A three sensor eye tracking system based on electrooculography

A three sensor electrooculography (EOG) system based on the Electric Potential Sensor (EPS) is presented, covering the advantages it offers in eye tracking over conventional biopotential electrode systems which typically employ five electrodes for this type of full eye tracking. The sensors have been mounted to an easy to put on headband and the use of three sensors eliminates the need for additional facial electrodes. The EPS is based on an active electrode with an ultra high input impedance of ∼50GΩ and ∼7pF. The sensors capacitively couple to the skin through an inert insulating layer, thus no skin preparation or conductive gels are required. There is no DC drift and the EPS does not suffer any negative effects due to variations in skin resistance caused by sweating. A typical EOG signal is shown with no visible crosstalk. Experimental results are presented for a variety of subjects, where horizontal and vertical EOG measurements with respect to eye gaze position.