A high dynamic range CMOS image sensor with a novel pixel-level logarithmic counter memory

In this paper, we propose a CMOS image sensor that exploits multiple capture and spatially varying pixel exposures to achieve a dynamic range of 155 dB, 95 dB higher than a conventional CMOS image sensor. The proposed sensor also utilizes a novel pixel-level counter memory to enhance the sensor's dynamic range and fill factor. Here, the logarithms of counter values used in measurements of incident light intensities are approximated and stored in memory within each pixel. Since these logarithmic values can be represented by a smaller number of bits, each pixel has a smaller area dedicated to memory, allowing a higher fill factor. The proposed CMOS image sensor is well suited to outdoor automotive and mobile robotic applications.