An artificial retina chip made of a 128 x 128 pn-np variable-sensitivity photodetector array

An artificial retina chip is an image detection device that, like biological retinas, can extract essential features directly from projected images. This paper presents an artificial retina chip consisting of a 128/spl times/128 array of pn-np variable-sensitivity photodetectors (VSPD's). This photodetector (PD) utilizes pn junctions and thus avoids the rather inflexible memory effect encountered in our previously reported device, which used Schottky contacts in a metal-semiconductor-metal (MSM) configuration. We introduce a novel "filter division" method for arbitrary two-dimensional (2-D) filter operation, and successfully employ it in a 2-D edge extraction task.<
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