Abstract

We present a robust, frame-rate pupil detector technique, based on an active illumination scheme, used for gaze estimation. The pupil detector uses two light sources synchronized with the even and odd fields of the video signal (interlaced frames), to create bright and dark pupil images. The retro-reflectivity property of the eye is exploited by placing an infra-red (IR) light source close to the camera's optical axis resulting in an image with a bright pupil. A similar off axis IR source generates an image with dark pupils. Pupils are detected from the thresholded difference of the bright and dark pupil images. After a calibration procedure, the vector computed from the pupil center to the center of the corneal glints generated from light sources is used to estimate the gaze position. The frame-rate gaze estimator prototype is currently being demonstrated in a docked 300 MHz IBM Thinkpad with a PCI frame grabber, using interlaced frames of resolution 640$\times$480$\times$8 bits.