Direct image processing using arrays of variable-sensitivity photodetectors

This paper describes an image sensor with direct processing capability that is based on an array of variable-sensitivity photodetectors (VSPDs). Despite its simple structure, it is still able to perform a variety of fast processing operations on images. Its flexibility differentiates it from devices that provide only a single processing function, and its use of optoelectronic devices for processing differentiates it from devices that perform all processing electronically. The viability of this approach has already been confirmed using devices with 20/spl times/20 and 64/spl times/64 metal-semiconductor-metal (MSM) VSPDs on a semi-insulating GaAs substrate. Here, the results are given using a device with 128/spl times/128 VSPDs that employ pn-np structures instead of Schottky contacts.