US Patent 9398848 Eye gaze tracking

A method of performing eye gaze tracking of at least one eye of a user, by determining the position of the center of the eye, said method comprising the steps of:detecting the position of at least three reflections on said eye,transforming said positions to spanning a normalized coordinate system spanning a frame of reference,detecting the position of said center of the eye relative to the position of said reflections and transforming this position to said normalized coordinate system,tracking the eye gaze by tracking the movement of said eye in said normalized coordinate system.