  In this paper, we clarify how to recognize different levels of vigilance for
vehicle drivers. In order to avoid the classical problems of crisp logic, we
preferred to employ a fuzzy logic-based system that depends on two variables to
make the final decision. Two iris segmentation techniques are well illustrated.
A new technique for pupil position detection is also provided here with the
possibility to correct the pupil detected position when dealing with some noisy
cases.
