An Algorithm for Real-Time Eye-Movement Tracking with Free Head Movement

A fast algorithm for real-time eye-movement tracking with free head movement based using image subtraction was proposed in this study. for this purpose four reference points consisted of infra-red LEDs were used to compensate the subject´s head movement and a fast gazing point detection algorithm was developed and applied to determine the subject´s gazing point by comparing the relative distance and angle between the center points of the pupil area. the size of input image was scaled down to 1/16 to detect the eye and its neighbor area quickly and the theorem for a circumcenter of a triangle was applied to detect the center of the pupil