PPT Slide
Problems occurred in field tests performed under real conditions (1)
- Face size and position. In practice, it is very difficult to control the position of the subject with respect to the camera.
- Changes in illumination. If a spotlight is not used, lighting variations occur. For example, close to a window, the lighting depends strongly on the day-time and the weather.
- Facial expressions. In practice, it is almost impossible to control the mood of the subject. The smile causes probably the largest variation of facial expressions.