US Patent 7819525 Automatic direct gaze detection based on pupil symmetry

The present invention provides a system and methods for direct gaze detection based on pupil symmetry. The system and methods work by first finding the user's eyes in a video camera image and measuring the symmetry of the pupil region. If this pupil region is close to round, the invention determines that the user is looking nearly directly or close to directly at the camera, or has direct gaze at the camera. This technique handles both eye motions and head motions (e.g., the gaze may shift with or without the head being turned).