Devices and methods for providing depth mapping with scanning laser image projection

Patent metadata

Field	Value
Publication number	US-10145680-B2
Application number	US-201615236133-A
Country	US
Kind code	B2
Filing date	Aug 12, 2016
Priority date	Aug 12, 2016
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

Devices and methods are described herein for combining image projection with surface scanning. In general, the devices and methods utilize at least one source of laser light to generate a laser beam, and scanning mirror(s) that reflect the laser beam into a pattern of scan lines. The source of light is controlled to selectively generate projected image pixels during a first portion of the pattern of scan lines, and to selectively generate depth mapping pulses during a second portion of the pattern of scan lines. The projected image pixels generate a projected image, while the depth mapping pulses are reflected from the surface, received, and used to generate a 3-dimensional point clouds that describe the measured surface depth at each point. Thus, during each scan of the pattern both a projected image and a surface depth map can be generated.

First claim

What is claimed is:

1. A scanning laser projector, comprising:
at least one source of laser light, the at least one source of laser light configured to generate a laser beam;
at least one scanning mirror configured to reflect the laser beam;
a drive circuit configured to provide an excitation signal to excite motion of the at least one scanning mirror to reflect the laser beam in a pattern of scan lines;
a pixel drive generator, the pixel drive generator configured to control the at least one source of laser light to selectively generate projected image pixels with the laser beam and selectively generate depth mapping pulses with the laser beam, and wherein the pixel drive generator is configured to generate projected image pixels during a first portion of the pattern of scan lines and generate depth mapping pulses during a second portion of the pattern of scan lines; and
a depth mapping device configured to receive reflections of the depth mapping pulses from a surface and generate a 3-dimensional point cloud of the surface based at least in part on timing of the received reflections of the depth mapping pulses from the surface.

2. The scanning laser projector of claim 1 , wherein the first portion of the pattern of scan lines comprises scan lines moving in a first direction and wherein the second portion of the pattern of scan lines comprises scan lines moving in a second direction, where the first direction and the second direction are opposite directions.

3. The scanning laser projector of claim 1 , wherein the first portion of the pattern of scan lines and the second portion of the pattern of scan lines are horizontal scan lines interlaced together.

4. The scanning laser projector of claim 1 , wherein the first portion of the pattern of scan lines comprises scan lines during an active display period and wherein the second portion of the pattern of scan lines comprises scan lines during a vertical retrace period.

5. The scanning laser projector of claim 1 , wherein the first portion of the pattern of scan lines and the second portion of the pattern of scan lines comprises generating projected image pixels and depth mapping pulses in each scan line.

6. The scanning laser projector of claim 1 , wherein the mapping device generates the 3-dimensional point cloud of the surface by calculating a time of flight for a return of the depth mapping pulses in the laser beam.

7. The scanning laser projector of claim 1 , wherein the motion of the at least one scanning mirror has a horizontal scan rate, a horizontal scan amplitude, a vertical scan rate, and a vertical scan amplitude, and wherein the drive circuit is further configured to dynamically adjust at least one of the horizontal scan rate, the horizontal scan amplitude, the vertical scan rate, and the vertical scan amplitude to modify characteristics of the 3-dimensional point cloud of the surface.

8. The scanning laser projector of claim 7 , wherein the drive circuit is configured to dynamically decrease the vertical scan rate of the at least one scanning mirror to provide increased vertical resolution in the 3-dimensional point cloud of the surface.

9. The scanning laser projector of claim 7 , wherein the drive circuit is configured to dynamically decrease the horizontal scan amplitude of the at least one scanning mirror to provide increased horizontal data density in the 3-dimensional point cloud of the surface.

10. The scanning laser projector of claim 1 , wherein the at least one source of laser light comprises an infrared laser, and wherein a pixel drive generator is configured to generate the depth mapping pulses with the infrared laser.

11. The scanning laser projector of claim 10 , wherein the at least one source of laser light additionally comprises a red laser, a blue laser, and a green laser and wherein a pixel drive generator is configured to generate projected image pixels using the red laser, the blue laser, and the green laser.

12. A method of projecting an image, comprising:
generating a laser beam;
reflecting the laser beam to generate a pattern of scan lines;
selectively generating projected image pixels with the laser beam during a first portion of the pattern of scan lines;
selectively generating depth mapping pulses with the laser beam during a second portion of the pattern of scan lines;
receiving reflections of the depth mapping pulses from a surface; and
generating a 3-dimensional point cloud of the surface based at least in part on the received reflections of the depth mapping pulses from the surface.

13. The method of claim 12 , wherein the first portion of the pattern of scan lines comprises scan lines moving in a first direction and wherein the second portion of the pattern of scan lines comprises scan lines moving in a second direction, where the first direction and the second direction are opposite directions.

14. The method of claim 12 , wherein the first portion of the pattern of scan lines and the second portion of the pattern of scan lines are horizontal scan lines interlaced together.

15. The method of claim 12 , wherein the first portion of the pattern of scan lines comprises scan lines during an active display period and wherein the second portion of the pattern of scan lines comprises scan lines during a vertical retrace period.

16. The method of claim 12 , wherein the first portion of the pattern of scan lines and the second portion of the pattern of scan lines comprises generating projected image pixels and depth mapping pulses in each scan line.

17. The method of claim 12 , wherein the generating the 3-dimensional point cloud of the surface comprises calculating a time of flight for return of the depth mapping pulses in the laser beam.

18. The method of claim 12 , further comprising dynamically adjusting at least one of a horizontal scan rate, a horizontal scan amplitude, a vertical scan rate, and a vertical scan amplitude of the pattern to modify characteristics of the 3-dimensional point cloud of the surface.

19. The method of claim 12 , further comprising dynamically decreasing a vertical scan rate of the pattern to provide increased vertical resolution in the 3-dimensional point cloud of the surface.

20. The method of claim 12 , further comprising dynamically decreasing a horizontal scan amplitude of the at least one scanning mirror to provide increased horizontal data density in the 3-dimensional point cloud of the surface.

21. The method of claim 12 , wherein the generating a laser beam comprises generating an infrared laser beam, and wherein the selectively generating the depth mapping pulses comprises generating the depth mapping pulses with the infrared laser beam.

22. The method of claim 21 , wherein the generating a laser beam further comprises generating a red laser beam, a blue laser beam, and a green laser beam and wherein the selectively generating the projected image pixels comprises generating the projected image pixels with the red laser beam, the blue laser beam, and the green laser beam.

Assignees

• Microvision Inc

Inventors

• Viswanathan P Selvan
• Honkanen Jari
• Wade Douglas R
• Xue Bin

Classifications

• G01B11/24

  for measuring contours or curvatures · CPC title

• G01B11/2518 Primary

  Projection by scanning of the object · CPC title

• G06T7/40

  Analysis of texture (depth or shape recovery from texture G06T7/529) · CPC title

• H04N9/3161

  using laser light sources (using laser beams scanning the display screen H04N9/3129) · CPC title

• G01S17/42

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