Beam scanning methods for improved eye safety in LiDAR systems

Patent metadata

Field	Value
Publication number	US-12235362-B2
Application number	US-201916663814-A
Country	US
Kind code	B2
Filing date	Oct 25, 2019
Priority date	Oct 26, 2018
Publication date	Feb 25, 2025
Grant date	Feb 25, 2025

Abstract

A LiDAR system includes an array of optical emitters, an objective lens optically coupling each optical emitter to a respective unique portion of a field of view, an optical switching network coupled between a laser and the array of optical emitters and a controller coupled to the optical switching network and configured to cause the optical switching network to route light from the laser to a sequence of the optical emitters according to a dynamically varying temporal pattern and to vary the temporal pattern in a way that reduces risk of eye injury from the laser light.

First claim

What is claimed is:

1. A LiDAR system having a field of view, the LiDAR system comprising:
a laser;
an array of optical emitters;
an objective lens optically coupling each optical emitter of the array of optical emitters to a respective unique portion of the field of view;
an optical switching network coupled between the laser and the array of optical emitters;
a controller coupled to the optical switching network and configured to cause the optical switching network to route light from the laser to a sequence of optical emitters of the array of optical emitters according to a dynamically varying temporal pattern; and
an optical receiver coupled to the optical switching network and configured to receive light reflected from the field of view.

2. A LiDAR system according to claim 1 , wherein the controller is configured to dynamically vary the temporal pattern so as to vary a repetition rate at which the light from the laser illuminates a given pixel of the field of view.

3. A LiDAR system according to claim 1 , wherein the controller is configured to dynamically vary the temporal pattern so as to vary pulse width of the light from the laser for a given pixel of the field of view.

4. A LiDAR system according to claim 1 , wherein the controller is configured to dynamically vary the temporal pattern so as to vary dwell time of the light from the laser for a given pixel of the field of view.

5. A LiDAR system according to claim 1 , wherein the controller is configured to dynamically vary the temporal pattern so as to vary a revisit rate at which the light from the laser illuminates a given pixel of the field of view.

6. A LiDAR system according to claim 1 , wherein the controller is configured to dynamically vary the temporal pattern so as to vary dwell time and revisit rate of the light from the laser for a given pixel of the field of view, such that the dwell time and revisit rate are varied in inverse proportions to maintain constant reliability and accuracy.

7. A LiDAR system according to claim 6 , wherein the controller is further configured to analyze consecutive return pulses of the light reflected from the field of view together.

8. A LiDAR system according to claim 1 , wherein the controller is configured to automatically dynamically vary the temporal pattern for a portion of the field of view designated as potentially including an eye of a living being.

9. A LiDAR system according to claim 8 , wherein the controller is further configured to automatically detect a portion of the field of view that includes a living being and designate the portion of the field of view as potentially including an eye of a living being.

10. A LiDAR system according to claim 9 , further comprising a digital camera, wherein the controller is configured to automatically analyze image date from the digital camera to automatically detect the portion of the field of view that includes the living being.

11. A LiDAR system according to claim 1 , wherein the controller is configured to cause the optical switching network to route the light from the laser to the sequence of optical emitters of the array of optical emitters such that the field of view is scanned horizontally non-sequentially.

12. A LiDAR system according to claim 1 , wherein the controller is configured to cause the optical switching network to route the light from the laser to the sequence of optical emitters of the array of optical emitters such that the field of view is scanned vertically non-sequentially.

13. A LiDAR system according to claim 1 , wherein the controller is configured to cause the optical switching network to route the light from the laser to the sequence of optical emitters of the array of optical emitters such that the field of view is scanned horizontally non-sequentially and vertically non-sequentially.

14. A LiDAR system according to claim 1 , wherein the controller is configured to cause the optical switching network to route the light from the laser to the sequence of optical emitters of the array of optical emitters such that the field of view is scanned such that a maximum of three horizontally adjacent pixels are illuminated in sequence and a maximum of three vertically adjacent pixels are illuminated in sequence.

15. A LiDAR system according to claim 1 , wherein the controller is configured to cause the optical switching network to route the light from the laser to the sequence of optical emitters of the array of optical emitters such that the field of view is scanned according to a non-raster pattern.

16. A LiDAR system according to claim 1 , wherein the controller is configured to cause the optical switching network to route the light from the laser to the sequence of optical emitters of the array of optical emitters such that the field of view is scanned according to a pseudorandom pattern.

17. A LiDAR system according to claim 1 , wherein the controller is configured to dynamically vary the temporal pattern at least in part according to a speed of translation of the LiDAR system.

18. A LiDAR system according to claim 1 , wherein the controller is configured to dynamically vary the temporal pattern at least in part according to an expected density of human beings in the field of view.

19. A LiDAR system according to claim 1 , wherein the controller is configured to dynamically vary the temporal pattern at least in part according to a degree of reliability of range information is needed.

20. A LiDAR system according to claim 1 , wherein the controller is configured to dynamically vary the temporal pattern differently for respective different non-overlapping regions of the field of view.

21. A LiDAR system according to claim 20 , wherein the controller is configured to dynamically vary the temporal pattern differently for the respective different non-overlapping regions of the field of view based at least in part on whether the respective regions are designated as potentially including an eye of a living being.

Assignees

• Charles Stark Draper Laboratory Inc

Inventors

• Moebius Michael G
• Spector Steven J
• Byrnes Steven J
• Bessette Christopher
• Lennox Scott Evan
• Sinclair Matthew A
• Rogomentich Francis J

Classifications

• H01S3/1305

  Feedback control systems · CPC title

• G01S13/867

  Combination of radar systems with cameras · CPC title

• G01S13/865

  Combination of radar systems with lidar systems · CPC title

• G01S17/26

  wherein the transmitted pulses use a frequency-modulated or phase-modulated carrier wave, e.g. for pulse compression of received signals · CPC title

• G01S17/93

  for anti-collision purposes · CPC title