“…Methods for detecting the eyes include the use of gradient flow fields [37], color-based techniques for detection of the eye sclera [5], horizontal gradient maps of a skin-colored region [48,51], and pupil detection using infrared or other special lighting [2,31,40,54]. References [1,7,13,17,18,21,38,40,50] explain various face and head tracking techniques previously employed. Temporal differencing is often used to segment moving regions of interest from a stable background [15,16].…”