Permutation of measuring capacitors in a time-of-flight sensor

Abstract

A time of flight sensor device is capable of generating accurate propagation time information for emitted light pulses using a small number of measurement cycles by using multiple measuring capacitors to capture more return pulse information per pulse period. To mitigate the effects of mismatched measuring capacitors and reading paths, embodiments of the time of flight sensor device perform multiple measuring sequences per measurement operation, permutating the roles of the measuring capacitors for each of the measuring sequences. The data collected by the measuring capacitors for the multiple measuring sequences is then aggregated and used to compute the propagation time and corresponding distance. This technique mitigate yields accurate measurements despite mismatches between reading paths and measuring capacitors without the need to implement pixel-level calibration and compensation, thereby saving calibration time, memory space, and computing time.