Light detection and ranging (LiDAR) system and method

• US 10,473,766 B2
• Filed: 06/27/2017
• Issued: 11/12/2019
• Est. Priority Date: 03/13/2017
• Status: Active Grant

• Current Assignee: Charles Stark Draper Laboratory Incorporated
• Original Assignee: Charles Stark Draper Laboratory Incorporated
• Inventors: Spector, Steven J.
• Primary Examiner(s): Abraham, Samantha K
• Application Number:
  US15/634,672
• Publication Number:
  US 20180259626A1
• Time in Patent Office: 868 Days
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/4816 of receivers alone
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/484 Transmitters
• CPC Class Codes: G01S 7/4863 Detector arrays, e.g. charge-transfer gates

Abstract

A LiDAR system and scanning method creates a two-dimensional array of light spots. A scan controller causes the array of light spots to move back and forth so as to complete a scan of the scene. The spots traverse the scene in the first dimensional direction and in the second dimensional direction without substantially overlapping points in the scene already scanned by other spots in the array. An arrayed micro-optic projects the light spots. Receiver optics includes an array of optical detection sites. The arrayed micro-optic and the receiver optics are synchronously scanned while maintaining a one-to-one correspondence between light spots in the two dimensional array and optical detection sites in the receiver optics.

Claims

1. A light detection and ranging (LiDAR) system comprising:

a light source;

an arrayed micro-optic configured to receive light from the light source so as to produce and project a two dimensional array of light spots on a scene, wherein the two dimensions of the array includes a first dimensional direction and a second dimensional direction;

receiver optics having an array of optical detection sites configured so as to be suitable for establishing a one-to-one correspondence between light spots in the two dimensional array and optical detection sites in the receiver optics;

a scanner configured to physically oscillate the arrayed micro-optic and the receiver optics synchronously to scan;

(a) the two dimensional array of light spots and (b) the receiver optics so as to maintain the one-to-one correspondence; and

a scan controller operable to cause the scanner to move the array of light spots back and forth so as to complete a scan of the scene wherein the spots traverse the scene in the first dimensional direction and in the second dimensional direction no more than 150% of the distance between adjacent spots in the first dimensional direction and in the second dimensional direction, respectively.

2. The LiDAR system according to claim 1 wherein the scan controller is operable to cause the scanner to move the array of light spots back and forth so as to complete a scan of the scene wherein the spots traverse the scene in the first dimensional direction and in the second dimensional direction no more than 110% of the distance between adjacent spots in the first dimensional direction and in the second dimensional direction, respectively.

3. The LiDAR system according to claim 1 wherein the scan controller is operable to cause the scanner to move the array of light spots back and forth so as to complete a scan of the scene wherein the spots traverse the scene in the first dimensional direction and in the second dimensional direction no more than the distance between adjacent spots in the first dimensional direction and in the second dimensional direction, respectively.

4. The LiDAR system according to claim 1 wherein the back and forth movement of the array of light spots comprises a raster path.

5. The LiDAR system according to claim 1 wherein the receiver optics includes a mask defining a plurality of transparent apertures arranged according to the two dimensional array, the plurality of transparent apertures limiting visibility by each optical detection site to a single corresponding light spot in the two dimensional array.

6. The LiDAR system according to claim 1 wherein the first dimensional direction is horizontal and the second dimensional direction is vertical.

7. The LiDAR system according to claim 1, wherein the scanner comprises an x-y stage.

8. The LiDAR system according to claim 1, wherein the scanner comprises a compound lens.

9. The LiDAR system according to claim 1, wherein the receiver optics comprises a pixelated optical sensor array.

10. The LiDAR system according to claim 1, wherein the arrayed micro-optic comprises a diffractive optic.

11. The LiDAR system according to claim 1, wherein the arrayed micro-optic comprises a lens array.

12. The LiDAR system according to claim 1, wherein the arrayed micro-optic comprises an aperture array.

13. The LiDAR system according to claim 1, further comprising a LiDAR controller for calculating distance to the light spots on the scene from time-of-flight of light received at the receiver optics.

14. A method for scanning with a light detection and ranging (LiDAR) system comprising:

activating a light from a light source;

projecting the light through an arrayed micro-optic to produce and project a two dimensional array of light spots on a scene, the two dimensions of the array including a first dimensional direction and a second dimensional direction;

receiving light from the array of light spots in one-to-one correspondence to an array of optical detection sites in receiver optics;

physically oscillating the arrayed micro-optic and the receiver optics synchronously to scan the two dimensional array of light spots and the receiver optics so as to maintain the one-to-one correspondence and to complete a scan of the scene wherein the spots traverse the scene in the first dimensional direction and in the second dimensional direction no more than 150% of the distance between adjacent spots in the first dimensional direction and in the second dimensional direction, respectively.

15. The scanning method according to claim 14 wherein the physically oscillating completes a scan of the scene wherein the spots traverse the scene in the first dimensional direction and in the second dimensional direction no more than 110% of the distance between adjacent spots in the first dimensional direction and in the second dimensional direction, respectively.

16. The scanning method according to claim 14 wherein the physically oscillating completes a scan of the scene wherein the spots traverse the scene in the first dimensional direction and in the second dimensional direction no more than the distance between adjacent spots in the first dimensional direction and in the second dimensional direction, respectively.

17. The scanning method according to claim 14, further comprising calculating distance to the light spots on the scene from time-of-flight of light received at the receiver optics.

18. A light detection and ranging (LiDAR) system comprising:

a light source;

means for receiving light from the light source and for projecting a two dimensional array of light spots on a scene, wherein the two dimensions of the array includes a first dimensional direction and a second dimensional direction;

receiver optics having an array of optical detection sites configured so as to be suitable for establishing a one-to-one correspondence between light spots in the two dimensional array and optical detection sites in the receiver optics;

oscillating means for physically oscillating the receiver optics and the means for receiving and projecting to synchronously scan the two dimensional array of light spots and the receiver optics so as to maintain the one-to-one correspondence; and

a scan controller operable to cause the oscillating means to move the array of light spots back and forth so as to complete a scan of the scene wherein the spots traverse the scene in the first dimensional direction and in the second dimensional direction no more than 110% of the distance between adjacent spots in the first dimensional direction and in the second dimensional direction, respectively.

19. The LiDAR system according to claim 18, wherein the means for receiving and projecting comprises a diffractive optic.

20. The LiDAR system according to claim 18, wherein the means for receiving and projecting comprises a lens array.

21. The LiDAR system according to claim 18, wherein the means for receiving and projecting comprises an aperture array.

22. The LiDAR system according to claim 18, wherein the oscillating means comprises an x-y stage.

23. The LiDAR system according to claim 18, further comprising a LiDAR controller for calculating distance to the light spots on the scene from time-of-flight of light received at the receiver optics.