US 12,078,720 B2
Systems, methods, and media for single photon depth imaging with improved precision in ambient light
Anant Gupta, Madison, WI (US); Atul Ingle, Madison, WI (US); Andreas Velten, Madison, WI (US); and Mohit Gupta, Madison, WI (US)
Assigned to WISCONSIN ALUMNI RESEARCH FOUNDATION, Madison, WI (US)
Filed by Wisconsin Alumni Research Foundation, Madison, WI (US)
Filed on Mar. 8, 2019, as Appl. No. 16/297,320.
Prior Publication US 2020/0284907 A1, Sep. 10, 2020
Int. Cl. G01S 17/10 (2020.01); G01S 7/484 (2006.01); G01S 7/486 (2020.01); G01S 17/89 (2020.01); H01L 31/107 (2006.01)
CPC G01S 17/10 (2013.01) [G01S 7/484 (2013.01); G01S 7/4868 (2013.01); G01S 17/89 (2013.01); H01L 31/107 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A system for determining depths, comprising:
a light source;
a detector configured to detect arrival of individual photons;
an attenuation element configured to provide a variable intensity attenuation factor to remove pile-up of detected photons and decrease an error associated with a calculation of depth,
wherein an intensity of light perceived by the detector corresponds to a product of the attenuation factor and an intensity of light perceived by the detector in the absence of attenuation by the attenuation element; and
a processor that is programmed to:
(a) determine an ambient light intensity associated with a scene point;
(b) calculate an attenuation factor based on the ambient light intensity;
(c) estimate a depth of the scene point based on a multiplicity of photon arrival times determined using the detector during a period of time during which light incident on the detector is attenuated by an attenuation factor selected based on the calculated attenuation factor and during which the light source is configured to periodically emit a pulse of light toward the scene point;
(d) repeat (a) through (c) for each of a multiplicity of scene points.