Time-derivative adaptive silicon photoreceptor array

Abstract

We designed and tested a two-dimensional silicon receptor array constructed from pixels that temporally high-pass filter the incident image. There are no surround interactions in the array; all pixels operate independently except for their correlation due to the input image. The high- pass output signal is computed by sampling the output of an adaptive, high-gain, logarithmic photoreceptor during the scanout of the array. After a pixel is sampled, the output of the pixel is reset to a fixed value. An interesting capacitive coupling mechanism results in a controllable high-pass filtering operation. The resulting array has very low offsets. The computation that the array performs may be useful for time-domain image processing, for example, motion computation.