Wrong results obtained for the compared methods 1 and 2. Method 1 (first column) does not work well when the parameters of the active contour are chosen incorrectly or the points are wrongly indicated by an operator. Method 2 (second column) cannot cope in the event of improper illumination of the eye. In these cases, it incorrectly identifies the pupil contour during binarization. The interesting fragments are marked with white arrows and areas.