Pupil detection and tracking for analysis of fixational eye micromovements

Even with fixed gaze, the human eye is under steady motion (tremor micosaccades and drifts). Detection of these movements requires of invasive techniques or expensive devices with sophisticated detection methods. In this paper we present a technique for pupil segmentation and contour analysis which will provide valuable information about fixational eye movements. The method is based on fitting an ellipse to the pupil contour. Pupillary hippus, microsaccades and drifts are obtained as well as cyclotorsional movements. The method is simple and the experimental requirements are easily available since just a biomicroscope and a digital videocamera are required.