Method and device for laser safety verification

Patent metadata

Field	Value
Publication number	US-11353591-B2
Application number	US-202017024418-A
Country	US
Kind code	B2
Filing date	Sep 17, 2020
Priority date	Sep 30, 2019
Publication date	Jun 7, 2022
Grant date	Jun 7, 2022

Abstract

The present disclosure relates to a method of laser safety verification for a depth map sensor, comprising illuminating, during a first illumination phase, using a laser illumination system, a first cluster of one or more first pixels of a pixel array of the depth map sensor, while not illuminating a second cluster, different from the first cluster, of one or more second pixels of the pixel array of the depth map sensor; and detecting, during the first illumination phase, a level of illumination of the second cluster.

First claim

What is claimed is:

1. A method of laser safety verification for a depth map sensor, the method comprising:
illuminating, during a first illumination phase, using a laser illumination system, a first cluster of one or more first pixels of a pixel array of the depth map sensor, while not illuminating a second cluster, different from the first cluster, of one or more second pixels of the pixel array of the depth map sensor; and
detecting, during the first illumination phase, a level of illumination of the second cluster.

2. The method of claim 1 , further comprising comparing the detected level of illumination of the second cluster, during the first illumination phase, with a first threshold value to verify safety of the laser illumination system.

3. The method of claim 2 , further comprising detecting, during the first illumination phase, a level of illumination of the first cluster, the first threshold value being a variable threshold having a level generated based on the detected level of illumination of the first cluster.

4. The method of claim 1 , further comprising:
illuminating, during a second illumination phase, using the laser illumination system, the second cluster, while not illuminating the first cluster; and
detecting, during the second illumination phase, a level of illumination of the first cluster.

5. The method of claim 4 , further comprising comparing the detected level of illumination of the first cluster, during the second illumination phase, with a second threshold value to verify safety of the laser illumination system.

6. The method of claim 5 , further comprising comparing the detected level of illumination of the second cluster, during the first illumination phase, with the second threshold value to verify the safety of the laser illumination system.

7. The method of claim 1 , wherein the depth map sensor comprises N clusters, including the first and second clusters, where N is equal to two or more, the method further comprising detecting, during the first illumination phase, a level of illumination of all N clusters except the first cluster.

8. The method of claim 7 , wherein the laser illumination system comprises N laser light sources.

9. The method of claim 8 , further comprising:
illuminating, during a second illumination phase, using the laser illumination system, the second cluster, while not illuminating the first cluster; and
detecting, during the second illumination phase, a level of illumination of the first cluster;
there being N illumination phases, including the first and second illumination phases, each illumination phase using a respective one of the N laser light sources.

10. The method of claim 1 , further comprising obtaining the level of illumination of the second cluster by reading the second pixels.

11. The method of claim 1 , further comprising obtaining the level of illumination of the second cluster by averaging outputs of the second pixels.

12. A non-transitory storage medium, storing computer instructions that, when executed by a processing device, cause the processing device to:
illuminate, during a first illumination phase, using a laser illumination system, a first cluster of one or more first pixels of a pixel array of a depth map sensor, while not illuminating a second cluster, different from the first cluster, of one or more second pixels of the pixel array of the depth map sensor; and
detect, during the first illumination phase, using the second cluster, a level of illumination of the second cluster.

13. The non-transitory storage medium of claim 12 , wherein the computer instructions, when executed by the processing device, cause the processing device to compare the detected level of illumination of the second cluster, during the first illumination phase, with a first threshold value to verify safety of the laser illumination system.

14. The non-transitory storage medium of claim 13 , wherein the computer instructions, when executed by the processing device, cause the processing device to detect, during the first illumination phase, using the first cluster, a level of illumination of the first cluster, the first threshold value being a variable threshold having a level generated based on the detected level of illumination of the first cluster.

15. The non-transitory storage medium of claim 12 , wherein the computer instructions, when executed by the processing device, cause the processing device to:
illuminate, during a second illumination phase, using the laser illumination system, the second cluster, while not illuminating the first cluster; and
detect, during the second illumination phase, using the first cluster, a level of illumination of the first cluster.

16. The non-transitory storage medium of claim 15 , wherein the computer instructions, when executed by the processing device, cause the processing device to compare the detected level of illumination of the first cluster, during the second illumination phase, with a second threshold value to verify safety of the laser illumination system.

17. A device comprising:
a laser illumination system;
a first cluster of one or more first pixels of a pixel array of a depth map sensor,
a second cluster, different from the first cluster, of one or more second pixels of the pixel array of the depth map sensor; and
a control circuit configured to:
illuminate, during a first illumination phase, using the laser illumination system, the first cluster while not illuminating the second cluster; and
detect, during the first illumination phase, using the second cluster, a level of illumination of the second cluster.

18. The device of claim 17 , wherein the laser illumination system comprises a least one vertical-cavity surface-emitting laser.

19. The device of claim 17 , wherein each pixel comprises at least one single-photon avalanche diode.

20. The device of claim 17 , wherein the control circuit is configured to compare the detected level of illumination of the second cluster, during the first illumination phase, with a first threshold value to verify safety of the laser illumination system.

21. The device of claim 20 , wherein the control circuit is configured to detect, during the first illumination phase, using the first cluster, a level of illumination of the first cluster, the first threshold value being a variable threshold having a level generated based on the detected level of illumination of the first cluster.

22. The device of claim 17 , wherein the control circuit is configured to:
illuminate, during a second illumination phase, using the laser illumination system, the second cluster, while not illuminating the first cluster; and
detect, during the second illumination phase, using the first cluster, a level of illumination of the first cluster.

23. The device of claim 22 , wherein the control circuit is configured to compare the detected level of illumination of the first cluster, during the second illumination phase, with a second threshold value to verify safety of the laser illumination system.

Assignees

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

Inventors

• Townsend Christopher
• Mellot Pascal

Classifications

• G01S7/497

  Means for monitoring or calibrating · CPC title

• G01S17/89 Primary

  for mapping or imaging · CPC title

• G01S17/10

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

• G01S7/4816

  of receivers alone · CPC title

• G01S17/42

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) · CPC title