WORKSHOP PAPER
Long-Range iToF Sensing with Hybrid Pulsed-CW Operation enabling High Dynamic Range, Ambient Light Rejection, and In-Chip Depth Calculation
Abstract
This paper presents a novel mode of operation for indirect-Time-of-Flight (iToF) sensors utilizing high peak power and low duty cycle pulsed illumination. The proposed hybrid mode mimics the response of conventional Continuous-Wave (CW) operation while providing extended dynamic range and doubling ambient light rejection. We demonstrate a 30m indoor and 20m outdoor operation with an eye-safe system using four vertical-cavity surface-emitting lasers (VCSELs). The depth calculation is done on-chip using the same algorithm pipeline that is used in iToF operation, and includes dual-normal frequency calculation for anti-aliasing.Keywords
iToF, sensors, hybrid mode, pulsed-CW operation, dynamic range, ambient light rejection, in-chip depth calculation, VCSELs,References
[1]) K. Mars et al., "A 648 x 484-Pixel 4-Tap Hybrid Time-of-Flight Image Sensor with 8 and 12 Phase Demodulation for Long-Range Indoor and Outdoor Operations", IISW2023, Crieff, Scotland, UK
[2]) K. Hatakeyama et al., "A Hybrid Indirect ToF Image Sensor for Long-Range 3D Depth Measurement under High Ambient Light Conditions", 2022 IEEE Symposium on VLSI Technology and Circuits. https://doi.org/10.1109/vlsitechnologyandcir46769.2022.9830139