Retinomorphic vision systems

The new generation of silicon retinae has two defining characteristics. First, these synthetic retinae are morphologically equivalent to their biological counterparts-at an appropriate level of abstraction. Second, they accomplish all four major operations performed by biological retinae using neurobiological principles: (1) continuous sensing for detection, (2) local automatic gain control for amplification, (3) spatiotemporal bandpass filtering for preprocessing, and (4) adaptive sampling for quantization. The author introduces the term retinomorphic to refer to this subclass of the neuromorphic electronic systems. Their design principles are compared and contrasted with the standard practice in imager design. It is argued that neurobiological principles are best suited to perceptive systems that go beyond reproducing the dynamic scene, like a conventional video camera does, to extracting salient information in real time. The results from a fully operational retinomorphic vision system are presented and the trade-offs involved in its design are discussed.