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

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.