CMOS image sensor with adaptive readout scheme for low power applications

An adaptive readout scheme for low-power CMOS image sensors is proposed in this paper. In the first step, the entire pixel array is partitioned into square blocks. Subsequently, the intensity range of each block is divided into a fix number of bins which are adapted to the intensity range of the block. For this purpose, the maximum and minimum intensity values in each block are obtained using winner take all circuit.The proposed scheme is implemented and simulated on standard test images. The observed peak signal-to-noise ratio for the Cameraman and Thermal image is 40.37 dB and 41.16 dB, respectively for 8×8 block size and 16 bins, with 54% saving in the total power compared to the conventional readout. An additional power saving can be observed by reducing the total number of threshold levels.