| abstract |
The invention is an apparatus for measuring eye gaze and fixation duration employing an electronic video display array as sequential sources of eye illumination. The video display of the apparatus may be task related or near infrared light sources used merely to track the user's eye. The apparatus of the invention is based on an opto-transistor array, a comparator array and an encoder and latch clocked by the raster-scan pulses of the display driver, which are configured to construct a pairing table of sequential source corneal reflections to sensor activations over the display field refresh cycle. An accurate three dimensional ocular model is computed from opthalmometric techiniques from which the viewing direction and fixation duration are derived. The apparatus is easily extended to the simultaneous tracking of both eyes and is designed to be used with head-mounted video displays. The accuracy of the apparatus is independent of shifts of the helmet on the user's head. Additionally, the apparatus is readily incorporated into panel mounted displays and head-free sensor arrays. The apparatus can be used as an eyetracker to control computerized machinery by ocular gaze point of regard and fixation duration. |