Depth value measurement

Patent metadata

Field	Value
Publication number	US-9958259-B2
Application number	US-201614993350-A
Country	US
Kind code	B2
Filing date	Jan 12, 2016
Priority date	Jan 12, 2016
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

A depth value of an object is measured. The object is illuminated with a luminaire comprising at least three or more pixel-layers including a first pixel-layer, a second pixel-layer and a third pixel-layer, each pixel-layer including a rectangular array of pixels. One or more images are captured of the object illuminated by the pixel-layers of the luminaire. The depth value of a point on the surface of the object is determined based on the one or more captured images. The spaced-apart pixel-layers of the luminaire are grouped into at least a front group and a back group, and the front group is separated from the back group by a distance that is relatively large as compared to a distance by which the spaced-apart pixel-layers within any one group are separated.

First claim

What is claimed is:

1. A method for measuring a depth value of an object, the method comprising:
illuminating the object with a luminaire comprising at least three or more spaced-apart pixel-layers including a first pixel-layer, a second pixel-layer and a third pixel-layer, each pixel-layer including a rectangular array of pixels;
capturing one or more images of the object illuminated by the pixel-layers of the luminaire; and
determining the depth value of a point on the surface of the object based on the one or more captured images,
wherein the spaced-apart pixel-layers of the luminaire are grouped into at least a front group and a back group, and wherein the front group is separated from the back group by a distance that is relatively large as compared to a distance by which the spaced-apart pixel-layers within any one group are separated.

2. The method according to claim 1 , wherein there are at least as many pixel-layers in the front group as there are in the back group.

3. The method according to claim 1 , wherein the object is illuminated with one or more light patterns corresponding to binary coded patterns displayed on the pixel-layers.

4. The method according to claim 3 , wherein the captured images comprise images of light patterns from the luminaire as reflected by the surface of the object.

5. The method according to claim 3 , wherein at least one of the binary coded patterns is based on a Gray code.

6. The method according to claim 3 , wherein two of the binary coded patterns respectively displayed on two different pixel-layers are based on a long run-length Gray code.

7. The method according to claim 1 , wherein pixels in one of the pixel-layers have the same dot pitch and aspect ratio as pixels in one of the other pixel-layers.

8. The method according to claim 1 , wherein the depth value is determined at a resolution higher than the pixel resolution of each individual pixel-layer of the luminaire.

9. The method according to claim 1 , wherein multiple luminaries are positioned at different angular positions around an inspection station at which the object is positioned, and further comprising capturing one or more images of the object illuminated by the pixel-layers of the multiple luminaires and determining the depth value of a point on the surface of the object based on the one or more captured images.

10. The method according to claim 1 , wherein the images are captured by a single image capture device.

11. The method according to claim 1 , wherein the images are captured by multiple image capture devices positioned at different angular positions around an inspection station at which the object is positioned.

12. A method for measuring a depth value of an object, the method comprising:
a first illuminating step of illuminating the object with first and second pixel-layers of a luminaire, wherein the luminaire comprises three or more spaced-apart pixel-layers including the first and second pixel-layers and a third pixel-layer, each pixel-layer including a rectangular array of pixels;
capturing one or more images of the object illuminated with the first and second pixel-layers of the luminaire;
estimating a preliminary pixel correspondence between pixels of the third pixel-layer and pixels of the first and second pixel-layers based on the captured images;
determining dynamically a light pattern for illumination of the object by the second pixel-layer, based on the estimated preliminary pixel correspondence;
a second illuminating step of illuminating the object by the luminaire including displaying the dynamically determined light pattern on the second pixel-layer and displaying a predetermined light pattern on the third pixel-layer;
capturing images of the object simultaneously illuminated by the second and third pixel-layers of the luminaire;
refining the estimated preliminary pixel correspondence based on the captured images; and
determining the depth value of a point on the surface of the object using an illumination direction from a regression fitting based on the refined pixel correspondence among the three or more spaced-apart pixel-layers.

13. The method according to claim 12 , wherein the third pixel-layer is between the first pixel-layer and the second pixel-layer.

14. The method according to claim 12 , wherein the spaced-apart pixel-layers of the luminaire are grouped into at least a front group and a back group, and wherein the front group is separated from the back group by a distance that is relatively large as compared to a distance by which the spaced-apart pixel-layers within any one group are separated.

15. The method according to claim 14 , wherein there are at least as many pixel-layers in the front group as there are in the back group.

16. The method according to claim 12 , wherein the object is illuminated with one or more light patterns corresponding to binary coded patterns displayed on the pixel-layers.

17. The method according to claim 16 , wherein the captured images comprise images of light patterns from the luminaire as reflected by the surface of the object.

18. The method according to claim 16 , wherein in the first illuminating step, at least one of the binary coded patterns is based on a Gray code.

19. The method according to claim 16 , wherein in the second illuminating step, two of the binary coded patterns respectively displayed on two different pixel-layers are based on a long run-length Gray code.

20. The method according to claim 12 , wherein pixels in one of the pixel-layers have the same dot pitch and aspect ratio as pixels in one of the other pixel-layers.

21. The method according to claim 12 , wherein the depth value is determined at a resolution higher than the pixel resolution of each individual pixel-layer of the luminaire.

22. The method according to claim 12 , wherein multiple luminaries are positioned at different angular positions around an inspection station at which the object is positioned, and further comprising capturing one or more images of the object illuminated by the pixel-layers of the multiple luminaires and determining the depth value of a point on the surface of the object based on the one or more captured images.

23. The method according to claim 12 , wherein the images are captured by a single image capture device.

24. The method according to claim 12 , wherein the images are captured by multiple image capture devices positioned at different angular positions around an inspection station at which the object is positioned.

Assignees

• Canon Kk

Inventors

• Tin Siu-Kei
• Ye Jinwei

Classifications

• H04N23/90

  Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums · CPC title

• H04N23/56

  provided with illuminating means · CPC title

• G06T7/521 Primary

  from laser ranging, e.g. using interferometry; from the projection of structured light · CPC title

• G06T7/0051

  Physics · mapped topic

• G06K7/10732

  Light sources · CPC title