SPAD-based HDR Imaging

MDPI Sensors keep publishing expanded papers from 2017 International Image Sensor Workshop. ST Micro and University of Edinburgh present "High Dynamic Range Imaging at the Quantum Limit with Single Photon Avalanche Diode-Based Image Sensors" by Neale A.W. Dutton, Tarek Al Abbas, Istvan Gyongy, Francescopaolo Mattioli Della Rocca, and Robert K. Henderson.

"This paper examines methods to best exploit the High Dynamic Range (HDR) of the single photon avalanche diode (SPAD) in a high fill-factor HDR photon counting pixel that is scalable to megapixel arrays. The proposed method combines multi-exposure HDR with temporal oversampling in-pixel. We present a silicon demonstration IC with 96 × 40 array of 8.25 µm pitch 66% fill-factor SPAD-based pixels achieving >100 dB dynamic range with 3 back-to-back exposures (short, mid, long). Each pixel sums 15 bit-planes or binary field images internally to constitute one frame providing 3.75× data compression, hence the 1k frames per second (FPS) output off-chip represents 45,000 individual field images per second on chip. Two future projections of this work are described: scaling SPAD-based image sensors to HDR 1 MPixel formats and shrinking the pixel pitch to 1–3 µm."