Gaze Estimation From Color Image Based on the Eye Model With Known Head Pose

This paper proposes a novel method of gaze estimation based on an eye model with known head pose. The most crucial factors in the eye-model-based approach to gaze estimation are the 3-D positions of the eyeball and iris centers. In the proposed method, an RGB-D camera, Kinect sensor, is used to obtain the head pose as well as the eye region of the color image. The 3-D position of the eyeball center is determined in the calibration phase by gazing at the center of the color image camera. Then, to estimate the 3-D position of the iris center, the 3-D contour of the iris is projected onto the color image with the known head pose obtained from color and depth cues of an RGB-D camera. Thus, the ellipse of the iris in the image can be described using only two parameters: the yaw and pitch angles of the eyeball in the iris co-ordinate system, rather than the conventional five parameters of an ellipse. The proposed method can fit an iris that is not complete due to eyelid occlusion. The average errors of vertical and horizontal angles of the gaze estimation for seven subjects are 5.9 degrees and 4.4 degrees, respectively. The processing speed is as high as 330 ms per frame. However, for lower resolution and poor illumination images, as tested on the public database EYEDIAP, the performance of the proposed eye-model-based method is inferior to that of the-state-of-the-art appearance-based method.