Calibration-free gaze tracking using a binocular 3D eye model

This paper presents a calibration-free method for estimating the point of gaze (POG) on a display by using two pairs of stereo cameras. By using one pair of cameras and two light sources, the optical axis of the eye and the position of the center of the cornea can be estimated. This estimation is carried out by using a spherical model of the cornea. One pair of cameras is used for the estimation of the optical axis of the left eye, and the other pair is used for the estimation of the optical axis of the right eye. The point of intersection of optical axis with the display is termed the point of the optical axis (POA). The POG is approximately estimated as the midpoint of the line joining POAs of both the eyes with the display. We have developed a prototype system based on this method and demonstrated that the midpoint of POAs was closer to the fiducial point that the user gazed at than each POA.