In order to extract the high-precision sub-pixel feature parameters,this paper presents a high-precision sub-pixel feature extraction method based on the multichannel image by use of the phenomenon of the bright pupil. Firstly
the pupil area is obtained by filter on a difference image. Then the edge of the pupil area is detected and cornea reflection area is searched nearby the eye area based on gray level. Then corneal reflex center is located by centroid and the edge of the pupil is filtered to eliminate the impact of corneal reflex to the contour of the pupil. Ellipse fitting is used to locate the pupil center. Finally
multiple parameters of facial features and face position are extracted.We establish a multi-feature extraction process
which provides parameter basis for gaze estimation which is in the next step. The results of feature extraction and the ultimate gaze estimation results made by gaze tracking system verify the effectiveness of the method.