Feature tracking linear optic flow sensor chip

This paper presents a VLSI-friendly linear optic flow sensor capable of being implemented on a single chip. This sensor belongs to the “token method” class of optic flow sensors: motion is measured by tracing the movement of a “token” or a feature across the focal plane. Specially shaped photoreceptor circuits and simple analog circuitry implement an array of feature detectors on the focal plane chip. The determination of a feature´s location in the focal plane is performed using a winner-take-all (WTA) circuit. Motion is detected by using compact logic circuitry to detect appropriate movements of the high WTA output. Speed measurement is performed by timing how long an edge stays at one location before moving to the next