Dutton Neale A W, Al Abbas Tarek, Gyongy Istvan, Mattioli Della Rocca Francescopaolo, Henderson Robert K
STMicroelectronics Imaging Division, Tanfield, Edinburgh EH3 5DA, UK.
School of Engineering, The University of Edinburgh, Edinburgh EH9 3JL, UK.
Sensors (Basel). 2018 Apr 11;18(4):1166. doi: 10.3390/s18041166.
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.
本文研究了在高填充因子的高动态范围（HDR）光子计数像素中最佳利用单光子雪崩二极管（SPAD）高动态范围的方法，该像素可扩展至百万像素阵列。所提出的方法将多曝光HDR与像素内的时间过采样相结合。我们展示了一款基于硅的演示集成电路，其具有96×40阵列的间距为8.25 µm、填充因子为66%的基于SPAD的像素，通过3次连续曝光（短、中、长）实现了>100 dB的动态范围。每个像素在内部对15个位平面或二进制场图像进行求和以构成一帧，实现了3.75倍的数据压缩，因此每秒1000帧（FPS）的片外输出代表芯片上每秒45,000个单独的场图像。本文还描述了这项工作的两个未来展望：将基于SPAD的图像传感器扩展到HDR 100万像素格式，以及将像素间距缩小到1 - 3 µm。
