A 134×132 4-Tap CMOS Indirect Time-of-Flight Range Imager Using In-Pixel Memory Array with 10 Kfps High-Speed Mode and High Precision Mode

Abstract

This article presents a prototype 4-tap indirect time-of-flight (iToF) CMOS imager with high-speed (HS) range imaging capacity. The sensor features an HS charge modulator, in-pixel memory array, and sub-frame ToF operation, enabling up to 10 Kfps range imaging with eight recording frames and < 1.82% depth noise for 0.3-1.4 m range under HS mode. This sensor also operates in high-precision (HP) mode, achieving < 1.77% depth noise for the 0.4-5.4 m range at 90 frames/s by averaging the subframe signals. With a pixel size of 22.4{H} \times 16{V}\,\,\mu \text{m} and 134{H} \times 132{V}\,\,4 -tap pixel array, the sensor successfully demonstrated precise depth imaging under HP mode and clear 3-D imaging for rapid motion objects under HS mode. The potential application of the sensor and future improvements are also discussed.