In this paper, we propose a novel image sensor by which the image signal can be compressed. Since the image signal is compressed on the imager plane by making use of the parallel nature of image signals, the amount of signal readout from the imager can be significantly reduced. Thus, the proposed sensor can potentially be applied to high-pixel-rate cameras and real-time processing systems which require very high-speed imaging and very high resolution for real-time imaging; the very high bandwidth is the fundamental limitation to the feasibility of such high-pixel-rate sensors and processing systems. The proposed sensor utilizes a conditional replenishment algorithm; it detects temporally changing pixels as active pixels and output them. An analog circuit for processing in each pixel and an entire sensor architecture have been designed. A first prototype of a VLSI sensor chip has been fabricated. Results of experiments using the prototype chip are shown.
