3D gaze tracking with easy calibration using stereo cameras for robot and human communication

This paper presents a method to estimate the optic and visual axes of an eye and the Point Of Gaze (POG) on the bases of Listing’s law using stereo cameras for three-dimensional (3D) gaze tracking. By using two cameras and two light sources, the optic axis of the eye can be estimated on the basis of a spherical model of a cornea. A one-point calibration is required to estimate the angle of the visual axis from the optic axis. However, a real cornea has an aspheric shape and therefore it is difficult to estimate the POG in all the directions accurately. We have used three light sources to improve the estimation of the POG. Two light sources near the center of the pupil in the camera image are used for estimating the POG. The experimental results show that the accuracy of the estimation of the visual axis is under about 1°.