A Real-Time Gaze Position Estimation Method Based on a 3-D Eye Model

This paper proposes a new gaze-detection method based on a 3-D eye position and the gaze vector of the human eyeball. Seven new developments compared to previous works are presented. First, a method of using three camera systems, i.e., one wide-view camera and two narrow-view cameras, is proposed. The narrow-view cameras use autozooming, focusing, panning, and tilting procedures (based on the detected 3-D eye feature position) for gaze detection. This allows for natural head and eye movement by users. Second, in previous conventional gaze-detection research, one or multiple illuminators were used. These studies did not consider specular reflection (SR) problems, which were caused by the illuminators when working with users who wore glasses. To solve this problem, a method based on dual illuminators is proposed in this paper. Third, the proposed method does not require user-dependent calibration, so all procedures for detecting gaze position operate automatically without human intervention. Fourth, the intrinsic characteristics of the human eye, such as the disparity between the pupillary and the visual axes in order to obtain accurate gaze positions, are considered. Fifth, all the coordinates obtained by the left and right narrow-view cameras, as well as the wide-view camera coordinates and the monitor coordinates, are unified. This simplifies the complex 3-D converting calculation and allows for calculation of the 3-D feature position and gaze position on the monitor. Sixth, to upgrade eye-detection performance when using a wide-view camera, the adaptive-selection method is used. This involves an IR-LED on/off scheme, an AdaBoost classifier, and a principle component analysis method based on the number of SR elements. Finally, the proposed method uses an eigenvector matrix (instead of simply averaging six gaze vectors) in order to obtain a more accurate final gaze vector that can compensate for noise. Experimental results show that the root mean square error of gaze detection was about 0.627 cm on a 19-in monitor. The processing speed of the proposed method (used to obtain the gaze position on the monitor) was 32 ms (using a Pentium IV 1.8-GHz PC). It was possible to detect the user's gaze position at real-time speed