III %D 2012 %T An energy minimization reconstruction algorithm for multivalued discrete tomography %A László Gábor Varga %A Péter Balázs %A Antal Nagy %E Paolo Di Giamberardino %E Daniela Iacoviello %E Renato M Natal Jorge %E Joao Manuel R S Taveres %X

We propose a new algorithm for multivalued discrete tomography, that reconstructs images from few projections by approximating the minimum of a suitably constructed energy function with a deterministic optimization method. We also compare the proposed algorithm to other reconstruction techniques on software phantom images, in order to prove its applicability.

%B Computational Modelling of Objects Represented in Images: Fundamentals, Methods and Applications III %I CRC Press - Taylor and Frances Group %C London %P 179 - 185 %8 2012 %G eng %9 Conference paper %R 10.1201/b12753-1 %0 Generic %D 2012 %T Extracting geometrical features of discrete images from their projections %A Tamás Sámuel Tasi %A Péter Balázs %B Conference of PhD students in computer science. Volume of Extended Abstracts. %I University of Szeged, Institute of Informatics %C Szeged %P 52 %8 June 2012 %G eng %9 Abstract %0 Book Section %B Computational Modelling of Objects Represented in Images: Fundamentals, Methods and Applications III %D 2012 %T Hexagonal parallel thinning algorithms based on sufficient conditions for topology preservation %A Péter Kardos %A Kálmán Palágyi %E Paolo Di Giamberardino %E Daniela Iacoviello %E Renato M Natal Jorge %E Joao Manuel R S Taveres %X

Thinning is a well-known technique for producing skeleton-like shape features from digital
binary objects in a topology preserving way. Most of the existing thinning algorithms presuppose that the input
images are sampled on orthogonal grids.This paper presents new sufficient conditions for topology preserving
reductions working on hexagonal grids (or triangular lattices) and eight new 2D hexagonal parallel thinning
algorithms that are based on our conditions.The proposed algorithms are capable of producing both medial lines
and topological kernels as well.

%B Computational Modelling of Objects Represented in Images: Fundamentals, Methods and Applications III %I CRC Press - Taylor and Frances Group %C London %P 63 - 68 %8 2012 %@ 978-0-415-62134-2 %G eng %9 Conference paper %R 10.1201/b12753-12 %0 Conference Paper %B Proceedings of the International Conference on Signal Image Technology & Internet Systems (SITIS) %D 2012 %T Improving barcode detection with combination of simple detectors %A Péter Bodnár %A László Gábor Nyúl %E Kokou Yetongnon %E Richard Chbeir %E Albert Dipanda %E Luigi Gallo %X

Barcode detection is required in a wide range of real-life applications. Imaging conditions and techniques vary considerably and each application has its own requirements for detection speed and accuracy. In our earlier works we built barcode detectors using morphological operations and uniform partitioning with several approaches and showed their behaviour on a set of test images. In this work, we examine ensemble efficiency of those simple detectors using various aggregation methods. Using a combination of several simple features localization performance improves significantly.

 

%B Proceedings of the International Conference on Signal Image Technology & Internet Systems (SITIS) %I IEEE %C Naples, Italy %P 300 - 306 %8 Nov 2012 %G eng %9 Conference paper %M 13227628 %R 10.1109/SITIS.2012.52 %0 Conference Paper %B IASTED International Conference on Signal Processing, Pattern Recognition and Applications (SSPRA) %D 2012 %T Isthmus-based Order-Independent Sequential Thinning %A Péter Kardos %A Kálmán Palágyi %E M Petrou %E A D Sappa %E A G Triantafyllidis %X

Thinning as a layer-by-layer reduction is a frequently used technique for skeletonization. Sequential thinning algorithms usually suffer from the drawback of being order-dependent, i.e., their results depend on the visiting order of object points. Earlier order-independent sequential methods are based on the conventional thinning schemes that preserve endpoints to provide relevant geometric information of objects. These algorithms can generate centerlines in 2D and medial surfaces in 3D. This paper presents an alternative strategy for order-independent thinning which follows an approach, proposed by Bertrand and Couprie, which accumulates so-called isthmus points. The main advantage of this order-independent strategy over the earlier ones is that it makes also possible to produce centerlines of 3D objects.

%B IASTED International Conference on Signal Processing, Pattern Recognition and Applications (SSPRA) %I IASTED ACTA Press %C Crete, Greek %P 28 - 34 %8 June 2012 %G eng %U http://www.actapress.com/Content_of_Proceeding.aspx?proceedingID=736 %9 Conference paper %R 10.2316/P.2012.778-025 %0 Book Section %B Applications of Discrete Geometry and Mathematical Morphology (WADGMM) %D 2012 %T Machine learning as a preprocessing phase in discrete tomography %A Mihály Gara %A Tamás Sámuel Tasi %A Péter Balázs %E Ullrich Köthe %E Annick Montanvert %E Pierre Soille %X

In this paper we investigate for two well-known machine learning methods, decision trees and neural networks, how they classify discrete images from their projections. As an example, we present classification results when the task is to guess the number of intensity values of the discrete image. Machine learning can be used in Discrete Tomography as a preprocessing step in order to choose the proper reconstruction algorithm or - with the aid of the knowledge acquired - to improve its accuracy. We also show how to design new evolutionary reconstruction methods that can exploit the information gained by machine learning classifiers. © 2012 Springer-Verlag.

%B Applications of Discrete Geometry and Mathematical Morphology (WADGMM) %S Lecture Notes in Computer Science %I Springer Verlag %C Berlin; Heidelberg; New York; London; Paris; Tokyo %P 109 - 124 %8 Aug 2012 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-32313-3_8 %0 Book %D 2012 %T Markov random fields in image segmentation %A Zoltan Kato %A Josiane Zerubia %X

Markov Random Fields in Image Segmentation introduces the fundamentals of Markovian modeling in image segmentation as well as providing a brief overview of recent advances in the field.

%I Now Publishers %C Hanover, NH %8 2012 %G eng %9 Book %0 Conference Paper %B International Conference on Pattern Recognition (ICPR) %D 2012 %T A Multi-Layer Phase Field Model for Extracting Multiple Near-Circular Objects %A Csaba Molnar %A Zoltan Kato %A Ian Jermyn %E Jan-Olof Eklundh %E Yuichi Ohta %E Steven Tanimoto %X

This paper proposes a functional that assigns low `energy' to sets of subsets of the image domain consisting of a number of possibly overlapping near-circular regions of approximately a given radius: a `gas of circles'. The model can be used as a prior for object extraction whenever the objects conform to the `gas of circles' geometry, e.g. cells in biological images. Configurations are represented by a multi-layer phase field. Each layer has an associated function, regions being defined by thresholding. Intra-layer interactions assign low energy to configurations consisting of non-overlapping near-circular regions, while overlapping regions are represented in separate layers. Inter-layer interactions penalize overlaps. Here we present a theoretical and experimental analysis of the model.

 

%B International Conference on Pattern Recognition (ICPR) %I IEEE %C Tsukuba, Japan %P 1427 - 1430 %8 Nov 2012 %@ 978-1-4673-2216-4 %G eng %9 Conference paper %M 13324819 %0 Journal Article %J IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE %D 2012 %T Nonlinear Shape Registration without Correspondences %A Csaba Domokos %A Jozsef Nemeth %A Zoltan Kato %X

In this paper, we propose a novel framework to estimate the parameters of a diffeomorphism that aligns a known shape and its distorted observation. Classical registration methods first establish correspondences between the shapes and then compute the transformation parameters from these landmarks. Herein, we trace back the problem to the solution of a system of nonlinear equations which directly gives the parameters of the aligning transformation. The proposed method provides a generic framework to recover any diffeomorphic deformation without established correspondences. It is easy to implement, not sensitive to the strength of the deformation, and robust against segmentation errors. The method has been applied to several commonly used transformation models. The performance of the proposed framework has been demonstrated on large synthetic data sets as well as in the context of various applications.

 

%B IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE %I IEEE %V 34 %P 943 - 958 %8 2012 %@ 0162-8828 %G eng %U http://www.inf.u-szeged.hu/~kato/papers/TPAMI-2010-03-0146.R2_Kato.pdf %N 5 %9 Journal article %M 12617610 %! IEEE T PATTERN ANAL %R 10.1109/TPAMI.2011.200 %0 Conference Paper %B Proceedings of the International Conference on Signal Image Technology & Internet Systems (SITIS) %D 2012 %T A novel method for accurate and efficient barcode detection with morphological operations %A Melinda Katona %A László Gábor Nyúl %E Kokou Yetongnon %E Richard Chbeir %E Albert Dipanda %E Luigi Gallo %X

Barcode technology is the pillar of automatic identification, that is used in a wide range of real-time applications with various types of codes. The different types of codes and applications impose special problems, so there is a continuous need for solutions with improved effectiveness. There are several methods for barcode localization, that are well characterized by accuracy and speed. Particularly, high-speed processing places need automatic barcode localization, e.g. conveyor belts, automated production, where missed detections cause loss of profit. In this paper, we mainly deal with segmentation of images with 1D barcode, but also analyze the operation of different methods for 2D barcode images as well. Our goal is to detect automatically, rapidly and accurately the barcode location by the help of extracted features. We compare some published method from the literature, which basically rely on the contrast between the background and the shape that represent the code. We also propose a novel algorithm, that outperforms the others in both accuracy and efficiency in detecting 1D codes.

 

%B Proceedings of the International Conference on Signal Image Technology & Internet Systems (SITIS) %I IEEE %C Naples, Italy %P 307 - 314 %8 Nov 2012 %@ 978-1-4673-5152-2 %G eng %9 Conference paper %M 13227629 %R 10.1109/SITIS.2012.53 %0 Generic %D 2012 %T A novel optimization-based reconstruction algorithm for multivalued discrete tomography %A László Gábor Varga %A Péter Balázs %A Antal Nagy %B Conference of PhD students in computer science. Volume of extended abstracts. %I University of Szeged, Institute of Informatics %C Szeged %P 57 %8 June 2012 %G eng %9 Abstract %0 Conference Paper %B Veszprém Optimization Conference: Advanced Algorithms (Vocal) %D 2012 %T An optimization-based reconstruction algorithm for multivalued discrete tomography %A László Gábor Varga %A Péter Balázs %A Antal Nagy %B Veszprém Optimization Conference: Advanced Algorithms (Vocal) %I University of Pannonia %C Veszprém %P 39 - 40 %8 Dec 2012 %G eng %9 Conference paper %0 Conference Paper %B IEEE International Conference on Cognitive Infocommunications (CogInfoCom) %D 2012 %T On Order–Independent Sequential Thinning %A Péter Kardos %A Kálmán Palágyi %E IEEE %X

The visual world composed by the human and computational cognitive systems strongly relies on shapes of objects. Skeleton is a widely applied shape feature that plays an important role in many fields of image processing, pattern recognition, and computer vision. Thinning is a frequently used, iterative object reduction strategy for skeletonization. Sequential thinning algorithms, which are based on contour tracking, delete just one border point at a time. Most of them have the disadvantage of order-dependence, i.e., for dissimilar visiting orders of object points, they may generate different skeletons. In this work, we give a survey of our results on order-independent thinning: we introduce some sequential algorithms that produce identical skeletons for any visiting orders, and we also present some sufficient conditions for the order-independence of templatebased sequential algorithms.

%B IEEE International Conference on Cognitive Infocommunications (CogInfoCom) %I IEEE %C Kosice, Slovakia %P 149 - 154 %8 2012 %@ 978-1-4673-5187-4 %G eng %U http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=6413305 %9 Conference paper %R 10.1109/CogInfoCom.2012.6421971 %0 Book Section %B Advanced color image processing and analysis %D 2012 %T Parametric Stochastic Modeling for Color Image Segmentation and Texture Characterization %A Imtnan-Ul-Haque Qazi %A Oliver Alata %A Zoltan Kato %E Christine Fernandez-Maloigne %X

Black should be made a color of light Clemence Boulouque

Parametric stochastic models offer the definition of color and/or texture features based on model parameters, which is of interest for color texture classification, segmentation and synthesis.

In this chapter, distribution of colors in the images through various parametric approximations including multivariate Gaussian distribution, multivariate Gaussian mixture models (MGMM) and Wishart distribution, is discussed. In the context of Bayesian color image segmentation, various aspects of sampling from the posterior distributions to estimate the color distribution from MGMM and the label field, using different move types are also discussed. These include reversible jump mechanism from MCMC methodology. Experimental results on color images are presented and discussed.

Then, we give some materials for the description of color spatial structure using Markov Random Fields (MRF), and more particularly multichannel GMRF, and multichannel linear prediction models. In this last approach, two dimensional complex multichannel versions of both causal and non-causal models are discussed to perform the simultaneous parametric power spectrum estimation of the luminance and the chrominance channels of the color image. Application of these models to the classification and segmentation of color texture images is also illustrated.

 

%B Advanced color image processing and analysis %I Springer %C Berlin; Heidelberg; New York; London; Paris; Tokyo %P 279 - 325 %8 2012 %@ 978-1-4419-6189-1 %G eng %9 Book chapter %R 10.1007/978-1-4419-6190-7_9 %0 Conference Paper %B IASTED International Conference on Signal Processing, Pattern Recognition and Applications (SPPRA) %D 2012 %T Perimeter estimation of some discrete sets from horizontal and vertical projections %A Tamás Sámuel Tasi %A M Hegedűs %A Péter Balázs %E M Petrou %E A D Sappa %E A G Triantafyllidis %X

In this paper, we design neural networks to estimate the perimeter of simple and more complex discrete sets from their horizontal and vertical projections. The information extracted this way can be useful to simplify the problem of reconstructing the discrete set from its projections, which task is in focus of discrete tomography. Beside presenting experimental results with neural networks, we also reveal some statistical properties of the perimeter of the studied discrete sets.

%B IASTED International Conference on Signal Processing, Pattern Recognition and Applications (SPPRA) %I IASTED ACTA Press %C Crete, Greek %P 174 - 181 %8 June 2012 %G eng %9 Conference paper %R 10.2316/P.2012.778-017 %0 Conference Paper %B International Conference on Pattern Recognition (ICPR) %D 2012 %T Simultaneous Affine Registration of Multiple Shapes %A Csaba Domokos %A Zoltan Kato %E Jan-Olof Eklundh %E Yuichi Ohta %E Steven Tanimoto %X

The problem of simultaneously estimating affine deformations between multiple objects occur in many applications. Herein, a direct method is proposed which provides the result as a solution of a linear system of equations without establishing correspondences between the objects. The key idea is to construct enough linearly independent equations using covariant functions, and then finding the solution simultaneously for all affine transformations. Quantitative evaluation confirms the performance of the method.

 

%B International Conference on Pattern Recognition (ICPR) %I IEEE %C Tsukuba, Japan %P 9 - 12 %8 Nov 2012 %@ 978-1-4673-2216-4 %G eng %9 Conference paper %M 13324478 %0 Conference Paper %B Veszprém Optimization Conference: Advanced Algorithms (VOCAL) %D 2012 %T Solving binary tomography from morphological skeleton via optimization %A Norbert Hantos %A Péter Balázs %A Kálmán Palágyi %B Veszprém Optimization Conference: Advanced Algorithms (VOCAL) %I University of Pannonia %C Veszprém %P 42 %8 Dec 2012 %G eng %9 Conference paper %0 Conference Paper %B International Conference on Pattern Recognition (ICPR) %D 2012 %T Spectral clustering to model deformations for fast multimodal prostate registration %A Jhimli Mitra %A Zoltan Kato %A Soumya Ghose %A Desire Sidibe %A Robert Martí %A Xavier Lladó %A Oliver Arnau %A Joan C Vilanova %A Fabrice Meriaudeau %E Jan-Olof Eklundh %E Yuichi Ohta %E Steven Tanimoto %X

This paper proposes a method to learn deformation parameters off-line for fast multimodal registration of ultrasound and magnetic resonance prostate images during ultrasound guided needle biopsy. The registration method involves spectral clustering of the deformation parameters obtained from a spline-based nonlinear diffeomorphism between training magnetic resonance and ultrasound prostate images. The deformation models built from the principal eigen-modes of the clusters are then applied on a test magnetic resonance image to register with the test ultrasound prostate image. The deformation model with the least registration error is finally chosen as the optimal model for deformable registration. The rationale behind modeling deformations is to achieve fast multimodal registration of prostate images while maintaining registration accuracies which is otherwise computationally expensive. The method is validated for 25 patients each with a pair of corresponding magnetic resonance and ultrasound images in a leave-one-out validation framework. The average registration accuracies i.e. Dice similarity coefficient of 0.927 ± 0.025, 95% Hausdorff distance of 5.14 ± 3.67 mm and target registration error of 2.44 ± 1.17 mm are obtained by our method with a speed-up in computation time by 98% when compared to Mitra et al. [7].

 

%B International Conference on Pattern Recognition (ICPR) %I IEEE %C Tsukuba, Japan %P 2622 - 2625 %8 Nov 2012 %@ 978-1-4673-2216-4 %G eng %U http://hal.archives-ouvertes.fr/docs/00/71/09/43/PDF/ICPR_Jhimli.pdf %9 Conference paper %M 13325059 %0 Journal Article %J MEDICAL IMAGE ANALYSIS %D 2012 %T A spline-based non-linear diffeomorphism for multimodal prostate registration. %A Jhimli Mitra %A Zoltan Kato %A Robert Martí %A Oliver Arnau %A Xavier Lladó %A Desire Sidibe %A Soumya Ghose %A Joan C Vilanova %A Josep Comet %A Fabrice Meriaudeau %X

This paper presents a novel method for non-rigid registration of transrectal ultrasound and magnetic resonance prostate images based on a non-linear regularized framework of point correspondences obtained from a statistical measure of shape-contexts. The segmented prostate shapes are represented by shape-contexts and the Bhattacharyya distance between the shape representations is used to find the point correspondences between the 2D fixed and moving images. The registration method involves parametric estimation of the non-linear diffeomorphism between the multimodal images and has its basis in solving a set of non-linear equations of thin-plate splines. The solution is obtained as the least-squares solution of an over-determined system of non-linear equations constructed by integrating a set of non-linear functions over the fixed and moving images. However, this may not result in clinically acceptable transformations of the anatomical targets. Therefore, the regularized bending energy of the thin-plate splines along with the localization error of established correspondences should be included in the system of equations. The registration accuracies of the proposed method are evaluated in 20 pairs of prostate mid-gland ultrasound and magnetic resonance images. The results obtained in terms of Dice similarity coefficient show an average of 0.980+/-0.004, average 95% Hausdorff distance of 1.63+/-0.48mm and mean target registration and target localization errors of 1.60+/-1.17mm and 0.15+/-0.12mm respectively.

%B MEDICAL IMAGE ANALYSIS %V 16 %P 1259 - 1279 %8 Aug 2012 %@ 1361-8415 %G eng %N 6 %9 Journal article %! MED IMAGE ANAL %R 10.1016/j.media.2012.04.006 %0 Book Section %B Combinatorial Image Analysis (IWCIA) %D 2012 %T On topology preservation for triangular thinning algorithms %A Péter Kardos %A Kálmán Palágyi %E Reneta P Barneva %E Valentin E Brimkov %E Jake K Aggarwal %X

Thinning is a frequently used strategy to produce skeleton-like shape features of binary objects. One of the main problems of parallel thinning is to ensure topology preservation. Solutions to this problem have been already given for the case of orthogonal and hexagonal grids. This work introduces some characterizations of simple pixels and some sufficient conditions for parallel thinning algorithms working on triangular grids (or hexagonal lattices) to preserve topology.

%B Combinatorial Image Analysis (IWCIA) %S Lecture Notes in Computer Science %I Springer Verlag %C Austin, TX, USA %P 128 - 142 %8 Nov 2012 %@ 978-3-642-34731-3 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-34732-0_10 %0 Book Section %B Digital Geometry Algorithms %D 2012 %T Topology Preserving Parallel 3D Thinning Algorithms %A Kálmán Palágyi %A Gábor Németh %A Péter Kardos %E Valentin E Brimkov %E Reneta P Barneva %X

A widely used technique to obtain skeletons of binary objects is thinning, which is an iterative layer-by-layer erosion in a topology preserving way. Thinning in 3D is capable of extracting various skeleton-like shape descriptors (i.e., centerlines, medial surfaces, and topological kernels). This chapter describes a family of new parallel 3D thinning algorithms for (26, 6) binary pictures. The reported algorithms are derived from some sufficient conditions for topology preserving parallel reduction operations, hence their topological correctness is guaranteed.

%B Digital Geometry Algorithms %S Lecture Notes in Computational Vision and Biomechanics %I Springer-Verlag %P 165 - 188 %8 2012 %@ 978-94-007-4173-7 %G eng %9 Book chapter %& 6 %R 10.1007/978-94-007-4174-4_6 %0 Book Section %B International Conference on Image Analysis and Recognition (ICIAR) %D 2012 %T A Unifying Framework for Correspondence-less Linear Shape Alignment %A Zoltan Kato %E Aurélio Campilho %X

We consider the estimation of linear transformations aligning a known binary shape and its distorted observation. The classical way to solve this registration problem is to find correspondences between the two images and then compute the transformation parameters from these landmarks. Here we propose a unified framework where the exact transformation is obtained as the solution of either a polynomial or a linear system of equations without establishing correspondences. The advantages of the proposed solutions are that they are fast, easy to implement, have linear time complexity, work without landmark correspondences and are independent of the magnitude of transformation.

 

%B International Conference on Image Analysis and Recognition (ICIAR) %S Lecture Notes in Computer Science %I Springer Verlag %C Aveiro, Portugal %P 277 - 284 %8 June 2012 %@ 978-3-642-31294-6 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-31295-3_33 %0 Conference Paper %B IEEE International Conference on Cognitive Infocommunications (CogInfoCom) %D 2012 %T A Unifying Framework for Non-linear Registration of 3D Objects %A Zsolt Santa %A Zoltan Kato %X

An extension of our earlier work is proposed to find a non-linear aligning transformation between a pair of deformable 3D objects. The basic idea is to set up a system of nonlinear equations whose solution directly provides the parameters of the aligning transformation. Each equation is generated by integrating a nonlinear function over the object's domains. Thus the number of equations is determined by the number of adopted nonlinear functions yielding a flexible mechanism to generate sufficiently many equations. While classical approaches would establish correspondences between the shapes, our method works without landmarks. Experiments with 3D polynomial and thin plate spline deformations confirm the performance of the framework.

 

%B IEEE International Conference on Cognitive Infocommunications (CogInfoCom) %I IEEE %C Kosice, Slovakia %P 547 - 552 %8 Dec 2012 %@ 978-1-4673-5187-4 %G eng %U http://www.inf.u-szeged.hu/~kato/papers/coginfocomm2012.pdf %9 Conference paper %R 10.1109/CogInfoCom.2012.6422041 %0 Conference Paper %B Proceedings of the International Symposium on Image and Signal Processing and Analysis (ISPA) %D 2011 %T 2D Parallel Thinning Algorithms Based on Isthmus-Preservation %A Gábor Németh %A Kálmán Palágyi %E Sven Lončarić %E Giovanni Ramponi %E D. Sersic %X

Skeletons are widely used shape descriptors which summarize the general form of binary objects. A technique to obtain skeletons is the thinning, that is an iterative layer-by-layer erosion in a topology-preserving way. Conventional thinning algorithms preserve line endpoints to provide important geometric information relative to the object to be represented. Bertrand and Couprie proposed an alternative strategy by accumulating isthmus points that are line interior points. In this paper we present six new 2D parallel thinning algorithms that are derived from some sufficient conditions for topology preserving reductions and based on isthmus-preservation.

%B Proceedings of the International Symposium on Image and Signal Processing and Analysis (ISPA) %I IEEE %C Dubrovnik, Croatia %P 585 - 590 %8 Sep 2011 %@ 978-1-4577-0841-1 %G eng %9 Conference paper %M 12307467 %0 Journal Article %J ACTA CYBERNETICA-SZEGED %D 2011 %T 2D parallel thinning and shrinking based on sufficient conditions for topology preservation %A Gábor Németh %A Péter Kardos %A Kálmán Palágyi %X

Thinning and shrinking algorithms, respectively, are capable of extracting medial lines and topological kernels from digital binary objects in a topology preserving way. These topological algorithms are composed of reduction operations: object points that satisfy some topological and geometrical constraints are removed until stability is reached. In this work we present some new sufficient conditions for topology preserving parallel reductions and fiftyfour new 2D parallel thinning and shrinking algorithms that are based on our conditions. The proposed thinning algorithms use five characterizations of endpoints.

%B ACTA CYBERNETICA-SZEGED %I University of Szeged, Institute of Informatics %C Szeged %V 20 %P 125 - 144 %8 2011 %@ 0324-721X %G eng %N 1 %9 Journal article %! ACTA CYBERN-SZEGED %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %D 2011 %T 3D objektumok lineáris deformációinak becslése %A Attila Tanacs %A Joakim Lindblad %A Nataša Sladoje %A Zoltan Kato %E Zoltan Kato %E Kálmán Palágyi %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %I NJSZT %C Szeged %P 471 - 480 %8 Jan 2011 %G eng %9 Conference paper %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %D 2011 %T Affin Puzzle: Deformált objektumdarabok helyreállítása megfeleltetések nélkül %A Csaba Domokos %A Zoltan Kato %E Zoltan Kato %E Kálmán Palágyi %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %I NJSZT %C Szeged %P 206 - 220 %8 Jan 2011 %G eng %U http://www.inf.u-szeged.hu/kepaf2011/pdfs/S05_03.pdf %9 Conference paper %0 Journal Article %J ACTA CYBERNETICA-SZEGED %D 2011 %T Conference of PhD Students in Computer Science %A Kálmán Palágyi %B ACTA CYBERNETICA-SZEGED %V 20 %P 3 %8 2011 %@ 0324-721X %G eng %N 1 %9 Journal article %! ACTA CYBERN-SZEGED %0 Journal Article %J GRAPHICAL MODELS %D 2011 %T Direction-dependency of binary tomographic reconstruction algorithms %A László Gábor Varga %A Péter Balázs %A Antal Nagy %X

In this work we study the relation between the quality of a binary tomographic reconstruction and the choice of angles of the projections. We conduct experiments on a set of software phantoms by reconstructing them from different projection sets using three different discrete tomography reconstruction algorithms, and compare the accuracy of the corresponding reconstructions with suitable approaches. To validate our results for possible real-world applications, we conduct the experiments by adding random noise of different characteristics to the simulated projection data, and by applying small topological changes on the phantom images as well. In addition, we also discuss some consequences of the angle-selection dependency and possible practical applications arising from the field of non-destructive testing, too.

%B GRAPHICAL MODELS %V 73 %P 365 - 375 %8 Nov 2011 %@ 1524-0703 %G eng %N 6 %9 Journal article %! GRAPH MODELS %R 10.1016/j.gmod.2011.06.006 %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %D 2011 %T Élősejt szegmentálása gráfvágás segítségével fluoreszcenciás mikroszkóp képeken %A Milan Lesko %A Zoltan Kato %A Antal Nagy %A Imre Gombos %A Zsolt Török %A László Vígh %A László Vígh %E Zoltan Kato %E Kálmán Palágyi %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %I NJSZT %C Szeged %P 319 - 328 %8 Jan 2011 %G eng %U http://www.inf.u-szeged.hu/kepaf2011/pdfs/S08_02.pdf %9 Conference paper %0 Book Section %B Combinatorial Image Analysis (IWCIA) %D 2011 %T A family of topology-preserving 3d parallel 6-subiteration thinning algorithms %A Gábor Németh %A Péter Kardos %A Kálmán Palágyi %E Jake K Aggarwal %E Reneta P Barneva %E Valentin E Brimkov %E Kostadin N Koroutchev %E Elka R Korutcheva %X

Thinning is an iterative layer-by-layer erosion until only the skeleton-like shape features of the objects are left. This paper presents a family of new 3D parallel thinning algorithms that are based on our new sufficient conditions for 3D parallel reduction operators to preserve topology. The strategy which is used is called subiteration-based: each iteration step is composed of six parallel reduction operators according to the six main directions in 3D. The major contributions of this paper are: 1) Some new sufficient conditions for topology preserving parallel reductions are introduced. 2) A new 6-subiteration thinning scheme is proposed. Its topological correctness is guaranteed, since its deletion rules are derived from our sufficient conditions for topology preservation. 3) The proposed thinning scheme with different characterizations of endpoints yields various new algorithms for extracting centerlines and medial surfaces from 3D binary pictures. © 2011 Springer-Verlag Berlin Heidelberg.

%B Combinatorial Image Analysis (IWCIA) %S Lecture Notes in Computer Science %I Springer Verlag %C Madrid, Spain %P 17 - 30 %8 May 2011 %@ 978-3-642-21072-3 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-21073-0_5 %0 Conference Paper %B Biomedical Engineering and Informatics (BMEI) %D 2011 %T Fast linear registration of 3D objects segmented from medical images %A Attila Tanacs %A Zoltan Kato %E Yongsheng Ding %E Yonghong Peng %E Riyi Shi %E Kuangrong Hao %E Lipo Wang %X

In this paper a linear registration framework is used for medical image registration using segmented binary objects. The method is best suited for problems where the segmentation is available, but we also propose a general bone segmentation approach for CT images. We focus on the case when the objects to be registered differ considerably because of segmentation errors. We check the applicability of the method to bone segmentation of pelvic and thoracic CT images. Comparison is also made against a classical mutual information-based registration method. © 2011 IEEE.

%B Biomedical Engineering and Informatics (BMEI) %I IEEE %C Shanghai %P 294 - 298 %8 Oct 2011 %@ 978-1-4244-9351-7 %G eng %9 Conference paper %M 12436502 %R 10.1109/BMEI.2011.6098290 %0 Book %D 2011 %T Fejlett Grafikai Algoritmusok %A Antal Nagy %I Typotex Kiadó %C Budapest %8 2011 %G eng %9 Book %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %D 2011 %T Iterációnkénti simítással kombinált vékonyítás %A Péter Kardos %A Gábor Németh %A Kálmán Palágyi %E Zoltan Kato %E Kálmán Palágyi %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %I NJSZT %C Szeged %P 174 - 189 %8 Jan 2011 %G eng %U http://www.inf.u-szeged.hu/kepaf2011/pdfs/S05_01.pdf %9 Conference paper %0 Book %D 2011 %T Képfeldolgozás haladóknak %A Kálmán Palágyi %I Typotex %C Budapest %8 2011 %G eng %9 Book %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %D 2011 %T Mediánszűrés alkalmazása algebrai rekonstrukciós módszerekben %A Norbert Hantos %A Péter Balázs %E Zoltan Kato %E Kálmán Palágyi %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %I NJSZT %C Szeged %P 106 - 116 %8 Jan 2011 %G eng %9 Conference paper %0 Conference Proceedings %B Multispectral Image Acquisition, Processing, and Analysis (MIPPR) %D 2011 %T MIPPR 2011: Multispectral Image Acquisition, Processing, and Analysis %E Zhigou Cao %E Aaron Fenster %E László Gábor Nyúl %E Chao Cai %B Multispectral Image Acquisition, Processing, and Analysis (MIPPR) %I SPIE %C Guilin, China %V 8002 %8 2011 %G eng %9 Conference proceedings %0 Conference Paper %B International Conference on Digital Image Computing: Techniques and Applications (DICTA) %D 2011 %T A non-linear diffeomorphic framework for prostate multimodal registration %A Jhimli Mitra %A Zoltan Kato %A Robert Martí %A Oliver Arnau %A Xavier Lladó %A Soumya Ghose %A Joan C Vilanova %A Fabrice Meriaudeau %X

This paper presents a novel method for non-rigid registration of prostate multimodal images based on a nonlinear framework. The parametric estimation of the non-linear diffeomorphism between the 2D fixed and moving images has its basis in solving a set of non-linear equations of thin-plate splines. The regularized bending energy of the thin-plate splines along with the localization error of established correspondences is jointly minimized with the fixed and transformed image difference, where, the transformed image is represented by the set of non-linear equations defined over the moving image. The traditional thin-plate splines with established correspondences may provide good registration of the anatomical targets inside the prostate but may fail to provide improved contour registration. On the contrary, the proposed framework maintains the accuracy of registration in terms of overlap due to the non-linear thinplate spline functions while also producing smooth deformations of the anatomical structures inside the prostate as a result of established corrspondences. The registration accuracies of the proposed method are evaluated in 20 pairs of prostate midgland ultrasound and magnetic resonance images in terms of Dice similarity coefficient with an average of 0.982 ± 0.004, average 95% Hausdorff distance of 1.54 ± 0.46 mm and mean target registration and target localization errors of 1.90±1.27 mm and 0.15 ± 0.12 mm respectively. © 2011 IEEE.

%B International Conference on Digital Image Computing: Techniques and Applications (DICTA) %I IEEE %C Noosa, QLD %P 31 - 36 %8 Dec 2011 %@ 978-1-4577-2006-2 %G eng %9 Conference paper %M 12476651 %R 10.1109/DICTA.2011.14 %0 Generic %D 2011 %T Nonlinear Shape Registration without Correspondences %A Zoltán Kornél Török %A Csaba Domokos %A Jozsef Nemeth %A Zoltan Kato %X

This is the sample implementation and benchmark dataset of the nonlinear registration of 2D shapes described in the following papers: Csaba Domokos, Jozsef Nemeth, and Zoltan Kato. Nonlinear Shape Registration without Correspondences. IEEE Transactions on Pattern Analysis and Machine Intelligence, 34(5):943--958, May 2012. Note that the current demo program implements only planar homography deformations. Other deformations can be easily implemented based on the demo code.

%8 2011/// %G eng %U http://www.inf.u-szeged.hu/~kato/software/planarhombinregdemo.html %9 Software %0 Conference Paper %B Signal and Image Processing and Applications (SIPA) %D 2011 %T Order-independent sequential thinning in arbitrary dimensions %A Péter Kardos %A Kálmán Palágyi %E Ioannis Andreadis %E M Zervakis %X

Skeletons are region based shape descriptors that play important role in shape representation. This paper introduces a novel sequential thinning approach for n-dimensional binary objects (n =1,2,3, ...). Its main strength lies in its order--independency, i.e., it can produce the same skeletons for any visiting orders of border points. Furthermore, this is the first scheme in this field that is also applicable for higher dimensions.

%B Signal and Image Processing and Applications (SIPA) %I IASTED - Acta Press %C Crete, Greek %P 129 - 134 %8 June 2011 %G eng %9 Conference paper %R 10.2316/P.2011.738-021 %0 Book Section %B Képi információ mérése %D 2011 %T Orvosi képfeldolgozás, Orvosi algoritmusok, Távérzékelés, mikroszkópia %A Attila Tanacs %A László Czúni %A Attila Tanacs %B Képi információ mérése %I Typotex Kiadó %C Budapest %P 57 - 105 %8 2011 %G hun %9 Book chapter %0 Thesis %D 2011 %T Parametric Estimation of Affine Deformations without Correspondences %A Csaba Domokos %I University of Szeged %C Szeged, Hungary %G eng %9 PhD Thesis %0 Journal Article %J ACTA CYBERNETICA-SZEGED %D 2011 %T Projection selection dependency in binary tomography %A László Gábor Varga %A Péter Balázs %A Antal Nagy %X

It has already been shown that the choice of projection angles can significantly influence the quality of reconstructions in discrete tomography. In this contribution we summarize and extend the previous results by explaining and demonstrating tile effects of projection selection dependency, in a set of experimental software tests. We perform reconstructions of software phantoms, by using different binary tomography reconstruction algorithms, from different equiangular and non-equiangular projections sets, under various conditions (i.e., when the objects to be reconstructed undergo slight topological changes, or the projection data is affected by noise) and compare the results with suitable approaches. Based on our observations, we reveal regularities in the resulting data and discuss possible consequences of such projection selection dependency in binary tomography.

 

%B ACTA CYBERNETICA-SZEGED %I University of Szeged, Institute of Informatics %C Szeged %V 20 %P 167 - 187 %8 2011 %@ 0324-721X %G eng %N 1 %9 Journal article %! ACTA CYBERN-SZEGED %0 Journal Article %J Acta Cybernetica %D 2011 %T Sufficient conditions for order-independency in sequential thinning %A Péter Kardos %X

The main issue of this paper is to introduce some conditions for template-based sequential thinning that are capable of producing the same skeleton for a given binary image, independent of the visiting order of object points. As an example, we introduce two order-independent thinning algorithms for 2D binary images that satisfy these conditions.

%B Acta Cybernetica %I University of Szeged %V 20 %P 87-100 %G eng %9 Journal Article %0 Book %D 2011 %T Számítógépes látás %A Zoltan Kato %A László Czúni %I Typotex Kiadó %C Budapest %8 2011 %G hun %9 Book %0 Conference Paper %B Informatika a felsőoktatásban 2011 konferencia %D 2011 %T Tehetséggondozó program a Szegedi Tudományegyetem Informatikai Tanszékcsoport BSc szakjain %A Péter Balázs %A Zoltán L Németh %E László Cser %E Miklós Herdon %B Informatika a felsőoktatásban 2011 konferencia %I Debreceni Egyetem Informatikai Kar %C Debrecen %P 905 - 912 %8 Aug 2011 %G hun %9 Conference paper %0 Journal Article %J GRAPHICAL MODELS %D 2011 %T Thinning combined with iteration-by-iteration smoothing for 3D binary images %A Gábor Németh %A Péter Kardos %A Kálmán Palágyi %X

In this work we present a new thinning scheme for reducing the noise sensitivity of 3D thinning algorithms. It uses iteration-by-iteration smoothing that removes some border points that are considered as extremities. The proposed smoothing algorithm is composed of two parallel topology preserving reduction operators. An efficient implementation of our algorithm is sketched and its topological correctness for (26, 6) pictures is proved. © 2011 Elsevier Inc. All rights reserved.

%B GRAPHICAL MODELS %V 73 %P 335 - 345 %8 Nov 2011 %@ 1524-0703 %G eng %N 6 %9 Journal article %! GRAPH MODELS %R 10.1016/j.gmod.2011.02.001 %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %D 2011 %T A topológia-megőrzés elegendő feltételein alapuló 3D párhuzamos vékonyító algoritmusok %A Gábor Németh %A Péter Kardos %A Kálmán Palágyi %E Zoltan Kato %E Kálmán Palágyi %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %I NJSZT %C Szeged %P 190 - 205 %8 Jan 2011 %G hun %U http://www.inf.u-szeged.hu/kepaf2011/pdfs/S05_02.pdf %9 Conference paper %0 Book Section %B Combinatorial Image Analysis (IWCIA) %D 2011 %T On topology preservation for hexagonal parallel thinning algorithms %A Péter Kardos %A Kálmán Palágyi %E Jake K Aggarwal %E Reneta P Barneva %E Valentin E Brimkov %E Kostadin N Koroutchev %E Elka R Korutcheva %X

Topology preservation is the key concept in parallel thinning algorithms on any sampling schemes. This paper establishes some sufficient conditions for parallel thinning algorithms working on hexagonal grids (or triangular lattices) to preserve topology. By these results, various thinning (and shrinking to a residue) algorithms can be verified. To illustrate the usefulness of our sufficient conditions, we propose a new parallel thinning algorithm and prove its topological correctness. © 2011 Springer-Verlag Berlin Heidelberg.

%B Combinatorial Image Analysis (IWCIA) %S Lecture Notes in Computer Science %I Springer Verlag %C Madrid, Spain %P 31 - 42 %8 May 2011 %@ 978-3-642-21072-3 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-21073-0_6 %0 Journal Article %J INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY %D 2011 %T Topology Preserving Parallel Thinning Algorithms %A Gábor Németh %A Kálmán Palágyi %X

Thinning is an iterative object reduction technique for extracting medial curves from binary objects. During a thinning process, some border points that satisfy certain topological and geometric constraints are deleted in iteration steps. Parallel thinning algorithms are composed of parallel reduction operators that delete a set of object points simultaneously. This article presents 21 parallel thinning algorithms for (8,4) binary pictures that are derived from the sufficient conditions for topology preservation accommodated to the three parallel thinning approaches. © 2011 Wiley Periodicals, Inc.

%B INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY %I Wiley Periodicals, Inc. %V 21 %P 37 - 44 %8 Feb 2011 %@ 0899-9457 %G eng %N 1 %9 Journal article %! INT J IMAG SYST TECH %R 10.1002/ima.20272 %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %D 2011 %T Vetületi irányfüggőség a bináris tomográfiában %A László Gábor Varga %A Péter Balázs %A Antal Nagy %E Zoltan Kato %E Kálmán Palágyi %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2011 %I NJSZT %C Szeged %P 92 - 105 %8 Jan 2011 %G hun %9 Conference paper %0 Conference Proceedings %B Magyar Számítógépes Nyelvészeti Konferencia %D 2011 %T VIII. Magyar Számítógépes Nyelvészeti Konferencia %E Attila Tanacs %E Veronika Vincze %B Magyar Számítógépes Nyelvészeti Konferencia %I Szegedi Tudományegyetem %C Szeged %8 Dec 2011 %@ 978-963-306-121-3 %G eng %U http://www.inf.u-szeged.hu/mszny2011/ %9 Conference proceedings %0 Book Section %B European Conference on Computer Vision (ECCV) %D 2010 %T Affine puzzle: Realigning deformed object fragments without correspondences %A Csaba Domokos %A Zoltan Kato %E Kostas Daniilidis %E Petros Maragos %E Nikos Paragios %X

This paper is addressing the problem of realigning broken objects without correspondences. We consider linear transformations between the object fragments and present the method through 2D and 3D affine transformations. The basic idea is to construct and solve a polynomial system of equations which provides the unknown parameters of the alignment. We have quantitatively evaluated the proposed algorithm on a large synthetic dataset containing 2D and 3D images. The results show that the method performs well and robust against segmentation errors. We also present experiments on 2D real images as well as on volumetric medical images applied to surgical planning. © 2010 Springer-Verlag.

%B European Conference on Computer Vision (ECCV) %S Lecture Notes in Computer Science %I Springer %C Crete, Greece %P 777 - 790 %8 Sep 2010 %@ 978-3-642-15551-2 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-15552-9_56 %0 Generic %D 2010 %T Angular Stable Locking System. Milestone in IM nailing? ASLS %A Endre Varga %A Balázs Erdőhelyi %8 2010/// %G eng %0 Journal Article %J ALKALMAZOTT MATEMATIKAI LAPOK %D 2010 %T Bejárásfüggetlen szekvenciális vékonyítás %A Péter Kardos %A Gábor Németh %A Kálmán Palágyi %B ALKALMAZOTT MATEMATIKAI LAPOK %V 27 %P 17 - 40 %8 2010 %@ 0133-3399 %G eng %N 1 %9 Journal article %! ALKALMAZOTT MATEMATIKAI LAPOK %0 Conference Paper %B Conference of PhD Students in Computer Science. Volume of Extended Abstracts %D 2010 %T Binary tomographic reconstruction with an object-based evolutionary algorithm %A Mihály Gara %A Péter Balázs %B Conference of PhD Students in Computer Science. Volume of Extended Abstracts %I University of Szeged %C Szeged %P 31 %8 June 2010 %G eng %9 Abstract %0 Book Section %B Computational Modeling of Objects Represented in Images %D 2010 %T Direction-dependency of a binary tomographic reconstruction algorithm %A László Gábor Varga %A Péter Balázs %A Antal Nagy %E Reneta P Barneva %E Valentin E Brimkov %E Herbert A Hauptman %E Renato M Natal Jorge %E João Manuel R S Tavares %X

We study how the quality of an image reconstructed by a binary tomographic algorithm depends on the direction of the observed object in the scanner, if only a few projections are available. To do so we conduct experiments on a set of software phantoms by reconstructing them form different projection sets using an algorithm based on D.C. programming (a method for minimizing the difference of convex functions), and compare the accuracy of the corresponding reconstructions by two suitable approaches. Based on the experiments, we discuss consequences on applications arising from the field of non-destructive testing, as well.

 

%B Computational Modeling of Objects Represented in Images %S Lecture Notes in Computer Science %I Springer Verlag %C Buffalo, NY, USA %P 242 - 253 %8 May 2010 %@ 978-3-642-12711-3 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-12712-0_22 %0 Book Section %B IEEE International Conference on Image Processing (ICIP) %D 2010 %T Estimation of linear deformations of 3D objects %A Attila Tanacs %A Joakim Lindblad %A Nataša Sladoje %A Zoltan Kato %X

We propose a registration method to find affine transformations between 3D objects by constructing and solving an overdetermined system of polynomial equations. We utilize voxel coverage information for more precise object boundary description. An iterative solution enables us to easily adjust the method to recover e.g. rigid-body and similarity transformations. Synthetic tests show the advantage of the voxel coverage representation, and reveal the robustness properties of our method against different types of segmentation errors. The method is tested on a real medical CT volume. © 2010 IEEE.

%B IEEE International Conference on Image Processing (ICIP) %I IEEE %C Hong Kong, Hong Kong %P 153 - 156 %8 Sep 2010 %G eng %9 Conference paper %0 Journal Article %J MEDICAL IMAGE ANALYSIS %D 2010 %T Glaucoma Risk Index: Automated glaucoma detection from color fundus images %A Rudriger Bock %A Jörg Meier %A László Gábor Nyúl %A Joachim Hornegger %A Georg Michelson %X

Glaucoma as a neurodegeneration of the optic nerve is one of themost common causes of blindness. Because revitalization of the degenerated nerve fibers of the optic nerve is impossible early detection of the disease is essential. This can be supported by a robust and automated mass-screening. We propose a novel automated glaucoma detection system that operates on inexpensive to acquire and widely used digital color fundus images. After a glaucoma specific preprocessing, different generic feature types are compressed by an appearance-based dimension reduction technique. Subsequently, a probabilistic two-stage classification scheme combines these features types to extract the novel Glaucoma Risk Index (GRI) that shows a reasonable glaucoma detection performance. On a sample set of 575 fundus images a classification accuracy of 80% has been achieved in a 5-fold cross-validation setup. The GRI gains a competitive area under ROC (AUC) of 88% compared to the established topography- based glaucoma probability score of scanning laser tomography with AUC of 87%. The proposed color fundus image-based GRI achieves a competitive and reliable detection performance on a low-priced modality by the statistical analysis of entire images of the optic nerve head.

%B MEDICAL IMAGE ANALYSIS %V 14 %P 471 - 481 %8 2010 %@ 1361-8415 %G eng %N 3 %9 Journal article %! MED IMAGE ANAL %0 Thesis %D 2010 %T Image analysis methods for medical research, diagnostic and therapeutic applications %A László Gábor Nyúl %8 2010 %G eng %9 PhD Thesis %0 Book Section %B Advances in Visual Computing %D 2010 %T Image enhancement by median filters in algebraic reconstruction methods: an experimental study %A Norbert Hantos %A Péter Balázs %E George Bebis %E Richard Boyle %E Bahram Parvin %E Darko Koracin %E Ronald Chung %E Riad Hammound %E Muhammad Hussain %E Tan Kar-Han %E Roger Crawfis %E Daniel Thalmann %E David Kao %E Lisa Avila %X

Algebraic methods for image reconstruction provide good solutions even if only few projections are available. However, they can create noisy images if the number of iterations or the computational time is limited. In this paper, we show how to decrease the effect of noise by using median filters during the iterations. We present an extensive study by applying filters of different sizes and in various times of the reconstruction process. Also, our test images are of different structural complexity. Our study concentrates on the ART and its discrete variant DART reconstruction methods.

 

%B Advances in Visual Computing %S Lecture Notes in Computer Science %I Springer Verlag %C Las Vegas, NV, USA %P 339 - 348 %8 Nov-Dec 2010 %@ 978-3-642-17276-2 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-17277-9_35 %0 Book Section %B 20th international conference on pattern recognition (ICPR 2010) %D 2010 %T Live cell segmentation in fluorescence microscopy via graph cut %A Milan Lesko %A Zoltan Kato %A Antal Nagy %A Imre Gombos %A Zsolt Török %A László Vígh %A László Vígh %E Aytul Ercil %X

We propose a novel Markovian segmentation model which takes into account edge information. By construction, the model uses only pairwise interactions and its energy is submodular. Thus the exact energy minima is obtained via a max-flow/min-cut algorithm. The method has been quantitatively evaluated on synthetic images as well as on fluorescence microscopic images of live cells. © 2010 IEEE.

%B 20th international conference on pattern recognition (ICPR 2010) %I IEEE %C Istanbul, Turkey %P 1485 - 1488 %8 Aug 2010 %@ 978-1-4244-7542-1 %G eng %9 Conference paper %M 11593484 %R 10.1109/ICPR.2010.367 %0 Book Section %B Workshop on Applications of Discrete Geometry in Mathematical Morphology %D 2010 %T Machine learning for supporting binary tomographic reconstruction %A Péter Balázs %A Mihály Gara %A Tamás Sámuel Tasi %E Ullrich Köthe %E Annick Montanvert %E Pierre Soille %B Workshop on Applications of Discrete Geometry in Mathematical Morphology %S Lecture Notes in Computer Science %I Springer %C Istambul, Turkey %P 101 - 105 %8 Aug 2010 %G eng %9 Conference paper %! LNCS %0 Conference Paper %B Conference of PhD Students in Computer Science. Volume of Extended Abstracts %D 2010 %T Object rotation effects on binary tomographic reconstruction %A László Gábor Varga %A Péter Balázs %A Antal Nagy %B Conference of PhD Students in Computer Science. Volume of Extended Abstracts %I University of Szeged %C Szeged, Hungary %P 76 %8 June 2010 %G eng %9 Abstract %0 Conference Paper %B Conference of PhD Students in Computer Science. Volume of Extended Abstracts %D 2010 %T Obtaining geometrical properties of binary images from two projections using neural networks %A Tamás Sámuel Tasi %A Péter Balázs %B Conference of PhD Students in Computer Science. Volume of Extended Abstracts %I University of Szeged %C Szeged, Hungary %P 69 %8 June 2010 %G eng %9 Abstract %0 Book Section %B Progress in Combinatorial Image Analysis %D 2010 %T Parallel Thinning Algorithms Based on Ronse's Sufficient Conditions for Topology Preservation %A Gábor Németh %A Kálmán Palágyi %E Petra Wiederhold %E Reneta P Barneva %B Progress in Combinatorial Image Analysis %I Scientific Research Publishing Inc. %C Singapore %P 183 - 194 %8 May 2010 %G eng %U http://rpsonline.com.sg/rpsweb/iwcia09.html %9 Book chapter %0 Journal Article %J PATTERN RECOGNITION %D 2010 %T Parametric estimation of affine deformations of planar shapes %A Csaba Domokos %A Zoltan Kato %B PATTERN RECOGNITION %V 43 %P 569 - 578 %8 March 2010 %@ 0031-3203 %G eng %N 3 %9 Journal article %! PATTERN RECOGN %R 10.1016/j.patcog.2009.08.013 %0 Book Section %B Advanced Concepts for Intelligent Vision Systems %D 2010 %T Projection selection algorithms for discrete tomography %A László Gábor Varga %A Péter Balázs %A Antal Nagy %E Jacques Blanc-Talon %E Don Bone %E Wilfried Philips %E Dan Popescu %E Paul Scheunders %B Advanced Concepts for Intelligent Vision Systems %I Springer Verlag %C Sydney, Australia %P 390 - 401 %8 Dec 2010 %G eng %9 Conference paper %0 Book Section %B Proceedings of the 6th International Conference on Signal Image Technology and Internet Based Systems, SITIS 2010 %D 2010 %T SITIS 2010: Track SIT editorial message: Signal and Image Technologies %A Albert Dipanda %A Zoltan Kato %E Albert Dipanda %E Richard Chbeir %E Kokou Yetongnon %B Proceedings of the 6th International Conference on Signal Image Technology and Internet Based Systems, SITIS 2010 %I IEEE Computer Society Press %C Kuala Lumpur %P XV %8 2010 %G eng %0 Conference Paper %B Proceedings of the International Conference on Signal Processing, Pattern Recognition and Applications (SPPRA) %D 2010 %T Topology preserving 2-subfield 3D thinning algorithms %A Gábor Németh %A Péter Kardos %A Kálmán Palágyi %E B Zagar %E A Kuijper %E H Sahbi %X

This paper presents a new family of 3D thinning algorithms for extracting skeleton-like shape features (i.e, centerline, medial surface, and topological kernel) from volumetric images. A 2-subfield strategy is applied: all points in a 3D picture are partitioned into two subsets which are alternatively activated. At each iteration, a parallel operator is applied for deleting some border points in the active subfield. The proposed algorithms are derived from Ma's sufficient conditions for topology preservation, and they use various endpoint characterizations.

%B Proceedings of the International Conference on Signal Processing, Pattern Recognition and Applications (SPPRA) %I IASTED ACTA Press %C Innsbruck, Austria %P 310 - 316 %8 Feb 2010 %G eng %9 Conference paper %0 Book Section %B Proceedings of the International Conference on Image Analysis and Recognition (ICIAR) %D 2010 %T Topology Preserving 3D Thinning Algorithms using Four and Eight Subfields %A Gábor Németh %A Péter Kardos %A Kálmán Palágyi %E Aurélio Campilho %E Mohamed Kamel %X

Thinning is a frequently applied technique for extracting skeleton-like shape features (i.e., centerline, medial surface, and topological kernel) from volumetric binary images. Subfield-based thinning algorithms partition the image into some subsets which are alternatively activated, and some points in the active subfield are deleted. This paper presents a set of new 3D parallel subfield-based thinning algorithms that use four and eight subfields. The three major contributions of this paper are: 1) The deletion rules of the presented algorithms are derived from some sufficient conditions for topology preservation. 2) A novel thinning scheme is proposed that uses iteration-level endpoint checking. 3) Various characterizations of endpoints yield different algorithms. © 2010 Springer-Verlag.

%B Proceedings of the International Conference on Image Analysis and Recognition (ICIAR) %S Lecture Notes in Computer Science %I Springer Verlag %C Póvoa de Varzim, Portugal %V 6111 %P 316 - 325 %8 June 2010 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-13772-3_32 %0 Book Section %B Proceedings of the Computational Modeling of Objects Represented in Images (CMORI) %D 2010 %T Topology Preserving Parallel Smoothing for 3D Binary Images %A Gábor Németh %A Péter Kardos %A Kálmán Palágyi %E Reneta P Barneva %E Valentin E Brimkov %E Herbert A Hauptman %E Renato M Natal Jorge %E João Manuel R S Tavares %X

This paper presents a new algorithm for smoothing 3D binary images in a topology preserving way. Our algorithm is a reduction operator: some border points that are considered as extremities are removed. The proposed method is composed of two parallel reduction operators. We are to apply our smoothing algorithm as an iteration-by-iteration pruning for reducing the noise sensitivity of 3D parallel surface-thinning algorithms. An efficient implementation of our algorithm is sketched and its topological correctness for (26,6) pictures is proved. © 2010 Springer-Verlag.

%B Proceedings of the Computational Modeling of Objects Represented in Images (CMORI) %I Springer Verlag %C Buffalo, USA %V 6026 %P 287 - 298 %8 May 2010 %G eng %9 Conference paper %R 10.1007/978-3-642-12712-0_26 %0 Book Section %B 16th IEEE International Conference on Image Processing (ICIP), 2009 %D 2009 %T Affine alignment of compound objects: A direct approach %A Csaba Domokos %A Zoltan Kato %X

A direct approach for parametric estimation of 2D affine deformations between compound shapes is proposed. It provides the result as a least-square solution of a linear system of equations. The basic idea is to fit Gaussian densities over the objects yielding covariant functions, which preserves the effect of the unknown transformation. Based on these functions, linear equations are constructed by integrating nonlinear functions over appropriate domains. The main advantages are: linear complexity, easy implementation, works without any time consuming optimization or established correspondences. Comparative tests show that it outperforms state-of-the-art methods both in terms of precision, robustness and complexity. ©2009 IEEE.

%B 16th IEEE International Conference on Image Processing (ICIP), 2009 %I IEEE %C Cairo, Egypt %P 169 - 172 %8 Nov 2009 %@ 978-1-4244-5653-6 %G eng %9 Conference paper %M 11150920 %R 10.1109/ICIP.2009.5414195 %0 Generic %D 2009 %T Affine Registration of Planar Shapes %A Zsolt Katona %A Csaba Domokos %A Zoltan Kato %X

This is the sample implementation and benchmark dataset of the binary image registration algorithm described in the following paper: Csaba Domokos and Zoltan Kato. Parametric Estimation of Affine Deformations of Planar Shapes. Pattern Recognition, 43(3):569--578, March 2010.

%8 2009/// %G eng %U http://www.inf.u-szeged.hu/~kato/software/affbinregdemo.html %0 Journal Article %J DISCRETE APPLIED MATHEMATICS %D 2009 %T A benchmark set for the reconstruction of hv-convex discrete sets %A Péter Balázs %B DISCRETE APPLIED MATHEMATICS %I Elsevier %V 157 %P 3447 - 3456 %8 Aug 2009 %@ 0166-218X %G eng %N 16 %9 Journal article %! DISCRETE APPL MATH %R 10.1016/j.dam.2009.02.019 %0 Journal Article %J IEEE TRANSACTIONS ON MEDICAL IMAGING %D 2009 %T Comparison and evaluation of methods for liver segmentation from CT datasets %A Tobias Heimann %A Brahm Van Ginneken %A Martin A Styner %A Yulia Arzhaeva %A Volker Aurich %A Christian Bauer %A Andreas Beck %A Christoph Becker %A Reinhardt Beichel %A György Bekes %A Fernando Bello %A Gerd Binnig %A Horst Bischof %A Alexander Bornik %A Peter MM Cashman %A Ying Chi %A Andres Córdova %A Benoit M Dawant %A Márta Fidrich %A Jacob D Furst %A Daisuke Furukawa %A Lars Grenacher %A Joachim Hornegger %A Dagmar Kainmüller %A Richard I Kitney %A Hidefumi Kobatake %A Hans Lamecker %A Thomas Lange %A Jeongjin Lee %A Brian Lennon %A Rui Li %A Senhu Li %A Hans-Peter Meinzer %A Gábor Németh %A Daniela S Raicu %A Anne-Mareike Rau %A Eva M Van Rikxoort %A Mikael Rousson %A László Ruskó %A Kinda A Saddi %A Günter Schmidt %A Dieter Seghers %A Akinobi Shimizu %A Pieter Slagmolen %A Erich Sorantin %A Grzegorz Soza %A Ruchaneewan Susomboon %A Jonathan M Waite %A Andreas Wimmer %A Ivo Wolf %X

This paper presents a comparison study between 10 automatic and six interactive methods for liver segmentation from contrast-enhanced CT images. It is based on results from the "MICCAI 2007 Grand Challenge" workshop, where 16 teams evaluated their algorithms on a common database. A collection of 20 clinical images with reference segmentations was provided to train and tune algorithms in advance. Participants were also allowed to use additional proprietary training data for that purpose. All teams then had to apply their methods to 10 test datasets and submit the obtained results. Employed algorithms include statistical shape models, atlas registration, level-sets, graph-cuts and rule-based systems. All results were compared to reference segmentations five error measures that highlight different aspects of segmentation accuracy. All measures were combined according to a specific scoring system relating the obtained values to human expert variability. In general, interactive methods reached higher average scores than automatic approaches and featured a better consistency of segmentation quality. However, the best automatic methods (mainly based on statistical shape models with some additional free deformation) could compete well on the majority of test images. The study provides an insight in performance of different segmentation approaches under real-world conditions and highlights achievements and limitations of current image analysis techniques. © 2009 IEEE.

%B IEEE TRANSACTIONS ON MEDICAL IMAGING %C Price, K., Anything you can do, I can do better (no you can't) (1986) Comput. Vis. Graph. Image Process, 36 (2-3), pp. 387-391;S. G. Armato, G. McLennan, M. F. McNitt-Gray, C. R. Meyer, D. Yankelevitz, D. R. Aberle, C. I. Henschke, E. A. Hoffman, E. A. Ka %V 28 %P 1251 - 1265 %8 Aug 2009 %@ 0278-0062 %G eng %N 8 %9 Journal article %! IEEE T MED IMAGING %R 10.1109/TMI.2009.2013851 %0 Journal Article %J ACTA CYBERNETICA-SZEGED %D 2009 %T Conference of PhD Students in Computer Science %A Kálmán Palágyi %B ACTA CYBERNETICA-SZEGED %V 19 %P 3 %8 2009/// %@ 0324-721X %G eng %N 1 %! ACTA CYBERN-SZEGED %0 Journal Article %J IEEE TRANSACTIONS ON IMAGE PROCESSING %D 2009 %T Detection of Object Motion Regions in Aerial Image Pairs with a Multilayer Markovian Model %A Csaba Benedek %A Tamas Sziranyi %A Zoltan Kato %A Josiane Zerubia %X

We propose a new Bayesian method for detectingthe regions of object displacements in aerial image pairs. We use a robust but coarse 2-D image registration algorithm. Our main challenge is to eliminate the registration errors from the extracted change map. We introduce a three-layer Markov Random Field (L3MRF) model which integrates information from two different features, and ensures connected homogenous regions in the segmented images. Validation is given on real aerial photos.

%B IEEE TRANSACTIONS ON IMAGE PROCESSING %I IEEE %V 18 %P 2303 - 2315 %8 2009 %@ 1057-7149 %G eng %N 10 %9 Journal article %! IEEE T IMAGE PROCESS %R 10.1109/TIP.2009.2025808 %0 Journal Article %J ALKALMAZOTT MATEMATIKAI LAPOK %D 2009 %T Emissziós Diszkrét Tomográfiai Módszerek Alkalmazása Faktorstruktúrákra. %A Antal Nagy %B ALKALMAZOTT MATEMATIKAI LAPOK %V 26 %P 329 - 350 %8 2009 %@ 0133-3399 %G eng %9 Journal article %! ALKALMAZOTT MATEMATIKAI LAPOK %0 Book Section %B Image Analysis %D 2009 %T An evolutionary approach for object-based image reconstruction using learnt priors %A Péter Balázs %A Mihály Gara %E Arnt-Borre Salberg %E Jon Yngve Hardeberg %E Robert Jenssen %X

In this paper we present a novel algorithm for reconstructingbinary images containing objects which can be described by some parameters. In particular, we investigate the problem of reconstructing binary images representing disks from four projections. We develop a genetic algorithm for this and similar problems. We also discuss how prior information on the number of disks can be incorporated into the reconstruction in order to obtain more accurate images. In addition, we present a method to exploit such kind of knowledge from the projections themselves. Experiments on artificial data are also conducted. © 2009 Springer Berlin Heidelberg.

%B Image Analysis %S Lecture Notes in Computer Science %I Springer-Verlag %C Oslo, Norway %P 520 - 529 %8 June 2009 %@ 978-3-642-02229-6 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-02230-2_53 %0 Book Section %B Proceedings of Discrete Geometry for Computer Imagery (DGCI) %D 2009 %T Fully Parallel 3D Thinning Algorithms based on Sufficient Conditions for Topology Preservation %A Kálmán Palágyi %A Gábor Németh %E Srecko Brlek %E Christophe Reutenauer %E Xavier Provençal %X

This paper presents a family of parallel thinning algorithms for extracting medial surfaces from 3D binary pictures. The proposed algorithms are based on sufficient conditions for 3D parallel reduction operators to preserve topology for (26,6) pictures. Hence it is self-evident that our algorithms are topology preserving. Their efficient implementation on conventional sequential computers is also presented. © 2009 Springer Berlin Heidelberg.

%B Proceedings of Discrete Geometry for Computer Imagery (DGCI) %I Springer Verlag %C Montreal, Quebec, Canada %P 481 - 492 %8 Sep 2009 %@ 978-3-642-04396-3 %G eng %9 Conference paper %R 10.1007/978-3-642-04397-0_41 %0 Book Section %B Graph-Based Representations in Pattern Recognition %D 2009 %T A Graph Based Data Model for Graphics Interpretation %A Endre Katona %B Graph-Based Representations in Pattern Recognition %S Lecture Notes in Computer Science %I Springer %C Venice, Italy %V 5534 %P 355-364 %8 October 2009 %G eng %9 Conference paper %R 10.1007/978-3-642-02124-4_8 %0 Journal Article %J PATTERN RECOGNITION %D 2009 %T A higher-order active contour model of a 'gas of circles' and its application to tree crown extraction %A Peter Horvath %A Ian Jermyn %A Zoltan Kato %A Josiane Zerubia %B PATTERN RECOGNITION %V 42 %P 699 - 709 %8 2009/// %@ 0031-3203 %G eng %N 5 %! PATTERN RECOGN %0 Journal Article %J PURE MATHEMATICS AND APPLICATIONS %D 2009 %T Learning connectedness and convexity of binary images from their projections %A Mihály Gara %A Tamás Sámuel Tasi %A Péter Balázs %B PURE MATHEMATICS AND APPLICATIONS %V 20 %P 27 - 48 %8 2009 %@ 1218-4586 %G eng %N 1-2 %9 Journal article %! PU.M.A PURE MATH APPL %0 Book Section %B 16th IEEE International Conference on Image Processing (ICIP) %D 2009 %T A Markov random field model for extracting near-circular shapes %A Tamás Blaskovics %A Zoltan Kato %A Ian Jermyn %X

We propose a binary Markov Random Field (MRF) model that assigns high probability to regions in the image domain consisting of an unknown number of circles of a given radius. We construct the model by discretizing the 'gas of circles' phase field model in a principled way, thereby creating an 'equivalent'MRF. The behaviour of the resultingMRF model is analyzed, and the performance of the new model is demonstrated on various synthetic images as well as on the problem of tree crown detection in aerial images. ©2009 IEEE.

%B 16th IEEE International Conference on Image Processing (ICIP) %I IEEE %C Cairo, Egypt %P 1073 - 1076 %8 Nov 2009 %@ 978-1-4244-5653-6 %G eng %9 Conference paper %R 10.1109/ICIP.2009.5413472 %0 Patent %D 2009 %T Method and system for automatically segmenting organs from three dimensional computed tomography images %A Márta Fidrich %A Eörs Máté %A László Gábor Nyúl %A Attila Kuba %A Bence Kiss %C Amerikai Egyesült Államok %V US20050907690 %8 2009 %G eng %N US7545979 %0 Book %D 2009 %T MIPPR 2009: Multispectral Image Acquisition and Processing %E Jayaram K Udupa %E Nong Sang %E László Gábor Nyúl %E Hengqing Tong %I SPIE %C Bellingham; Washington %V 7494 %8 Oct 2009 %@ 9780819478054 %G eng %9 Book %0 Journal Article %J INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE %D 2009 %T Multimodal Automated Glaucoma Detection Combining the Glaucoma Probability Score and the Glaucoma Risk Index %A Rudriger Bock %A Jörg Meier %A László Gábor Nyúl %A Joachim Hornegger %A Georg Michelson %X

Purpose:Fundus camera and Heidelberg Retina Tomograph (HRT) arecommonly used for reliable glaucoma diagnosis. Quantitative glaucoma scores, however, do not utilize both image content simultaneously. We propose the combination of topography and fundus image based indices for automated glaucoma detection which outperforms their sole application of either. Methods:The probabilistic values of topography based Glaucoma Probability Score (GPS) and our fundus image based Glaucoma Risk Index (GRI) are assembled to a two-dimensional feature space. In contrast to established methods the subsequent application of a probabilistic nu-Support Vector Machine classifier (nu = 0.5, kernel: radial basis function) uses both the topographic and the textural information to determine a final glaucoma probability. Instances labeled with a final probability greater than 0.5 are considered glaucomatous.For the evaluations in a 10-fold cross- validation setup, we took a sample set (mean age: 55.4 ± 10.9 years) of papilla images of 149 glaucomatous patients (FDT test time 67.4 ± 35.6 s) and 246 normals from the Erlangen Glaucoma Registry. The gold standard diagnosis was given by a glaucoma specialist based on an elaborate ophthalmological examination with ophthalmoscopy, visual field, IOP, FDT, and HRT II. The GPS was calculated by HRT device while papilla centered color fundus images (Kowa non-myd, FOV 22°) were used to calculate the GRI. Results:The classification of the GRI resulted in an area under ROC curve (AUC) of 0.81 with an F-measure of 0.71 for glaucomatous cases and 0.83 for normals. The GPS achieved an AUC of 0.86 while the F-measure for glaucoma was 0.74 (F-measure for healthy was 0.84).The combination of both indices clearly increased the AUC by 4% up to 0.9 compared to the sole application of the GPS. The F-measure for glaucomatous images was improved up to 0.76 (F-measure for healthy images was 0.86). Conclusions:The proposed combination of the topography based GPS and the fundus image based GRI shows superior performance compared to either index alone.Both indices utilize complementary information about the glaucoma disease. Consequently, this multimodal combined application of both indices is promising to reach a more reliable automated glaucoma detection performance. The approach can be used in large screening applications where an automated tool is essential to support the experts in finding glaucomatous eyes.

%B INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE %V 50 %P 324 %8 2009 %@ 0146-0404 %G eng %N 5 %9 Abstract %! INVEST OPHTH VIS SCI %0 Conference Paper %B 16th IEEE International Conference on Image Processing (ICIP) %D 2009 %T Nonlinear registration of binary shapes %A Jozsef Nemeth %A Csaba Domokos %A Zoltan Kato %X

A novel approach is proposed to estimate the parameters of a diffeomorphism that aligns two binary images. Classical approaches usually define a cost function based on a similarity metric and then find the solution via optimization. Herein, we trace back the problem to the solution of a system of non-linear equations which directly provides the parameters of the aligning transformation. The proposed method works without any time consuming optimization step or established correspondences. The advantage of our algorithm is that it is easy to implement, less sensitive to the strength of the deformation, and robust against segmentation errors. The efficiency of the proposed approach has been demonstrated on a large synthetic dataset as well as in the context of an industrial application. ©2009 IEEE.

%B 16th IEEE International Conference on Image Processing (ICIP) %I IEEE %C Cairo, Egypt %P 1101 - 1104 %8 Nov 2009 %@ 978-1-4244-5653-6 %G eng %9 Conference paper %R 10.1109/ICIP.2009.5413468 %0 Book Section %B Proceedings of the 6th International Symposium on Image and Signal Processing and Analysis %D 2009 %T Object subsampling strategies to improve computational performance %A András Hajdú %A Péter Veres %A Attila Tanacs %A Rorland Harangozó %E P Zinterhof %E Sven Lončarić %E A Uhl %E Alberto Carini %X

We investigate object simplification methods based on Centroidal Voronoi Tesselation (CVT) that share the possibility of great speed-ups in various scenarios. We propose Constrained CVT to sample points from the object boundary and the Region-based CVT to be able to subsample lower dimensional objects, as well. Moreover we introduce custom weight functions based on object properties. Thus, wecan be more specific on what are the important parts of the subsampled object. We also list several novel applications corresponding to the theoretical achivements presented. The advantages of applying the subsampling strategies are presented for registration, human detection, and the segmentation of the retinal vascular system, respectively. Quantitative results are shown to check the deterioration of the accuracy with the level of subsampling, and the computational gain. We also make comparisons with other naive (e.g. random) subsampling methods.

%B Proceedings of the 6th International Symposium on Image and Signal Processing and Analysis %I IEEE Press %C Salzburg %P 448 - 453 %8 Sep 2009 %G eng %9 Conference paper %0 Book Section %B Proceedings of the International Workshop on Combinatorial Image Analysis (IWCIA) %D 2009 %T An order-independent sequential thinning algorithm %A Péter Kardos %A Gábor Németh %A Kálmán Palágyi %E Petra Wiederhold %E Reneta P Barneva %X

Thinning is a widely used approach for skeletonization. Sequential thinning algorithms use contour tracking: they scan border points and remove the actual one if it is not designated a skeletal point. They may produce various skeletons for different visiting orders. In this paper, we present a new 2-dimensional sequential thinning algorithm, which produces the same result for arbitrary visiting orders and it is capable of extracting maximally thinned skeletons. © Springer-Verlag Berlin Heidelberg 2009.

%B Proceedings of the International Workshop on Combinatorial Image Analysis (IWCIA) %I Springer Verlag %C Playa del Carmen, Mexico %P 162 - 175 %8 Nov 2009 %@ 978-3-642-10208-0 %G eng %U http://link.springer.com/chapter/10.1007/978-3-642-10210-3_13 %9 Conference paper %R 10.1007/978-3-642-10210-3_13 %0 Book Section %B Combinatorial Image Analysis %D 2009 %T Reconstruction of canonical hv-convex discrete sets from horizontal and vertical projections %A Péter Balázs %E Petra Wiederhold %E Reneta P Barneva %X

The problem of reconstructing some special hv-convex discretesets from their two orthogonal projections is considered. In general, the problem is known to be NP-hard, but it is solvable in polynomial time if the discrete set to be reconstructed is also 8-connected. In this paper, we define an intermediate class - the class of hv-convex canonical discrete sets - and give a constructive proof that the above problem remains computationally tractable for this class, too. We also discuss some further theoretical consequences and present experimental results as well. © Springer-Verlag Berlin Heidelberg 2009.

%B Combinatorial Image Analysis %I Springer Verlag %C Berlin; Heidelberg; New York; London; Paris; Tokyo %P 280 - 288 %8 Nov 2009 %@ 978-3-642-10208-0 %G eng %9 Conference paper %R 10.1007/978-3-642-10210-3_22 %0 Book Section %B Image Analysis %D 2009 %T Recovering affine deformations of fuzzy shapes %A Attila Tanacs %A Csaba Domokos %A Nataša Sladoje %A Joakim Lindblad %A Zoltan Kato %E Arnt-Borre Salberg %E Jon Yngve Hardeberg %E Robert Jenssen %X

Fuzzy sets and fuzzy techniques are attracting increasing attention nowadays in the field of image processing and analysis. It has been shown that the information preserved by using fuzzy representation based on area coverage may be successfully utilized to improve precision and accuracy of several shape descriptors; geometric moments of a shape are among them. We propose to extend an existing binary shape matching method to take advantage of fuzzy object representation. The result of a synthetic test show that fuzzy representation yields smaller registration errors in average. A segmentation method is also presented to generate fuzzy segmentations of real images. The applicability of the proposed methods is demonstrated on real X-ray images of hip replacement implants. © 2009 Springer Berlin Heidelberg.

%B Image Analysis %S Lecture Notes in Computer Science %I Springer-Verlag %C Oslo, Norway %P 735 - 744 %8 June 2009 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-642-02230-2_75 %0 Book Section %B MIPPR 2009: Medical Imaging, Parallel Processing of Images, and Optimization Techniques %D 2009 %T Retinal image analysis for automated glaucoma risk evaluation %A László Gábor Nyúl %E Jianguo Liu %E Kunio Doi %E Aaron Fenster %E C S Chan %X

Images of the eye ground not only provide an insight toimportant parts of the visual system but also reflect the general state of health of the entire human body. Automatic retina image analysis is becoming an important screening tool for early detection of certain risks and diseases. Glaucoma is one of the most common causes of blindness and is becoming even more important considering the ageing society. Robust mass-screening may help to extend the symptom-free life of affected patients. Our research is focused on a novel automated classification system for glaucoma, based on image features from fundus photographs. Our new data-driven approach requires no manual assistance and does not depend on explicit structure segmentation and measurements. First, disease independent variations, such as nonuniform illumination, size differences, and blood vessels are eliminated from the images. Then, the extracted high-dimensional feature vectors are compressed via PCA and combined before classification with SVMs takes place. The technique achieves an accuracy of detecting glaucomatous retina fundus images comparable to that of human experts. The “vessel- free” images and intermediate output of the methods are novel representations of the data for the physicians that may provide new insight into and help to better understand glaucoma.

%B MIPPR 2009: Medical Imaging, Parallel Processing of Images, and Optimization Techniques %I SPIE %C Bellingham; Washington %P 74971C-1 - 74971C-9 %8 2009 %G eng %R 10.1117/12.851179 %0 Conference Paper %B International Conference on Computer Assisted Radiology and Surgery (CARS) %D 2009 %T Semi-automatic bone fracture reduction in surgical planning %A Balázs Erdőhelyi %A Endre Varga %X

The surgical intervention of complex bone fractures has to be planned very carefully, especially for such a complex region as the pelvic ring. The computer aided surgical planning is done before the actual surgery takes place and its main purpose is to gather more information about the dislocation of the bone fragments and to arrange the surgical implants to be inserted. With the help of finite element analysis even the biomechanical stability of the whole plan can be predicted. To create such a plan the following steps are performed. First, the CT dataset of the patient is segmented [1], which enables us to treat the different bones and broken fragments separately. Next the surface of this volumetric dataset is determined [2] and presented in a 3D environment. Since the fragments may have moved during the fracture, it is essential to move and rotate them back to their original anatomic position. Without this reduction, no implants can be inserted, since the final locations of the fragments are unknown. Previous solutions to the fracture reduction problem included moving the fragments with the mouse, or a special 3D haptic device. The former is not intuitive to use since the mouse is only 2D, and the later is expensive and still requires learning.

%B International Conference on Computer Assisted Radiology and Surgery (CARS) %I Springer Verlag %C Berlin, Germany %V 4 %P S98-S99 %G eng %9 Conference Paper %R 10.1007/s11548-009-0314-1 %0 Generic %D 2009 %T Supervised Color Image Segmentation in a Markovian Framework %A Mihály Gara %A Zoltan Kato %X

This is the sample implementation of a Markov random field based color image segmentation algorithm described in the following paper: Zoltan Kato, Ting Chuen Pong, and John Chung Mong Lee. Color Image Segmentation and Parameter Estimation in a Markovian Framework. Pattern Recognition Letters, 22(3-4):309--321, March 2001. Note that the current demo program implements only a supervised version of the segmentation method described in the above paper (i.e. parameter values are learned interactively from representative regions selected by the user). Otherwise, the program implements exactly the color MRF model proposed in the paper. Images are automatically converted from RGB to the perceptually uniform CIE-L*u*v* color space before segmentation.

%8 2009/// %G eng %U http://www.inf.u-szeged.hu/~kato/software/colormrfdemo.html %0 Generic %D 2009 %T VCP volar approach %A Endre Varga %A Balázs Erdőhelyi %8 2009/// %G eng %0 Journal Article %J THEORETICAL COMPUTER SCIENCE %D 2008 %T A 3D fully parallel surface-thinning algorithm %A Kálmán Palágyi %X

The thinning is an iterative layer by layer erosion until only the "skeletons" of the objects are left. This paper presents a thinning algorithm for extracting medial surfaces from 3D binary pictures. The strategy which is used is called fully parallel, which means that the same parallel operator is applied at each iteration. An efficient implementation of the proposed algorithm on conventional sequential computers is given and the topological correctness for (26, 6) binary pictures is proved. © 2008 Elsevier B.V. All rights reserved.

%B THEORETICAL COMPUTER SCIENCE %I Elsevier %C AHUJA N, 1997, IEEE T PATTERN ANAL, V19, P169ARCELLI C, 2006, LECT NOTES COMPUT SC, V4245, P555BERTRAND G, 1994, P SPIE C VISION GEOM, V2356, P113BERTRAND G, 1995, CR ACAD SCI I-MATH, V321, P1077BERTRAND G, 1995, P 5 INT C DISCR GEOM, P233BERTRAND G, %V 406 %P 119 - 135 %8 Oct 2008 %@ 0304-3975 %G eng %N 1-2 %9 Journal article %! THEOR COMPUT SCI %R 10.1016/j.tcs.2008.06.041 %0 Journal Article %J THEORETICAL COMPUTER SCIENCE %D 2008 %T Algorithms, automata, complexity and games Preface %A Joost K Batenburg %A Antal Nagy %A Maurice Nivat %B THEORETICAL COMPUTER SCIENCE %V 406 %P 1 %8 2008 %@ 0304-3975 %G eng %N 1-2 %9 Journal article %! THEOR COMPUT SCI %0 Journal Article %J ACTA CYBERNETICA-SZEGED %D 2008 %T On the ambiguity of reconstructing hv-convex binary matrices with decomposable configurations %A Péter Balázs %X

Reconstructing binary matrices from their row, column, diagonal, and antidiagonal sums (also called projections) plays a central role in discrete tomography. One of the main difficulties in this task is that in certain cases the projections do not uniquely determine the binary matrix. This can yield an extremely large number of (sometimes very different) solutions. This ambiguity can be reduced by having some prior knowledge about the matrix to be reconstructed. The main challenge here is to find classes of binary matrices where ambiguity is drastically reduced or even completely eliminated. The goal of this paper is to study the class of $hv$-convex matrices which have decomposable configurations from the viewpoint of ambiguity. First, we give a negative result in the case of three projections. Then, we present a heuristic for the reconstruction using four projections and analyze its performance in quality and running time.

%B ACTA CYBERNETICA-SZEGED %I University of Szeged %C Szeged, Hungary %V 18 %P 367 - 377 %8 2008 %@ 0324-721X %G eng %N 3 %9 Journal article %! ACTA CYBERN-SZEGED %0 Journal Article %J INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE %D 2008 %T Automated Glaucoma Detection From Color Fundus Photographs %A Rudriger Bock %A Jörg Meier %A László Gábor Nyúl %A Joachim Hornegger %A Georg Michelson %X

Purpose:The presentation of a novel fully automated system thatseparates glaucomatous from healthy cases based on digital fundus images. Methods:A pre-processing step eliminates certain disease independent variations such as illumination inhomogeneities, papilla size differences and vessel structures from the input images. In order to characterize glaucomatous changes, generic feature types (pixel intensities, frequency coefficients, histogram parameters, Gabor textures, spline coefficients) are extracted. In contrast to existing approaches, each feature vector is compressed by Principal Component Analysis. The classification of the transformed features is done by a state- of-the-art nu-Support Vector Machine.For the elaborate experimental evaluation of the proposed system architecture we took a large set of papilla-centered color fundus images of 100 glaucoma patients (FDT test time 67.25 ± 33.4 s) and 100 normals (overall mean age 57.0 ± 10.0 years) from the Erlangen Glaucoma Registry (Kowa non-myd, FOV 22,5°). The gold standard was given by an experienced ophthalmologist based on a complete ophthalmological examination with ophthalmoscopy, visual field, IOP, FDT, and HRT II. Results:Classification of compressed raw pixel intensities gained a success rate of 83% with a specificity of 0.72 and a sensitivity of 0.94 to detect glaucomatous cases. A success rate of 86% was achieved by using spline coefficients with a specificity of 0.78 and a sensitivity of 0.94 to detect glaucoma. The combination of both features slightly increased specificity to 0.82 (sensitivity = 0.92). The kappa statistic of 0.74 states a robust classification scheme. Conclusions:The proposed algorithm achieves a robust and competitive glaucoma detection rate. It is comparable to known methods applied to topographic papilla images and does not depend on segmentation-based measurements. For the first time, automated glaucoma detection is performed on color fundus images. Thus, fundus photography is an appropriate modality for computer-assisted glaucoma screening.

%B INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE %V 49 %P 1863 %8 2008 %@ 0146-0404 %G eng %N 5 %9 Journal article %! INVEST OPHTH VIS SCI %0 Book Section %B Image Analysis and Recognition %D 2008 %T Binary image registration using covariant gaussian densities %A Csaba Domokos %A Zoltan Kato %E Aurélio Campilho %X

We consider the estimation of 2D affine transformations aligning a known binary shape and its distorted observation. The classical way to solve this registration problem is to find correspondences between the two images and then compute the transformation parameters from these landmarks. In this paper, we propose a novel approach where the exact transformation is obtained as a least-squares solution of a linear system. The basic idea is to fit a Gaussian density to the shapes which preserves the effect of the unknown transformation. It can also be regarded as a consistent coloring of the shapes yielding two rich functions defined over the two shapes to be matched. The advantage of the proposed solution is that it is fast, easy to implement, works without established correspondences and provides a unique and exact solution regardless of the magnitude of transformation. © 2008 Springer-Verlag Berlin Heidelberg.

%B Image Analysis and Recognition %S Lecture Notes in Computer Science %I Springer %C Póvoa de Varzim, Portugal %P 455 - 464 %8 June 2008 %@ 978-3-540-69811-1 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-540-69812-8_45 %0 Conference Paper %B Proceedings of the Eight World Conference WCNR-8 %D 2008 %T Comparison Radiography and Tomography Possibilities of FRM-II (20 MW) and Budapest (10 MW) Research Reactor %A Márton Balaskó %A Attila Kuba %A Attila Tanacs %A Zoltán Kiss %A Antal Nagy %A Burkhard Schillinger %E Muhammed Arif %B Proceedings of the Eight World Conference WCNR-8 %P 18–27 %8 October %0 Book Section %B Proceedings of the Advanced Concepts for Intelligent Vision Systems %D 2008 %T Decision trees in binary tomography for supporting the reconstruction of hv-convex connected images %A Péter Balázs %A Mihály Gara %X

In binary tomography, several algorithms are known for reconstructing binary images having some geometrical properties from their projections. In order to choose the appropriate reconstruction algorithm it is necessary to have a priori information of the image to be reconstructed. In this way we can improve the speed and reduce the ambiguity of the reconstruction. Our work is concerned with the problem of retrieving geometrical information from the projections themselves. We investigate whether it is possible to determine geometric features of binary images if only their projections are known. Most of the reconstruction algorithms based on geometrical information suppose $hv$-convexity or connectedness about the image to be reconstructed. We investigate those properties in detail, and also the task of separating 4- and 8-connected images. We suggest decision trees for the classification, and show some preliminary experimental results of applying them for the class of $hv$-convex and connected discrete sets.

%B Proceedings of the Advanced Concepts for Intelligent Vision Systems %S Lecture Notes in Computer Science %I Springer %C Juan-les-Pins, France %V 5259 %P 433-443 %8 Oct 2008 %G eng %9 Conference Paper %! LNCS %R 10.1007/978-3-540-88458-3_39 %0 Conference Paper %B Conference of PhD Students in Computer Science. Volume of Extended Abstracts %D 2008 %T Determination of geometric features of binary images from their projections by using decision trees %A Mihály Gara %A Péter Balázs %E Kálmán Palágyi %E Balázs Bánhelyi %E Tamás Gergely %E István Matievics %B Conference of PhD Students in Computer Science. Volume of Extended Abstracts %I University of Szeged %C Szeged, Hungary %P 26 %8 July 2008 %G eng %9 Abstract %0 Journal Article %J INTERNATIONAL JOURNAL OF SHAPE MODELLING %D 2008 %T Discrete tomographic reconstruction of binary images with disjoint components using shape information %A Péter Balázs %X
We present a general framework for reconstructing binary images with disjoint components from the horizontal and vertical projections. We develop a backtracking algorithm that works for binary images having components from an arbitrary class. Thus, a priori knowledge about the components of the image to be reconstructed can be incorporated into the reconstruction process. In addition, we show how to extend the algorithm to obtain a branch-and-bound scheme useful to reconstruct images satisfying some further properties (for example similarity to a model image) as much as possible. Experimental results are also presented.
 

 

%B INTERNATIONAL JOURNAL OF SHAPE MODELLING %I World Scientific %V 14 %P 189 - 207 %8 Dec 2008 %@ 0218-6543 %G eng %N 2 %9 Journal article %! INT J SHAPE MODEL %R 10.1142/S0218654308001142 %0 Journal Article %J INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE %D 2008 %T The Erlanger Glaucoma Matrix - A Visualization Approach Towards Optimal Glaucomatous Optic Nerve Head Image Presentation %A Jörg Meier %A Rudriger Bock %A C Forman %A László Gábor Nyúl %A Joachim Hornegger %A Georg Michelson %X

Purpose:Presentation of a two-dimensional visualization approachfor intuitive and reliable glaucoma diagnosis and for setting a current observation into a relationship with pre-diagnosed data. Methods:We present a new matrix visualization technique for digital optic nerve head images. The matrix is filled with 300 pre-diagnosed reference images which show different papilla sizes and varying stages of glaucoma disease. In matrix rows the samples range from healthy ones to advanced glaucoma cases. In matrix columns the papillas are ordered by the size of the optic nerve head. The approach generalizes such that the samples can be ordered by additional criteria, too, e. g. subjects' age or anamnestic risk factors. Furthermore arbitrary image modalities and image numbers can be incorporated. Results:The glaucoma classification of a single image is difficult even for experts. Our proposed visualization provides an intuitive way for neighborhood comparisons of optic nerve head images. It allows to evaluate an image in the context of given pre-diagnosed reference samples. By the two-dimensional presentation one can study disease-dependent changes separate from other variations. Glaucoma progression can be observed separated from size variations. Thus, it supports diagnosis even in problematic cases such as macropapillas. The trustworthiness of physicians' diagnosis can be improved. Conclusions:Our approach gives insights on glaucomatous optic nerve appearance in relation to varying papilla sizes. The novel visualization of a single image within the context of other images is considered as an important tool for learning and training medical glaucoma detection. This approach visualizes computer calculated risk estimations by presenting the result within context of given gold-standard images. In contrast to pure classification systems our method does not come up with a hard decision but explains the relationship to similar pre- diagnosed cases.

%B INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE %I Arvo %V 49 %P 1893 %8 May 2008 %@ 0146-0404 %G eng %N 5 %9 Journal article %! INVEST OPHTH VIS SCI %0 Journal Article %J JOURNAL OF CRANIO-MAXILLOFACIAL SURGERY %D 2008 %T Finite element analysis of mandible virtual model %A Endre Varga %A Zoltán Raskó %A Balázs Erdőhelyi %A L Seres %A J Piffko %B JOURNAL OF CRANIO-MAXILLOFACIAL SURGERY %I Elsevier %V 36 %P S204 %8 2008 %@ 1010-5182 %G eng %N Suppl 1 %9 Journal article %! J CRANIO MAXILL SURG %R 10.1016/S1010-5182(08)71931-0 %0 Journal Article %J THEORETICAL COMPUTER SCIENCE %D 2008 %T A framework for generating some discrete sets with disjoint components by using uniform distributions %A Péter Balázs %B THEORETICAL COMPUTER SCIENCE %I Elsevier %V 406 %P 15 - 23 %8 Oct 2008 %@ 0304-3975 %G eng %N 1-2 %9 Journal article %! THEOR COMPUT SCI %R 10.1016/j.tcs.2008.06.010 %0 Journal Article %J MEDICAL PHYSICS %D 2008 %T Geometrical model-based segmentation of the organs of sight on CT images %A György Bekes %A Eörs Máté %A László Gábor Nyúl %A Attila Kuba %A Márta Fidrich %X

Segmentation of organs of sight such as the eyeballs, lenses,and optic nerves is a time consuming task for clinicians. The small size of the organs and the similar density of the surrounding tissues make the segmentation difficult. We developed a new algorithm to segment these organs with minimal user interaction. The algorithm needs only three seed points to fit an initial geometrical model to start an effective segmentation. The clinical evaluation shows that the output of our method is useful in clinical practice.

%B MEDICAL PHYSICS %V 35 %P 735 - 743 %8 Feb 2008 %@ 0094-2405 %G eng %N 2 %9 Journal article %! MED PHYS %0 Journal Article %J THEORETICAL COMPUTER SCIENCE %D 2008 %T In Memoriam Attila Kuba (1953-2006) %A Joost K Batenburg %A Antal Nagy %A Maurice Nivat %B THEORETICAL COMPUTER SCIENCE %C KUBA A, PUBLICATION LIST %V 406 %P 2 - 7 %8 2008 %@ 0304-3975 %G eng %N 1-2 %9 Journal article %! THEOR COMPUT SCI %0 Book Section %B Analysis of Biomedical Signals and Images %D 2008 %T Novel Visualization Approach of an Automated Image Based Glaucoma Risk Index for Intuitive Diagnosis %A Jörg Meier %A Rudriger Bock %A László Gábor Nyúl %A Joachim Hornegger %A Georg Michelson %E Jiří Jan %E Jiří Konzuplik %E Ivo Provazník %X

Glaucoma is one of the most common causes for blindnessworldwide. Screening is adequate to detect glaucoma at an early stage. Although it is supported by computer assisted tools no further information from former clinical studies is incorporated. We devised a novel visualization tool that presents additional comparative image data for the diagnosis process. Automated computation of a glaucoma risk index on color fundus photographs is used to initially position an undiagnosed image in reference data. The index achieves a competitive glaucoma detection rate. The combination of the automated risk index and the new visualization technique is an important tool towards a faster and more reliable diagnosis of glaucoma.

%B Analysis of Biomedical Signals and Images %I Brno University of Technology %C Brno %P 205 - 209 %8 2008/// %G eng %0 Book Section %B Combinatorial Image Analysis %D 2008 %T On the number of hv-convex discrete sets %A Péter Balázs %E Valentin E Brimkov %E Reneta P Barneva %E Herbert A Hauptman %X

One of the basic problems in discrete tomography is thereconstruction of discrete sets from few projections. Assuming that the set to be reconstructed fulfills some geometrical properties is a commonly used technique to reduce the number of possibly many different solutions of the same reconstruction problem. The class of hv-convex discrete sets and its subclasses have a well-developed theory. Several reconstruction algorithms as well as some complexity results are known for those classes. The key to achieve polynomial-time reconstruction of an hv- convex discrete set is to have the additional assumption that the set is connected as well. This paper collects several statistics on hv-convex discrete sets, which are of great importance in the analysis of algorithms for reconstructing such kind of discrete sets. © 2008 Springer-Verlag Berlin Heidelberg.

%B Combinatorial Image Analysis %S Lecture Notes in Computer Science %I Springer Verlag %C Buffalo, NY, USA %P 112 - 123 %8 Apr 2008 %@ 978-3-540-78274-2 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-540-78275-9_10 %0 Book Section %B Proceedings of the IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %D 2008 %T Parametric estimation of affine deformations of binary images %A Csaba Domokos %A Zoltan Kato %A Joseph M Francos %X

We consider the problem of planar object registration on binary images where the aligning transformation is restricted to the group of affine transformations. Previous approaches usually require established correspondences or the solution of nonlinear optimization problems. Herein we show that it is possible to formulate the problem as the solution of a system of up to third order polynomial equations. These equations are constructed in a simple way using some basic geometric information of binary images. It does not need established correspondences nor the solution of complex optimization problems. The resulting algorithm is fast and provides a direct solution regardless of the magnitude of transformation. ©2008 IEEE.

%B Proceedings of the IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) %I IEEE %C Las Vegas, NV, USA %P 889 - 892 %8 March 2008 %@ 978-1-4244-1483-3 %G eng %9 Conference paper %M 9973096 %R 10.1109/ICASSP.2008.4517753 %0 Book Section %B Advances in Visual Computing %D 2008 %T Reconstruction of binary images with few disjoint components from two projections %A Péter Balázs %E George Bebis %E Richard Boyle %E Bahram Parvin %E Darko Koracin %E Paolo Remagnino %E Fatih Porikli %E Jörg Peters %E James Klosowski %E Laura Arns %E Yu Ka Chun %E Theresa-Marie Rhyne %E Laura Monroe %X

We present a general framework for reconstructing binary imageswith few disjoint components from the horizontal and vertical projections. We develop a backtracking algorithm that works for binary images having components from an arbitrary class. Thus, a priori information about the components of the image to be reconstructed can be incorporated into the reconstruction process. In addition, we can keep control over the number of components which can increase the speed and accuracy of the reconstruction. Experimental results are also presented. © 2008 Springer Berlin Heidelberg.

%B Advances in Visual Computing %S Lecture Notes in Computer Science %I Springer Verlag %C Las Vegas, NV, USA %P 1147 - 1156 %8 Dec 2008 %@ 978-3-540-89645-6 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-540-89646-3_114 %0 Journal Article %J IMAGE AND VISION COMPUTING %D 2008 %T Segmentation of color images via reversible jump MCMC sampling %A Zoltan Kato %B IMAGE AND VISION COMPUTING %I Elsevier %V 26 %P 361 - 371 %8 March 2008 %@ 0262-8856 %G eng %N 3 %9 Journal article %! IMAGE VISION COMPUT %R 10.1016/j.imavis.2006.12.004 %0 Book Section %B Computer Vision Systems %D 2008 %T Skeletonization based on metrical neighborhood sequences %A Attila Fazekas %A Kálmán Palágyi %A György Kovács %A Gábor Németh %E Antonios Gasteratos %E Markus Vincze %E John K Tsotsos %X

Skeleton is a shape descriptor which summarizes the general formof objects. It can be expressed in terms of the fundamental morphological operations. The limitation of that characterization is that its construction based on digital disks such that cannot provide good approximation to the Euclidean disks. In this paper we define a new type of skeleton based on neighborhood sequences that is much closer to the Euclidean skeleton. A novel method for quantitative comparison of skeletonization algorithms is also proposed. © 2008 Springer- Verlag Berlin Heidelberg.

%B Computer Vision Systems %I Springer Verlag %C Santorini, Greece %P 333 - 342 %8 May 2008 %@ 978-3-540-79546-9 %G eng %9 Conference paper %R 10.1007/978-3-540-79547-6_32 %0 Conference Paper %B Proceedings of the Eight World Conference WCNR-8 %D 2008 %T Study of the Inner Structure of a Damaged Control Rod by Neutron and X-ray Radiography and Discrete Tomography %A Márton Balaskó %A Erzsébet Sváb %A Zoltán Kiss %A Attila Tanacs %A Antal Nagy %A Attila Kuba %E Muhammed Arif %B Proceedings of the Eight World Conference WCNR-8 %P 294–303 %8 October %0 Patent %D 2008 %T Systems and methods for segmenting an organ in a plurality of images %A Márta Fidrich %A Géza Makay %A Eörs Máté %A Emese Balogh %A Attila Kuba %A László Gábor Nyúl %A Judit Kanyó %C Amerikai Egyesült Államok %V US20040858241 %8 2008 %G eng %N US7388973 %0 Book Section %B Image Processing in Radiology %D 2008 %T Techniques of Virtual Dissection of the Colon Based on Spiral CT Data %A Erich Sorantin %A Emese Balogh %A Anna Vilanova Bartroli %A Kálmán Palágyi %A László Gábor Nyúl %A Franz Lindbichler %A Andrea Ruppert %E Emanuele Neri %E Davide Caramella %E Carlo Bartolozzi %X

Colorectal cancer represents the third most commonly diagnosedcancer and is the second leading cause of cancer deaths in the United States (Gazelle et al. 2000). In addition, colorectal cancer is responsible for about 11% of all new cancer cases per year (Gazelle et al. 2000). Five-year prognosis is about 90% for patients with localized disease compared to 60% if there is a regional spread and a drop to 10% in patients with distant metastasis (Gazelle et al. 2000). In the field of medicine there is a widely accepted opinion that most colorectal cancers arise from pre-existent adenomatous polyps (Johnson 2000). Therefore, different societies, such as the American Cancer Society, have proposed screening for colorectal cancer (Byers et al. 1997; Winawer et al. 1997). Today, different options exist for detection of colorectal cancer, including digital rectal examination, fecal occult blood testing, flexible and rigid sigmoidoscopy, barium enema and its variants, colonoscopy and recently computed tomography or magnetic resonance-based virtual colonography (Gazelle et al. 2000).

%B Image Processing in Radiology %I Springer-Verlag %C Berlin %P 257 - 268 %8 2008 %G eng %9 Book chapter %R 10.1007/978-3-540-49830-8_18 %0 Generic %D 2008 %T Virtual Planning Tool for Surgical Planning %A Endre Varga %A Balázs Erdőhelyi %8 2008/// %G eng %0 Journal Article %J INTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY %D 2007 %T 3D segmentation of liver, kidneys and spleen from CT images %A György Bekes %A László Gábor Nyúl %A Eörs Máté %A Attila Kuba %A Márta Fidrich %X

The clinicians often need to segment the abdominal organs forradiotherapy planning. Manual segmentation of these organs is very time-consuming, therefore automated methods are desired. We developed a semi-automatic segmentation method to outline liver, spleen and kidneys. It works on CT images without contrast intake that are acquired with a routine clinical protocol. From an initial surface around a user defined seed point, the segmentation of the organ is obtained by an active surface algorithm. Pre- and post-processing steps are used to adapt the general method for specific organs. The evaluation results show that the accuracy of our method is about 90%, which can be further improved with little manual editing, and that the precision is slightly higher than that of manual contouring. Our method is accurate, precise and fast enough to use in the clinical practice.

%B INTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY %V 2 %P S45 - S47 %8 June 2007 %@ 1861-6410 %G eng %N 1 SUPPL. %9 Jounal article %! INT J COMPUT ASSIST RADIOL SURG %0 Book Section %B Computer Analysis of Images and Patterns %D 2007 %T A 3-subiteration surface-thinning algorithm %A Kálmán Palágyi %E Walter G Kropatsch %E Martin Kampel %E Allan Hanbury %X

Thinning is an iterative layer by layer erosion for extractingskeleton. This paper presents an efficient parallel 3D thinning algorithm which produces medial surfaces. A three-subiteration strategy is proposed: the thinning operation is changed from iteration to iteration with a period of three according to the three deletion directions. © Springer-Verlag Berlin Heidelberg 2007.

%B Computer Analysis of Images and Patterns %S Lecture Notes in Computer Science %I Springer Verlag %C Vienna, Austria %P 628 - 635 %8 Aug 2007 %@ 978-3-540-74271-5 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-540-74272-2_78 %0 Book %B Advances in Discrete Tomography and Its Applications %D 2007 %T Advances in Discrete Tomography and Its Applications %A Gábor T. Herman %A Attila Kuba %X

Advances in Discrete Tomography and Its Applications is a unified presentation of new methods, algorithms, and select applications that are the foundations of multidimensional image reconstruction by discrete tomographic methods. The self-contained chapters, written by leading mathematicians, engineers, and computer scientists, present cutting-edge research and results in the field. Three main areas are covered: foundations, algorithms, and practical applications. Following an introduction that reports the recent literature of the field, the book explores various mathematical and computational problems of discrete tomography including new applications. Topics and Features: * introduction to discrete point X-rays * uniqueness and additivity in discrete tomography * network flow algorithms for discrete tomography * convex programming and variational methods * applications to electron microscopy, materials science, nondestructive testing, and diagnostic medicine Professionals, researchers, practitioners, and students in mathematics, computer imaging, biomedical imaging, computer science, and image processing will find the book to be a useful guide and reference to state-of-the-art research, methods, and applications.

%B Advances in Discrete Tomography and Its Applications %I Birkhauser %8 2007 %G eng %9 Book %0 Book Section %B 3rd Russian-Bavarian Conference on Bio-Medical Engineering, Proceedings %D 2007 %T Appearance-based Approach to Extract an Age-related Biomarker from Retinal Images %A Rudriger Bock %A Jörg Meier %A László Gábor Nyúl %A Simone Wärntges %A Georg Michelson %A Joachim Hornegger %E Joachim Hornegger %E Ernst W Mayr %E Sergey Schookin %E Hubertus Feußner %E Nassir Navab %E Yuri V. Gulyaev %E Kurt Höller %E Victor Ganzha %X

We present an appearance-based method that extracts a new age-related biomarker from retina images. The Principal Component Analysis is applied on intensity values of the illumination corrected green channel of fundus images. The algorithm does not use segmentation, is robust and shows a high range of reliability. It identified an age-related feature with a strong influence of the temporal parapapillary area and the optic nerve head. The feature correlates with chronological age of the participants and is significantly influenced by the appearance of cardiovascular risk factors such as smoking and hypertension, and thus it can be designated a biomarker. We extract and validate a medical parameter from retina images applying a purely data-driven approach without using any prior knowledge.

%B 3rd Russian-Bavarian Conference on Bio-Medical Engineering, Proceedings %I Friedrich-Alexander University Erlangen-Nuremberg %C Erlangen %V 1 %P 127 - 131 %8 2007 %G eng %9 Conference paper %0 Thesis %D 2007 %T Binary Tomography Using Geometrical Priors: Uniqueness and Reconstruction Results %A Péter Balázs %I University of Szeged %C Szeged, Hungary %8 2007 %G eng %9 PhD thesis %0 Book Section %B Pattern Recognition %D 2007 %T Classifying Glaucoma with Image-based Features from Fundus Photographs %A Rudriger Bock %A Jörg Meier %A Georg Michelson %A László Gábor Nyúl %A Joachim Hornegger %E Fred A Hamprecht %E Christoph Schnorr %E Bernd Jähne %X

Glaucoma is one of the most common causes of blindness and it isbecoming even more important considering the ageing society. Because healing of died retinal nerve fibers is not possible early detection and prevention is essential. Robust, automated mass-screening will help to extend the symptom-free life of affected patients. We devised a novel, automated, appearance based glaucoma classification system that does not depend on segmentation based measurements. Our purely data-driven approach is applicable in large-scale screening examinations. It applies a standard pattern recognition pipeline with a 2-stage classification step. Several types of image-based features were analyzed and are combined to capture glaucomatous structures. Certain disease independent variations such as illumination inhomogeneities, size differences, and vessel structures are eliminated in the preprocessing phase. The “vessel-free” images and intermediate results of the methods are novel representations of the data for the physicians that may provide new insight into and help to better understand glaucoma. Our system achieves 86 % success rate on a data set containing a mixture of 200 real images of healthy and glaucomatous eyes. The performance of the system is comparable to human medical experts in detecting glaucomatous retina fundus images.

%B Pattern Recognition %S Lecture Notes in Computer Science %I Springer Verlag %C Heidelberg %P 355 - 364 %8 Sep 2007 %@ 978-3-540-74933-2 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-540-74936-3_36 %0 Journal Article %J INTERNATIONAL JOURNAL OF GEOGRAPHICAL INFORMATION SCIENCE %D 2007 %T Contour line thinning and multigrid generation of raster-based digital elevation models %A Endre Katona %X

Thin plate spline interpolation is a widely used approach to generate a digital elevation model (DEM) from contour lines and scattered data. In practice, contour maps are scanned and vectorized, and after resampling in the target grid resolution, interpolation is performed. In this paper we demonstrate the limited accuracy of this process, and propose a high‐resolution processing method (without vectorization) that ensures maximum utilization of information in the source data. First, we discuss the mathematical background of thin plate spline interpolation, and explain the multigrid relaxation principle used to speed up convergence. After, we will show why fine tuning is necessary, especially when contour lines and elevation points are processed at the same time. Finally, our own contour thinning method that produces a significant reduction of elevation bias is described.

%B INTERNATIONAL JOURNAL OF GEOGRAPHICAL INFORMATION SCIENCE %I Taylor & Francis %V 21 %P 71 - 82 %8 Jan 2007 %@ 1365-8816 %G eng %N 1-2 %9 Journal article %! INT J GEOGR INF SCI %R 10.1080/13658810600816474 %0 Book Section %B ADVANCES IN DISCRETE TOMOGRAPHY AND ITS APPLICATIONS %D 2007 %T Decomposition Algorithms for Reconstructing Discrete Sets with Disjoint Components %A Péter Balázs %E Gábor T Herman %E Attila Kuba %X

The reconstruction of discrete sets from their projections is a frequently studied field in discrete tomography with applications in electron microscopy, image processing, radiology, and so on. Several efficient reconstruction algorithms have been developed for certain classes of discrete sets having some good geometrical properties. On the other hand, it has been shown that the reconstruction under certain circumstances can be very time-consuming, even NP-hard. In this chapter we show how prior information that the set to be reconstructed consists of several components can be exploited in order to facilitate the reconstruction. We present some general techniques to decompose a discrete set into components knowing only its projections and thus reduce the reconstruction of a general discrete set to the reconstruction of single components, which is usually a simpler task.

%B ADVANCES IN DISCRETE TOMOGRAPHY AND ITS APPLICATIONS %S Applied and Numerical Harmonic Analysis %I Birkhauser Boston %C Cambridge %P 153 - 173 %8 2007 %@ 978-0-8176-3614-2 %G eng %9 Book chapter %R 10.1007/978-0-8176-4543-4_8 %0 Journal Article %J IMAGE AND VISION COMPUTING %D 2007 %T A decomposition technique for reconstructing discrete sets from four projections %A Péter Balázs %X

The reconstruction of discrete sets from four projections is in general an NP-hard problem. In this paper we study the class of decomposable discrete sets and give an efficient reconstruction algorithm for this class using four projections. It is also shown that an arbitrary discrete set which is Q-convex along the horizontal and vertical directions and consists of several components is decomposable. As a consequence of decomposability we get that in a subclass of hv-convex discrete sets the reconstruction from four projections can also be solved in polynomial time. Possible extensions of our method are also discussed.

%B IMAGE AND VISION COMPUTING %I Elsevier %V 25 %P 1609 - 1619 %8 Oct 2007 %@ 0262-8856 %G eng %N 10 %9 Journal article %! IMAGE VISION COMPUT %R 10.1016/j.imavis.2006.06.015 %0 Book Section %B Advances in Discrete Tomography and Its Applications %D 2007 %T Discrete Tomography Methods for Nondestructive Testing. %A Joachim Baumann %A Zoltán Kiss %A Sven Krimmel %A Attila Kuba %A Antal Nagy %A Lajos Rodek %A Burkhard Schillinger %A Juergen Stephan %E Gábor T Herman %E Attila Kuba %X

The industrial nondestructive testing (NDT) of objects seems to be an ideal application of discrete tomography. In many cases, the objects consist of known materials, and a lot of a priori information is available (e.g., the description of an ideal object, which is similar to the actual one under investigation). One of the frequently used methods in NDT is to take projection images of the objects by some transmitting ray (e.g., X- or neutron-ray) and reconstruct the cross sections. But it can happen that only a few number of projections can be collected, because of long and/or expensive data acquisition, or the projections can be collected only from a limited range of directions. The chapter describes two DT reconstruction methods used in NDT experiments, shows the results of a DT procedure applied in the reconstruction of oblong objects having projections only from a limited range of angles, and, finally, suggests a few further possible NDT applications of DT.

 

%B Advances in Discrete Tomography and Its Applications %S Applied and Numerical Harmonic Analysis %I Birkhauser %P 303 - 332 %8 2007 %@ 978-0-8176-3614-2 %G eng %9 Book Chapter %R 10.1007/978-0-8176-4543-4_14 %0 Book Section %B Computer Analysis of Images and Patterns %D 2007 %T Effects of Preprocessing Eye Fundus Images on Appearance Based Glaucoma Classification %A Jörg Meier %A Rudriger Bock %A Georg Michelson %A László Gábor Nyúl %A Joachim Hornegger %E Walter G Kropatsch %E Martin Kampel %E Allan Hanbury %X

Early detection of glaucoma is essential for preventing one ofthe most common causes of blindness. Our research is focused on a novel automated classification system based on image features from fundus photographs which does not depend on structure segmentation or prior expert knowledge. Our new data driven approach that needs no manual assistance achieves an accuracy of detecting glaucomatous retina fundus images compareable to human experts. In this paper, we study image preprocessing methods to provide better input for more reliable automated glaucoma detection. We reduce disease independent variations without removing information that discriminates between images of healthy and glaucomatous eyes. In particular, nonuniform illumination is corrected, blood vessels are inpainted and the region of interest is normalized before feature extraction and subsequent classification. The effect of these steps was evaluated using principal component analysis for dimension reduction and support vector machine as classifier.

%B Computer Analysis of Images and Patterns %S Lecture Notes in Computer Science %I Springer Verlag %C Berlin; Heidelberg %P 165 - 172 %8 Aug 2007 %@ 978-3-540-74271-5 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-540-74272-2_21 %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2007 %D 2007 %T Efficient Implementation of 3D Thinning Algorithms %A Kálmán Palágyi %E Attila Fazekas %E András Hajdú %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2007 %I Képfeldolgozók és Alakfelismerők Társasága %C Debrecen %P 266 - 274 %8 Jan 2007 %G eng %0 Book Section %B ADVANCES IN DISCRETE TOMOGRAPHY AND ITS APPLICATIONS %D 2007 %T Emission discrete tomography. %A Elena Barcucci %A Andrea Frosini %A Attila Kuba %A Antal Nagy %A Simone Rinaldi %A Martin Samal %A Steffen Zopf %E Gábor T Herman %E Attila Kuba %X

Three problems of emission discrete tomography (EDT) are presented. The first problem is the reconstruction of measurable plane sets from two absorbed projections. It is shown that Lorentz theorems can be generalized to this case. The second is the reconstruction of binary matrices from their absorbed row and columns sums if the absorption coefficient is μ0 = log((1+v/5)/2). It is proved that the reconstruction in this case can be done in polynomial time. Finally, a possible application of EDT in single photon emission computed tomography (SPECT) is presented: Dynamic structures are reconstructed after factor analysis.

 

%B ADVANCES IN DISCRETE TOMOGRAPHY AND ITS APPLICATIONS %S Applied and Numerical Harmonic Analysis %I Birkhauser Boston %C Cambridge %P 333 - 366 %8 2007 %@ 978-0-8176-3614-2 %G eng %9 Book chapter %R 10.1007/978-0-8176-4543-4_15 %0 Journal Article %J INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE %D 2007 %T Extraction of an Age-Related Biomarker From Retinal Images Using Appearance Based Approach %A Georg Michelson %A Simone Wärntges %A Rudriger Bock %A László Gábor Nyúl %A Joachim Hornegger %X

Purpose:To develop an appropriate algorithm from retina imagesusing an appearance-based version of the Principal Component Analysis and to test the age-related biomarker’s significance for patients at cardiovascular risk. Methods:Sixty-five men (age, 44.2 ± 11.4 years) and 60 women (age, 48.8 ± 12.6 years) without cardiovascular risk factors and without pathologic eye diagnosis were acquired during a clinical non-experimental cross-sectional survey and represented the control group. Forty-four hypertensive men (age, 45.5 ± 9.4 years; hypertensive for 5.9 ± 6.7 years) and 26 hypertensive women (age, 51.2 ± 7.3 years; hypertensive for 7.9 ± 7.1 years) as well as 57 male smokers (age, 41.8 ± 8.5 years; smoking for 20.6 ± 9.8 years; 15.3 ± 8.6 cigarettes per day) and 60 female smokers (age, 43.2 ± 9.5 years; smoking for 20.1 ± 10.7 years; 13.5 ± 8.1 cigarettes per day) were matched for age and sex to the respective number of control subjects. Results:The reliability of the algorithm was 0.958. The retinal biomarker correlated with age (men, -0.284, p = 0.017; women, -0.374, p = 0.001). Smokers showed a lower biomarker value (male, -0.16 ± 1.29; female, -0.12 ± 0.11) than age-matched control subjects (male, 0.72 ± 0.92, p < 0.001; female, 0.24 ± 0.98, p = 0.048). Hypertension had a similar influence to the biomarker in men (0.10 ± 0.84), but not in women (-0.46 ± 1.23) as compared to age-matched controls (male, 0.57 ± 0.95, p = 0.01; female, 0.06 ± 0.99, p = 0.09). Conclusions:The algorithm of the appearance-based version of the Principal Component Analysis identified an age-related image feature dependent on light intensity with a strong influence to the temporal parapapillary area. It may be used to identify patients at cardiovascular risk.

%B INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE %V 48 %P 2167 %8 2007 %@ 0146-0404 %G eng %N 5 %9 Journal article %! INVEST OPHTH VIS SCI %0 Book Section %B 52nd IWK - Internationales Wissenschaftliches Kolloquium - Volume II. %D 2007 %T Eye Fundus Image Processing System for Automated Glaucoma Classification %A Jörg Meier %A Rudriger Bock %A László Gábor Nyúl %A Georg Michelson %E P Scharff %B 52nd IWK - Internationales Wissenschaftliches Kolloquium - Volume II. %I Technische Universitat %C Ilmenau %P 81 - 84 %8 Sep 2007 %G eng %U http://www.db-thueringen.de/servlets/DerivateServlet/Derivate-12272/IWK_2007_2.pdf %9 Conference paper %0 Thesis %D 2007 %T The 'Gas of Circles' Model and its Application to Tree Crown Extraction %A Peter Horvath %I University of Nice - Sophia Antipolis and University of Szeged %V PhD %8 December 2007 %G eng %9 PhD Thesis %0 Conference Paper %B Proceedings of the European Signal Processing Conference (EUSIPCO) %D 2007 %T A 'gas of Circles' Phase Field Model and its Application to Tree Crown Extraction %A Peter Horvath %A Ian Jermyn %E Marek Domanski %E Ryszard Stasinski %E Maciej Bartkowiak %B Proceedings of the European Signal Processing Conference (EUSIPCO) %C Poznan, Poland %8 2007 %9 Conference paper %0 Book Section %B Image Analysis %D 2007 %T Generation and empirical investigation of hv-Convex discrete sets %A Péter Balázs %E Bjarne Kjær Ersbøll %E Kim Steenstrup Pedersen %X

One of the basic problems in discrete tomography is thereconstruction of discrete sets from few projections. Assuming that the set to be reconstructed fulfils some geometrical properties is a commonly used technique to reduce the number of possibly many different solutions of the same reconstruction problem. Since the reconstruction from two projections in the class of so-called hv-convex sets is NP-hard this class is suitable to test the efficiency of newly developed reconstruction algorithms. However, until now no method was known to generate sets of this class from uniform random distribution and thus only ad hoc comparison of several reconstruction techniques was possible. In this paper we first describe a method to generate some special hv-convex discrete sets from uniform random distribution. Moreover, we show that the developed generation technique can easily be adapted to other classes of discrete sets, even for the whole class of hv- convexes. Several statistics are also presented which are of great importance in the analysis of algorithms for reconstructing hv-convex sets. © Springer-Verlag Berlin Heidelberg 2007.

%B Image Analysis %S Lecture Notes in Computer Science %I Springer Verlag %C Aalborg, Denmark %P 344 - 353 %8 June 2007 %@ 978-3-540-73039-2 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-540-73040-8_35 %0 Thesis %D 2007 %T Markovian Image Models and their Application in Image Segmentation %A Zoltan Kato %8 2007 %G eng %9 PhD Thesis %0 Patent %D 2007 %T Method and system for automatically transforming CT studies to a common reference frame %A Attila Tanacs %A Eörs Máté %A Attila Kuba %7 US Patent Application %8 2007 %G eng %9 Patent %& #20070002046 (Filing Date: 1/04/2007), 2007. %0 Conference Paper %B Proceedings of the Advanced Concepts for Intelligent Vision Systems (ACIVS) %D 2007 %T A Multispectral Data Model for Higher-Order Active Contours and its Application to Tree Crown Extraction %A Peter Horvath %E Wilfried Philips %E Dan Popescu %E Paul Scheunders %B Proceedings of the Advanced Concepts for Intelligent Vision Systems (ACIVS) %C Delft, Netherlands %V 4678 %P 200-211 %8 2007 %9 Conference paper %R 10.1007/978-3-540-74607-2_18 %0 Conference Paper %B Proceedings of the International Conference on Computer Analysis of Images and Patterns (CAIP) %D 2007 %T A New Phase Field Model of a 'gas of Circles' for Tree Crown Extraction from Aerial Images %A Peter Horvath %A Ian Jermyn %E Walter G. Kropatsch %E Martin Kampel %E Allan Hanbury %B Proceedings of the International Conference on Computer Analysis of Images and Patterns (CAIP) %C Vienna, Austria %V 4673 %P 702-709 %8 2007 %9 Conference paper %R 10.1007/978-3-540-74272-2_87 %0 Book Section %B Proccedings of the 5th International Symposium on Image and Signal Processing and Analysis %D 2007 %T Reconstructing some hv-convex binary images from three or four projections %A Péter Balázs %E M Petrou %E T Saramaki %E Aytul Ercil %E Sven Lončarić %X

The reconstruction of binary images from their projections is animportant problem in discrete tomography. The main challenge in this task is that in certain cases the projections do not uniquely determine the binary image. This can yield an extremely large number of (sometimes very different) solutions. Moreover, under certain circumstances the reconstruction becomes NP-hard. A commonly used technique to reduce ambiguity and to avoid intractability is to suppose that the image to be reconstructed arises from a certain class of images having some geometrical properties. This paper studies the reconstruction problem in the class of hv-convex images having their components in so-called decomposable configurations. First, we give a negative result showing that there can be exponentially many images of the above class having the same three projections. Then, we present a heuristic that uses four projections to reconstruct an hv-convex image with decomposable configuration. We also analyze the performance of our heuristic from the viewpoints of accuracy and running time.

%B Proccedings of the 5th International Symposium on Image and Signal Processing and Analysis %I IEEE %C Istanbul, Turkey %P 136 - 140 %8 Sep 2007 %@ 978-953-184-116-0 %G eng %9 Conference paper %R 10.1109/ISPA.2007.4383678 %0 Conference Paper %B BMT 2007: 41. Jahrestagung der Deutschen Gesellschaft für Biomedizinische Technik im VDE %D 2007 %T Retina Image Analysis System for Glaucoma Detection %A Rudriger Bock %A Jörg Meier %A László Gábor Nyúl %A Georg Michelson %A Joachim Hornegger %B BMT 2007: 41. Jahrestagung der Deutschen Gesellschaft für Biomedizinische Technik im VDE %C Aachen, Germany %8 Sep 2007 %G eng %9 Conference paper %0 Book Section %B Pattern Recognition %D 2007 %T A subiteration-based surface-thinning algorithm with a period of three %A Kálmán Palágyi %E Fred A Hamprecht %E Christoph Schnorr %E Bernd Jähne %X

Thinning on binary images is an iterative layer by layer erosionuntil only the "skeletons" of the objects are left. This paper presents an efficient parallel 3D surface-thinning algorithm. A three-subiteration strategy is proposed: the thinning operation is changed from iteration to iteration with a period of three according to the three deletion directions. © Springer-Verlag Berlin Heidelberg 2007.

%B Pattern Recognition %S Lecture Notes on Computer Science %I Springer Verlag %C Heidelberg, Germany %P 294 - 303 %8 Sep 2007 %@ 978-3-540-74933-2 %G eng %9 Conference paper %! LNCS %R 10.1007/978-3-540-74936-3_30 %0 Conference Paper %B International Conference on Computer Assisted Radiology and Surgery (CARS) %D 2007 %T Surgical Planning Tool with Biomechanical Simulation %A Balázs Erdőhelyi %A Endre Varga %A Attila Kuba %X

The fixation of fractured bones often needs a very careful decision making. The operation has to be designed very carefully. A computer assisted system can help the surgeon in the planning phase to increase surgical accuracy. This paper introduces a software tool to plan a surgical intervention and to calculate the biomechanical stability of the plan. The proposed system provides 3D movement and rotation of the bone fragments and the insertion of fixation screws and plates. Finite element analysis is used to calculate mechanical stability of the surgical plan. Using these results the surgeon is able to see the week points of the fixation before the surgery. He can even try several surgical plans to pick the most promising one.

%B International Conference on Computer Assisted Radiology and Surgery (CARS) %I Springer %C Berlin, Germany %V 2 %P S262-S263 %G eng %9 Conference Paper %6 Suppl. 1 %R 10.1007/s11548-007-0098-0 %0 Generic %D 2007 %T A Three-layer MRF model for Object Motion Detection in Airborne Images %A Csaba Benedek %A Tamas Sziranyi %A Zoltan Kato %A Josiane Zerubia %8 2007/// %G eng %0 Book Section %B Bildverarbeitung für die Medizin 2007 %D 2007 %T Whole Body MRI Intensity Standardization %A Florian Jäger %A László Gábor Nyúl %A Bernd Frericks %A Frank Wacker %A Joachim Hornegger %E Alexander Horsch %E Thomas Martin Deserno %E Heinz Handels %E Hans-Peter Meinzer %E Thomas Tolxdorff %X

A major problem of segmentation of magnetic resonance images isthat intensities are not standardized like in computed tomography. This article deals with the correction of inter volume intensity differences that lead to a missing anatomical meaning of the observed gray values. We present a method for MRI intensity standardization of whole body MRI scans. The approach is based on the alignment of a learned reference and the current histogram. Each of these histograms is at least 2-d and represents two or more MRI sequences (e.g., T1- and T2-weighted images). From the matching a non-linear correction function is gained which describes a mapping between the intensity spaces and consequently adapts the image statistics to a known standard. As the proposed intensity standardization is based on the statistics of the data sets only, it is independent from spatial coherences or prior segmentations of the reference and newly acquired images. Furthermore, it is not designed for a particular application, body region or acquisition protocol. The method was evaluated on whole body MRI scans containing data sets acquired by T1/FL2D and T2/TIRM sequences. In order to demonstrate the applicability, examples from noisy and pathological image series acquired on a whole body MRI scanner are given.

%B Bildverarbeitung für die Medizin 2007 %S Informatik aktuell %I Springer-Verlag %C München, Germany %P 459 - 463 %8 March 2007 %@ 978-3-540-71090-5 %G eng %9 Conference paper %R 10.1007/978-3-540-71091-2_92 %0 Conference Paper %B Proceedings of the International Conference on Pattern Recognition (ICPR) %D 2006 %T A Higher-Order Active Contour Model for Tree Detection %A Peter Horvath %A Ian Jermyn %A Zoltan Kato %A Josiane Zerubia %X

We present a model of a 'gas of circles', the ensemble of regions in the image domain consisting of an unknown number of circles with approximately fixed radius and short range repulsive interactions, and apply it to the extraction of tree crowns from aerial images. The method uses the recently introduced 'higher order active contours' (HOACs), which incorporate long-range interactions between contour points, and thereby include prior geometric information without using a template shape. This makes them ideal when looking for multiple instances of an entity in an image. We study an existing HOAC model for networks, and show via a stability calculation that circles stable to perturbations are possible for constrained parameter sets. Combining this prior energy with a data term, we show results on aerial imagery that demonstrate the effectiveness of the method and the need for prior geometric knowledge. The model has many other potential applications.

%B Proceedings of the International Conference on Pattern Recognition (ICPR) %I IAPR %C Hong Kong, China %V 2 %P 130–133 %8 2006 %9 Conference paper %0 Journal Article %J Acta Cybernetica %D 2006 %T Image reconstruction and correction methods in neutron and X-ray tomography %A Zoltán Kiss %A Lajos Rodek %A Attila Kuba %X

Neutron and X-ray tomography are imaging techniques for getting information about the interior of objects in a non-destructive way. They reconstruct cross-sections from projection images of the object being investigated. Due to the properties of the image acquisition system, the projection images are distorted by several artifacts, and these reduce the quality of the reconstruction. In order to eliminate these harmful effects the projection images should be corrected before reconstruction. Taking projections is usually an expensive and time consuming procedure. One of our main goals has been to try to minimize the number of projections - for example, by exploiting more a priori information. A possible way of reducing the number of projections is by the application of discrete tomographic methods. In this case a special class of objects can be reconstructed, consisting of only a few homogenous materials that can be characterized by known discrete absorption values. To this end we have implemented two reconstruction methods. One is able to reconstruct objects consisting of cylinders and spheres made of homogeneous materials only. The other method is a general one in the sense that it can be used for reconstructing any shape. Simulations on phantoms and physical measurements were carried out and the results are presented here.

%B Acta Cybernetica %I University of Szeged %C Szeged, Hungary %V 17 %P 557-587 %G eng %9 Journal Article %0 Conference Paper %B Workshop on Discrete Tomography and its Applications (WDTA) %D 2005 %T Multi-resolution method for binary tomography %A László Ruskó %A Attila Kuba %X

Multi-resolution and region-growing strategies have been successfully used in several fields of image processing. In this paper we investigate how these two strategies can be applied for binary tomography. We included these strategies into a reconstruction method using simulated annealing and tested these new methods on different images.

%B Workshop on Discrete Tomography and its Applications (WDTA) %C New York City, USA %V Proceedings of the Workshop on Discrete Tomography and its Applications (WDTA) %P 299-311 %8 2005 %G eng %9 Conference paper %6 20 %R 10.1016/j.endm.2005.05.070 %0 Journal Article %J IEEE Transactions on Nuclear Science %D 2005 %T Preliminary studies of discrete tomography in neutron imaging %A Atila Kuba %A László Ruskó %A Lajos Rodek %A Zoltán Kiss %X

Discrete tomography (DT) is a new technique to reconstruct discrete images from their projections (like neutron images). The reconstruction methods in DT are different from the conventional ones, because the created images may contain only a few numbers of given discrete values. One of the main reasons to apply DT is that hopefully we need only a few numbers of projections. In many applications we have a situation where we know the material components of the object to be studied, that is, we know the discrete values of the image to be reconstructed. Using discreteness and some a priori information we can apply several DT methods in neutron imaging. Most of the DT reconstruction methods are reducing the problem to an optimization task. We tried two such methods on software and physical phantoms. In these experiments we investigated the effects of the following parameters: number of projections, noise levels, and complexity of the object to be reconstructed. We also developed a software system, called DIRECT, for testing different DT methods, to compare them and to present the reconstructed objects.

%B IEEE Transactions on Nuclear Science %I IEEE %V 52 %P 380-385 %8 2005 %G eng %9 Journal Article %R 10.1109/TNS.2005.843657 %0 Conference Proceedings %B Workshop on Discrete Tomography and its Applications %D 2005 %T Proceedings of the Workshop on Discrete Tomography and its Applications %A Gábor T. Herman %A Attila Kuba %B Workshop on Discrete Tomography and its Applications %I Elsevier %V Electronic Notes in Discrete Mathematics %8 July 2005 %G eng %9 Proceedings %6 20 %0 Journal Article %J Theoretical Computer Science %D 2005 %T A sufficient condition for non-uniqueness in binary tomography with absorption %A Attila Kuba %A Maurice Nivat %X

A new kind of discrete tomography problem is introduced: the reconstruction of discrete sets from their absorbed projections. A special case of this problem is discussed, namely, the uniqueness of the binary matrices with respect to their absorbed row and column sums when the absorption coefficient is n=log((1+5^0.5)/2). It is proved that if a binary matrix contains a special structure of 0s and 1s, called alternatively corner-connected component, then this binary matrix is non-unique with respect to its absorbed row and column sums. Since it has been proved in another paper [A. Kuba, M. Nivat, Reconstruction of discrete sets with absorption, Linear Algebra Appl. 339 (2001) 171–194] that this condition is also necessary, the existence of alternatively corner-connected component in a binary matrix gives a characterization of the non-uniqueness in this case of absorbed projections.

%B Theoretical Computer Science %V 346 %P 335-357 %8 2005 %G eng %9 Journal Article %R 10.1016/j.tcs.2005.08.024 %0 Journal Article %J Alkamazott Matematikai Lapok %D 2004 %T Image registration methods based on interactively identified point pairs %A Attila Tanacs %B Alkamazott Matematikai Lapok %V 21 %P 237-260 %8 2004 %G eng %9 Journal Article %0 Journal Article %J Der Radiologe %D 2003 %T 3D-Querschnittsprofil des Laryngotrachealtrakts—Eine neue Methode zur Visualisierung und Quantifizierung von Trachealstenosen %A Sorantin, Erich. %A Halmai, Csongor. %A Balázs Erdőhelyi %A Kálmán Palágyi %A László Gábor Nyúl %A Ollé, Krisztián. %A Geiger, B. %A Lindbichler, F. %A Friedrich, G. %A Kiesler, K. %X

Purpose

Demonstration of a technique for 3D assessment of tracheal stenoses, regarding site, length and degree, based on spiral computed tomography (S-CT).

Patients and Methods

S-CT scanning and automated segmentation of the laryngo-tracheal tract (LTT) was followed by the extraction of the LTT medial axis using a skeletonisation algorithm. Orthogonal to the medial axis the LTT 3D cross sectional profile was computed and presented as line charts, where degree and length were obtained. Values for both parameters were compared between 36 patients and 18 normal controls separately. Accuracy and precision was derived from 17 phantom studies.

Results

Average degree and length of tracheal stenoses were found to be 60.5% and 4.32 cm in patients compared to minor caliber changes of 8.8% and 2.31 cm in normal controls (p <0.005). For the phantoms an excellent correlation between the true and computed 3D cross sectional profile was found (p <0.005) and an accuray for length and degree measurements of 2.14 mm and 2.53% respectively could be determined. The corresponding figures for the precision were found to be 0.92 mm and 2.56%.

Conclusion

LTT 3D cross sectional profiles permit objective, accurate and precise assessment of LTT caliber changes. Minor LTT caliber changes can be observed even in normals and, in case of an otherwise normal S-CT study, can be regarded as artefacts.

 

%B Der Radiologe %I Springer-Verlag %V 43 %P 1056-1068 %8 2003 %G eng %U http://dx.doi.org/10.1007/s00117-003-0990-8 %9 Journal Article %R 10.1007/s00117-003-0990-8 %0 Journal Article %J Proceedings of the IEEE %D 2003 %T Discrete tomography in medical imaging %A Gábor T. Herman %A Attila Kuba %B Proceedings of the IEEE %V 91 %P 1612-1626 %8 October %G eng %R 10.1109/JPROC.2003.817871 %0 Conference Paper %B 7th World Conference on Neutron Radiography (WCNR) %D 2002 %T Composition of Radiography Pictures of Whole Helicopter Rotor Blades in Hungary %A Márton Balaskó %A Zoltán Balaskó %A Emese Balogh %A Attila Tanacs %A Endre Katona %A Attila Kuba %B 7th World Conference on Neutron Radiography (WCNR) %P 637-642 %8 2002 %G eng %9 Conference paper %0 Journal Article %J IEEE Transactions on Medical Imaging %D 2002 %T Mathematical generation of normal data for evaluating myocardial perfusion studies %A Marianna Dudásné-Nagy %A Eörs Máté %A Béla Kári %B IEEE Transactions on Medical Imaging %V 21 %P 1358- 1365 %G eng %R 10.1109/TMI.2002.806429 %0 Journal Article %J Theoretical Computer Science %D 2002 %T Reconstruction of convex 2D discrete sets in polynomial time %A Attila Kuba %A Emese Balogh %X

The reconstruction problem is considered in those classes of discrete sets where the reconstruction can be performed from two projections in polynomial time. The reconstruction algorithms and complexity results are summarized in the case of hv-convex sets, hv-convex 8-connected sets, hv-convex polyominoes, and directed h-convex sets. As new results some properties of the feet and spines of the hv-convex 8-connected sets are proven and it is shown that the spine of such a set can be determined from the projections in linear time. Two algorithms are given to reconstruct hv-convex 8-connected sets. Finally, it is shown that the directed h-convex sets are uniquely reconstructible with respect to their row and column sum vectors.

%B Theoretical Computer Science %V 283 %P 223-242 %8 June %G eng %R 10.1016/S0304-3975(01)00080-9 %0 Journal Article %J Acta Cybernetica %D 2001 %T A 3D parallel shrinking algorithm %A Kálmán Palágyi %X

Shrinking is a frequently used preprocessing step in image processing. This paper presents an efficient 3D parallel shrinking algorithm for transforming a binary object into its topological kernel. The applied strategy is called directional: each iteration step is composed of six subiterations each of which can be executed in parallel. The algorithm makes easy implementation possible, since deletable points are given by 3x3x3 matching templates. The topological correctness of the algorithm is proved for (26,6) binary pictures.

%B Acta Cybernetica %I University of Szeged %C Szeged %V 15 %P 201-211 %G eng %9 Journal Article %0 Journal Article %J Linear Algebra and its Applications %D 2001 %T Comparison of algorithms for reconstructing hv-convex discrete sets %A Emese Balogh %A Attila Kuba %A Csaba Devenyi %A Alberto Del Lungo %B Linear Algebra and its Applications %V 339 %P 23-35 %8 December %G eng %R 10.1016/S0024-3795(01)00430-X %0 Journal Article %J Linear Algebra and its Applications %D 2001 %T Reconstruction of 4- and 8-connected convex discrete sets from row and column projections %A Sara Brunetti %A Alberto DelLungo %A F. DelRistoro %A Attila Kuba %A Maurice Nivat %X

In this paper we examine the problem of reconstructing a discrete two-dimensional set from its two orthogonal projection (H,V) when the set satisfies some convexity conditions. We show that the algorithm of the paper [Int. J. Imaging Systems and Technol. 9 (1998) 69] is a good heuristic algorithm but it does not solve the problem for all (H,V) instances. We propose a modification of this algorithm solving the problem for all (H,V) instances, by starting to build the ``spine''. The complexity of our reconstruction algorithm is O(mnˇlog(mn)ˇmin{m2,n2}) in the worst case. However, according to our experimental results, in 99% of the studied cases the algorithm is able to reconstruct a solution without using the newly introduced operation. In such cases the upper bound of the complexity of the algorithm is O(mnˇlog(mn)). A systematic comparison of this algorithm was done and the results show that this algorithm has the better average complexity than other published algorithms. The way of comparison and the results are given in a separate paper [Linear Algebra Appl. (submitted)]. Finally we prove that the problem can be solved in polynomial time also in a class of discrete sets which is larger than the class of convex polyominoes, namely, in the class of 8-connected convex sets.

%B Linear Algebra and its Applications %V 339 %P 37-57 %G eng %R 10.1016/S0024-3795(01)00435-9 %0 Journal Article %J Linear Algebra and its Applications %D 2001 %T Reconstruction of discrete sets with absorption %A Attila Kuba %A Maurice Nivat %X

The uniqueness problem is considered when binary matrices are to be reconstructed from their absorbed row and column sums. Let the absorption coefficient n be selected such that en = (1+5^0.5)/2. Then it is proved that if a binary matrix is non-uniquely determined, then it contains a special pattern of 0s and 1s called composition of alternatively corner-connected components. In a previous paper [Discrete Appl. Math. (submitted)] we proved that this condition is also sufficient, i.e., the existence of such a pattern in the binary matrix is necessary and sufficient for its non-uniqueness.

%B Linear Algebra and its Applications %V 339 %P 171-194 %G eng %U http://www.sciencedirect.com/science/article/B6V0R-44CHW26-C/2/e4cd2b3dc91dbb828db15e331a6230cc %R 10.1016/S0024-3795(01)00486-4 %0 Report %D 1999 %T Bayesian Color Image Segmentation Using Reversible Jump Markov Chain Monte Carlo %A Zoltan Kato %I ERCIM/CWI %C Amsterdam, The Netherlands %8 January 1999 %G eng %9 Research Report %0 Book %B Applied and Numerical Harmonic Analysis %D 1999 %T Discrete Tomography: Foundations, Algorithms, and Applications %A Gábor T. Herman %A Attila Kuba %B Applied and Numerical Harmonic Analysis %I Birkhauser %8 December 1999 %G eng %9 Book %0 Conference Paper %B International Conference on Image Analysis and Processing (ICIAP'99) %D 1999 %T An Interpretation System for Cadastral Maps %A Endre Katona %A György Hudra %B International Conference on Image Analysis and Processing (ICIAP'99) %I IEEE %P 792-797 %8 1999 %G eng %9 Conference paper %0 Generic %D 1993 %T Assessment of myocardial function with gated SPECT before and after coronary by-pass surgery %A János Mester %A István Kósa %A Eörs Máté %A Vera Matievics %A G Lupkovics %A Gábor Kovács %A László Csernay %B European Journal of Nuclear Medicine %V 10 %P 918 %8 1993 %9 Abstract %0 Generic %D 1993 %T Efficiency of the orthopan tomoscintigram (OPTS) in abnormalities of the jaws %A Mária Rajtár %A Eörs Máté %A András Fazekas %A György Szabó %A László Csernay %B European Journal of Nuclear Medicine %V 10 %P 898 %8 1993 %G eng %9 Abstract %0 Generic %D 1993 %T Investigation of left ventricular wall motion by gated blood-pool SPECT, using three-dimensional display of Fourier phase and amplitude %A János Mester %A István Kósa %A Vera Matievics %A Eörs Máté %A László Csernay %B First International Congress of Nuclear Cardiology, Abstract book %0 Journal Article %J Journal of Nuclear Medicine %D 1992 %T Can Dynamic Krypton-81m Imaging Separate Regional Ventillation and Volume? %A MF Lythgoe %A H Deavies %A Attila Kuba %A Mihály Tóth-Abonyi %B Journal of Nuclear Medicine %V 33 %P 1935-1939 %8 1992 %G eng %9 Journal Article %0 Journal Article %J International Journal of Imaging Systems and Technology %D 1992 %T Data processing system for nuclear medicine images %A Attila Kuba %A Árpád Makay %A Eörs Máté %A László Csernay %B International Journal of Imaging Systems and Technology %V 4 %P 51-61 %G eng %R 10.1002/ima.1850040111 %0 Journal Article %J International Journal of Imaging Systems and Technology %D 1992 %T Data processing system for nuclear medicine images %A Attila Kuba %A Árpád Makay %A Eörs Máté %A László Csernay %B International Journal of Imaging Systems and Technology %V 4 %P 51-61 %8 1992 %G eng %9 Journal Article %0 Generic %D 1992 %T Documentation of changes in regional myocardial function due to coronary bypass surgery by gated SPECT, using three-dimensional display of Fourier phase and amplitude %A János Mester %A Isván Kósa %A Eörs Máté %A G Lupkovics %A Gábor Kovács %A László Csernay %B European Heart Journal %V 13 %P 360 %8 1992 %G eng %9 Abstract %0 Journal Article %J Journal on Nuclear Medicine %D 1992 %T Three-dimensional presentation of the Fourier amplitude and phase: A fast display method for gated cardiac blood-pool SPECT %A Eörs Máté %A János Mester %A László Csernay %A Attila Kuba %A S Madani %A Árpád Makay %B Journal on Nuclear Medicine %V 33 %P 458-462 %8 1992 %G eng %9 Journal Article %0 Generic %D 1991 %T 3D presentation of the Fourier amplitude and phase. A new fast display method for gated cardiac blood pool SPECT %A János Mester %A Eörs Máté %A László Csernay %A Attila Kuba %A S Madani %A Árpád Makay %B European Jounal of Nuclear Medicine %V 18 %P 693 %8 1991 %G eng %9 Abstract %0 Journal Article %J Nuclear Medicine Communications %D 1986 %T Detection and localisation of ventricular preexcitation in Wolff-Parkinson-White syndrome (comparative study with body surface mapping) %A János Mester %A I Preda %A G Kozmann %A Eörs Máté %A L Regos %A K Tóth %A György Marosi %A Zoltán Antalóczy %A László Csernay %B Nuclear Medicine Communications %V 7 %P 497-504 %8 July %G eng %0 Journal Article %J Acta Cybernetica %D 1986 %T The probabilistic behaviour of the NFD bin packing algorithm %A János Csirik %A Eörs Máté %B Acta Cybernetica %V 7 %P 241-245 %G eng