학술논문

A Direct Time-of-Flight Image Sensor With In-Pixel Surface Detection and Dynamic Vision
Document Type
Periodical
Source
IEEE Journal of Selected Topics in Quantum Electronics IEEE J. Select. Topics Quantum Electron. Selected Topics in Quantum Electronics, IEEE Journal of. 30(1: Single-Photon Technologies and Applications):1-11 Jan, 2024
Subject
Engineered Materials, Dielectrics and Plasmas
Photonics and Electrooptics
Logic gates
Histograms
Single-photon avalanche diodes
Photonics
Sensors
Sensor arrays
Image sensors
3-D ranging
direct time-of-flight (dToF)
light detection and ranging (LIDAR)
single-photon avalanche diode (SPAD)
SPAD array
Language
ISSN
1077-260X
1558-4542
Abstract
3D flash LIDAR is an alternative to the traditional scanning LIDAR systems, promising precise depth imaging in a compact form factor, and free of moving parts, for applications such as self-driving cars, robotics and augmented reality (AR). Typically implemented using single-photon, direct time-of-flight (dToF) receivers in image sensor format, the operation of the devices can be hindered by the large number of photon events needing to be processed and compressed in outdoor scenarios, limiting frame rates and scalability to larger arrays. We here present a $64 \times 32$ pixel ($256 \times 128$ SPAD) dToF imager that overcomes these limitations by using pixels with embedded histogramming, which lock onto and track the return signal. This reduces the size of output data frames considerably, enabling maximum frame rates in the 10 kFPS range or 100 kFPS for direct depth readings. The sensor offers selective readout of pixels detecting surfaces, or those sensing motion, akin to dynamic vision sensors that report changes in light intensity, leading to reduced power consumption and off-chip processing requirements. We demonstrate the application of the sensor in mid-range LIDAR.