User-calibration-free gaze estimation method using a binocular 3D eye model

Abstract

This paper presents a user-calibration-free method for estimating the point of gaze (POG). This method provides a fast and stable solution for realizing user-calibration-free gaze estimation more accurately than the conventional method that uses the optical axis of the eye as an approximation of the visual axis of the eye. The optical axis of the eye can be estimated by using two cameras and two light sources. This estimation is carried out by using a spherical model of the cornea. The point of intersection of the optical axis of the eye with the object that the user gazes at is termed POA. On the basis of an assumption that the visual axes of both eyes intersect on the object, the POG is approximately estimated using the binocular 3D eye model as the midpoint of the line joining the POAs of both eyes. Based on this method, we have developed a prototype system that comprises a 19′ display with two pairs of stereo cameras. We evaluated the system experimentally with 20 subjects who were at a distance of 600mm from the display. The root-mean-square error (RMSE) of measurement of POG in the display screen coordinate system is 1.58°. © 2011 The Institute of Electronics, Information and Communication Engineers.