Temporal photoreception for adaptive dynamic range image sensing and encoding

Neural Netw. 1998 Oct;11(7-8):1149-1158. doi: 10.1016/s0893-6080(98)00070-7.

Abstract

We have implemented two analog VLSI computational sensors for sensing and encoding high dynamic range images by exploiting temporal dimension of photoreception. The first sensor is a multi-integration time photoreceptor that automatically adapts to use different integration periods depending on light intensity. It exhibits a dynamic range 128 times larger than that of a single integration period photoreceptor, approximately 1:128000. The second sensor is an intensity-to-time processing paradigm that is based on the notion that stronger stimuli elicit responses before weaker ones. The paradigm sorts pixels of sensed images by their intensities, thus achieving information-theoretic optimal encoding of images. It handles dynamic range of approximately 1:1000000. Both implementations can operate at standard video rate of 30framess(-1).