US 11,754,720 B2
Time-to-digital converter for depth sensing
Augusto Ronchini Ximenes, Seattle, CA (US); and Michael Hall, Bellevue, WA (US)
Assigned to Meta Platforms Technologies, LLC, Menlo Park, CA (US)
Filed by Meta Platforms Technologies, LLC, Menlo Park, CA (US)
Filed on Nov. 29, 2021, as Appl. No. 17/536,985.
Application 17/536,985 is a continuation of application No. 16/859,487, filed on Apr. 27, 2020, granted, now 11,215,712.
Prior Publication US 2022/0082699 A1, Mar. 17, 2022
Int. Cl. G01S 17/00 (2020.01); G01S 17/894 (2020.01); G01S 7/4865 (2020.01); G06T 7/80 (2017.01); G06T 7/521 (2017.01)
CPC G01S 17/894 (2020.01) [G01S 7/4865 (2013.01); G06T 7/521 (2017.01); G06T 7/80 (2017.01)] 19 Claims
OG exemplary drawing
 
1. A depth camera assembly (DCA) comprising:
a sensor including:
a plurality of pixels configured to capture images of a local area, and
an array of time-to-digital converters coupled to the plurality of pixels, each time-to-digital converter in the array including an oscillator and a counter, each pixel in a group of pixels of the plurality of pixels associated with a respective multiplexer of a plurality of multiplexers, the respective multiplexer configured to:
select between a first signal from that pixel, a second signal from the oscillator and a third signal from another counter of another time-to-digital converter in the array as an output signal, and
provide the output signal to the counter to increment a value of the counter; and
a controller configured to:
estimate, during a first portion of an image frame, a plurality of depth values for the plurality of pixels, each depth value of the plurality of depth values estimated based on the value of the counter,
perform, during a second portion of the image frame, intensity measurements for the plurality of pixels, and
calibrate, during a third portion of the image frame, the plurality of depth values using the intensity measurements.