A 1/3´´ VGA linear wide dynamic range CMOS image sensor implementing a predictive multiple sampling algorithm with overlapping integration intervals

Many tasks performed by machine vision systems involve processing of natural scenes with large intra-frame illumination ratios. Thus, wide dynamic range visible spectrum image sensors are required to achieve adequate processing performance and reliability. An image sensor implementing an algorithm that linearly increases the illumination dynamic range of solid-state pixels is presented. Optimal exposure is achieved with a predictive pixel saturation decision that allows for multiple integration intervals of different duration to run concurrently for different pixels while keeping the sensor frame rate constant. A proof-of-concept chip was fabricated in a 0.18-μm CMOS process. Added functionality to standard imagers is mainly concentrated off-pixel so fill factor is not sacrificed. Measured data corroborates the algorithm functionality.