PPT Slide
Considering empirical (visual, clinical) analysis of image sequence and omitting the abstract terms, the 2 steps can be interpreted as:
- select the most dissimilar images of a sequence (they are expected to display 1 dominant factor and being close to the true factor image but still contain structures of more than 1 factor), and
- subtract between them to remove residuals of other factors and display a single factor structure per image.