US Patent 10321055 Low power eye tracking system and method

A method of reducing the illumination power requirements for an object tracking system, the method including the steps of: (a) determining a current location of the object within a scene; (b) for a future frame: determining a band around the object of interest; determining a start and stop time for when the rolling shutter detector will be sampling the band; and illuminating the object only while the rolling shutter detector is sampling the band; (c) for a future frame predicting the location of the object relative to the tracking system; determining the ambient light levels; and illuminating the object with the minimum optical power required for the object to be imaged suitably for tracking.