
313Automatization of Dry Eye Syndrome Tests
The eye can move through the sequence, so it is necessary to register it in each frame.
Thus, the methodology is independent of slight motions of the ROI since the iris appears
in the same location in the aligned video. To this end, the circles representing the iris are
aligned from the center of the ROI detected in the consecutive frames. Moreover, a second
alignment is performed based on minimizing differences of intensities in an area sur-
rounding the iris. In order to avoid cumulative error, the sequence is treated as a set of
blocks composed of a few consecutive images. The rst image of each bl ...