Method and apparatus for processing a histogram output from a detector sensor

Patent metadata

Field	Value
Publication number	US-12367257-B2
Application number	US-202318466522-A
Country	US
Kind code	B2
Filing date	Sep 13, 2023
Priority date	Mar 1, 2017
Publication date	Jul 22, 2025
Grant date	Jul 22, 2025

Abstract

A method includes receiving a histogram output from a detector sensor, and calculating a median point of a pulse waveform within the histogram. The pulse waveform has an even probability distribution over at least one quantization step of the histogram around the median point. A corresponding apparatus can include a detector sensor and a co-processor coupled to the detector sensor.

First claim

What is claimed is:

1. A method for processing a histogram output from a detector sensor, the method comprising:
sending a light signal to an object within a field-of-view of the detector sensor;
receiving a reflected light pulse with the detector sensor;
receiving histogram data from the detector sensor; and
filtering the histogram data to remove at least one parasitic path component from the histogram data, wherein filtering the histogram data to remove at least one parasitic path component comprises over-correcting an intensity and widening the at least one parasitic path component.

2. The method as claimed in claim 1 , further comprising capturing at least one histogram comprising the at least one parasitic path component in order to isolate the at least one parasitic path component.

3. The method as claimed in claim 2 , further comprising receiving histogram data, the histogram data comprising at least one histogram comprising at least one parasitic path component, wherein capturing at least one histogram comprising at least one parasitic path component in order to isolate the at least one parasitic path component comprises filtering the at least one histogram comprising at least one parasitic path component to isolate the at least one parasitic path component.

4. The method as claimed in claim 3 , wherein the histogram data further comprises at least one further histogram comprising at least one object and the at least one parasitic path components, wherein filtering the histogram data further comprises filtering the at least one further histogram using the filtered isolated parasitic path components to remove the at least one parasitic path component and retain the at least one object component.

5. The method as claimed in claim 2 , wherein capturing at least one histogram comprises:
removing from the at least one histogram an ambient value to generate an ambient free histogram; and
normalizing the ambient free histogram based on a number of sensor elements within the detector which generated the at least one histogram to generate a normalized histogram.

6. The method as claimed in claim 5 , wherein filtering the at least one further histogram comprises:
scaling the normalized histogram by a number of sensor elements within the detector sensor which generated the at least one further histogram to generate a parasitic path histogram; and
subtracting the parasitic path histogram from the at least one further histogram to remove the at least one parasitic path component from the at least one histogram.

7. The method as claimed in claim 2 , wherein capturing at least one histogram comprising at least one parasitic path component in order to isolate the parasitic path components comprises determining a parasitic path function modelling the parasitic path components over the detector sensor and histogram bins, and filtering the histogram data further comprises applying the parasitic path function modelling the parasitic path components over the detector sensor and histogram bins.

8. The method as claimed in claim 7 , wherein determining a parasitic path function modelling the parasitic path components over the detector sensor and histogram bins comprises:
capturing at least one histogram comprising at least one parasitic path component in order to isolate the parasitic path components for at least three positions over the detector sensor; and spatially interpolating the parasitic path components for at least three positions over the detector sensor to generate the parasitic path function.

9. The method as claimed in claim 1 , further comprising:
determining a reference measurement associated with a phase of the at least one parasitic path component; and shifting the at least one parasitic path component by the phase value prior to filtering the histogram.

10. The method as claimed in claim 1 , wherein receiving the histogram data from the detector sensor comprises receiving a cover glass device test histogram of cross-talk only components.

11. An apparatus configured to measure a distance to an object, the apparatus comprising:
a light source configured to send a light signal to the object;
a detector sensor configured to receive a reflected light signal from the object;
a filter configured to:
filter histogram data from the detector sensor to remove at least one parasitic path component from the histogram data; and
capture at least one histogram comprising the at least one parasitic path component by:
receiving a cover glass device test histogram of cross-talk only components, determining the histogram is cross-talk only components, or receiving at least one additional sensor output determining no other target objects obstructing a cross-talk portion of the histogram.

12. The apparatus as claimed in claim 11 , further comprising an input configured to receive the histogram data, the histogram data comprising at least one histogram comprising at least one parasitic path component, wherein the filter is further configured to filter the at least one histogram comprising parasitic path components to isolate the parasitic path components.

13. The apparatus as claimed in claim 12 , wherein the histogram data further comprises at least one further histogram comprising at least one object and at least one parasitic path component, wherein the filter configured to filter the histogram data is configured to filter the at least one further histogram using the filtered isolated parasitic path components to remove the at least one parasitic path component and retain the at least one object component.

14. The apparatus as claimed in claim 11 , wherein the detector sensor comprises an array of single photon avalanche diodes.

15. A method for processing a histogram output from a detector sensor, the method comprising:
sending a light signal to an object within a field-of-view of the detector sensor;
receiving a reflected light pulse with the detector sensor;
receiving histogram data from the detector sensor;
capturing a histogram from the histogram data, the histogram comprising a parasitic path component, wherein capturing the histogram comprising the parasitic path component comprises:
receiving a cover glass device test histogram of cross-talk only components,
determining the histogram is cross-talk only components, or
receiving at least one additional sensor output determining no other target objects obstructing a cross-talk portion of the histogram; and

removing the parasitic path component from the histogram data.

16. The method as claimed in claim 15 , wherein determining the histogram is cross-talk only components comprises determining a lack of a change in histogram pulse positions.

17. The method as claimed in claim 15 , wherein determining the histogram is cross-talk only components comprises determining a lack of a change in histogram pulse widths.

18. The method as claimed in claim 15 , wherein determining the histogram is cross-talk only components comprises determining a lack of a change in histogram intensity information.

19. The method as claimed in claim 15 , wherein removing the parasitic path component from the histogram data is performed by: isolating the parasitic path component in the histogram; and filtering the histogram data to remove the parasitic path component and retain at least one object component.

20. The method as claimed in claim 15 , further comprising normalizing the histogram comprising the parasitic path component by dividing histogram count values by a number of en

Assignees

• St Microelectronics Grenoble 2
• St Microelectronics Res & Dev Ltd

Inventors

• Moore John Kevin
• Lee Sam
• Mellot Pascal
• Baxter Donald
• Mcleod Stuart
• Dargan Kenneth

Classifications

• G01S7/497

  Means for monitoring or calibrating · CPC title

• G01S7/4876

  by removing unwanted signals (G01S7/495 takes precedence) · CPC title

• G01S7/4865

  Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak (peak detection in noise, signal conditioning G01S7/487) · CPC title

• G01S7/4813

  Housing arrangements · CPC title

• G01S17/10

  using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) · CPC title