US 12,092,769 B2
Photodetectors and methods and ranging devices and methods
Takehito Nonomura, Nishitama-gun (JP)
Assigned to NIKON VISION CO., LTD., Tokyo (JP)
Filed by NIKON VISION CO., LTD., Tokyo (JP)
Filed on Nov. 24, 2020, as Appl. No. 17/103,009.
Application 17/103,009 is a continuation of application No. PCT/JP2018/020821, filed on May 30, 2018.
Prior Publication US 2021/0080553 A1, Mar. 18, 2021
Int. Cl. G01S 7/4863 (2020.01); G01S 7/48 (2006.01); G01S 7/4865 (2020.01); G01S 7/487 (2006.01); G01S 17/08 (2006.01); G01S 17/10 (2020.01)
CPC G01S 7/4863 (2013.01) [G01S 7/4808 (2013.01); G01S 7/4865 (2013.01); G01S 7/4873 (2013.01); G01S 17/08 (2013.01); G01S 17/10 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A photodetector comprising:
a projector configured to emit light to an object for a plurality of times;
a detector configured to detect reflected light from the object; and
a processor programmed to, for each light emission from the projector:
count, for a sequence of predetermined elapsed times from the light emission, an occurrence of a first event in which intensity of a detection signal output from the detector exceeds a first threshold;
count, for the sequence of predetermined elapsed times from the light emission and simultaneously with the count of the occurrence of the first event, an occurrence of a second event in which the intensity falls below a second threshold different in value than the first threshold, the intensity of the detection signal being greater than zero at both the first threshold and the second threshold;
integrate the counts of the occurrence of the first event for the plurality of times of light emission for each elapsed time to determine a positive histogram;
integrate the counts of the occurrence of the second event for the plurality of times of light emission for each elapsed time to determine a negative histogram; and
determine a detection time from the light emission to detection of the reflected light by the detector based on the positive histogram and the negative histogram.