This paper presents a high dynamic range CMOS image sensor that implements an in-pixel content-aware adaptive global tone mapping algorithm during image capture operation. The histogram of the previous frame of an auxiliary image, which contains time stamp information, is employed as an estimation of the probability of illuminations impinging pixels at the present frame. The compression function of illuminations, namely tone mapping curve, is calculated using this histogram. A QCIF resolution proof-of-concept prototype has been fabricated using a 0.35 μm opto-flavored standard technology. The sensor is capable of mapping scenes with a maximum intra-frame dynamic range of 151 dB (25 bits/pixel in linear representation) by compressing them to only 7 bits/pixel, while keeping visual quality in details and contrast. The in-pixel on-the-fly fully parallel tone mapping achieves high-frame rate allowing real-time high dynamic range video (120 dB at 30 frames/s).
Journal Paper -
IEEE Sensors Journal, vol. 15, no. 1, pp 180-195, 2014
DOI: 10.1109/JSEN.2014.2340875 » doi