Improvement of Robustness in Pupil Detection Assuming a Constant Interpupillary Distance in a Video-Based Eye-Gaze Detection System

—A Solution of Glasses Reflection Problem—

Abstract

In the pupil-corneal reflection detection-based eye-gaze detection method, glasses reflection of near-infrared LED light sources for producing the corneal reflection is misdetected as the pupil when a user wears eyeglasses. To improve the robustness of the pupil detection, we propose novel pupil searching and tracking methods using two stereo-calibrated cameras and light sources. The pupil searching method detects the true pair of the right and left pupils under the constraints of the suitable 3-D interpupillary distance and 3-D position of the pair, which are given in advance. Even if one pupil is not detected in the image of either camera owing to the glasses reflections, the pupil tracking method estimates the 3-D coordinates of the undetected pupil by using the constant interpupillary distance and the temporal continuity of the 3-D coordinates of the moving pupil. The experimental results show that the accuracy of pupil searching and tracking was better than that of the conventional one-camera method.