US 12,442,926 B2
Time-of-flight depth sensing with improved linearity
Shingo Mandai, Mountain View, CA (US); Cristiano L Niclass, San Jose, CA (US); Nadav Fine, Herzliya (IL); Oz Barak, Tel Aviv (IL); and Rahmi Hezar, San Jose, CA (US)
Assigned to Apple Inc., Cupertino, CA (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on Dec. 12, 2021, as Appl. No. 17/548,541.
Claims priority of provisional application 63/145,504, filed on Feb. 4, 2021.
Prior Publication US 2022/0244391 A1, Aug. 4, 2022
Int. Cl. G01S 17/894 (2020.01); G01B 11/22 (2006.01); G01S 7/481 (2006.01); G01S 7/4865 (2020.01)
CPC G01S 17/894 (2020.01) [G01B 11/22 (2013.01); G01S 7/4816 (2013.01); G01S 7/4865 (2013.01)] 18 Claims
OG exemplary drawing
 
1. Optical sensing apparatus, comprising:
a radiation source, which is configured to direct a series of optical pulses toward a target scene;
a first array of single-photon detectors, which are configured to receive optical radiation that is reflected from the target scene and to output electrical pulses in response to photons that are incident thereon;
a second array of counters, which are configured to aggregate and count the electrical pulses output by the single-photon detectors over respective periods indicated by respective gating signals applied to the counters; and
control logic, which is configured to apply the respective gating signals to the counters, in each of a sequence of image frames, so as to cause different ones of the counters to aggregate and count the electrical pulses output by one or more of the single-photon detectors over different, respective gating intervals relative to each of the optical pulses, such that the second array of the counters generates, for the image frames in the sequence, respective frame histograms of the electrical pulses output by the single-photon detectors with histogram bins defined by the gating intervals,
wherein the control logic is configured to apply different temporal offsets between the optical pulses and the gating signals over the sequence of the image frames and to sum the frame histograms generated with the different temporal offsets so as to compute and output a cumulative histogram.