Projecting light patterns encoding correspondence information

• US 20070046924A1
• Filed: 08/30/2005
• Published: 03/01/2007
• Est. Priority Date: 08/30/2005
• Status: Abandoned Application

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Chang, Nelson
• Application Number:
  US11/214,594
• Publication Number:
  US 20070046924A1
• Time in Patent Office: Days
• US Class Current: 356/3.10
• CPC Class Codes: G01C 7/00 Tracing profiles by photogrammetry or videogrammetry G01C11/00

Abstract

In one aspect, a sequence of light patterns including cells having respective patterns of light symbols is projected onto a scene. The projected sequence of light patterns encodes pixels in a projection plane with respective temporal pixel codes corresponding to respective temporal sequences of light symbols coinciding with the locations of corresponding pixels. The projected sequence of light patterns uniquely encodes cells in the projection plane with respective temporal cell codes including respective sets of temporal pixel codes corresponding to respective sequences of light pattern cells. Respective temporal sequences of light patterns reflected from the scene are captured at regions of a capture plane. A correspondence mapping between the regions of the capture plane and corresponding cells in the projection plane is determined based at least in part on correspondence between the respective light pattern sequences captured at the capture plane regions and the temporal cell codes projected from the projection plane.

Claims

1. A method, comprising:

projecting onto a scene a sequence of light patterns comprising cells having respective patterns of light symbols, the projected sequence of light patterns encoding pixels in a projection plane with respective temporal pixel codes corresponding to respective temporal sequences of light symbols coinciding with the locations of corresponding pixels, and uniquely encoding cells in the projection plane with respective temporal cell codes comprising respective sets of temporal pixel codes corresponding to respective sequences of light pattern cells;

capturing at regions of a capture plane respective temporal sequences of light patterns reflected from the scene; and

determining a correspondence mapping between the regions of the capture plane and corresponding cells in the projection plane based at least in part on correspondence between the respective light pattern sequences captured at the capture plane regions and the temporal cell codes projected from the projection plane.

2. The method of claim 1, wherein the projected sequence of light patterns uniquely encodes non-overlapping cells in the projection plane with unique respective temporal cell codes.

3. The method of claim 1, wherein the projected sequence of light patterns uniquely encodes overlapping, spatially displaced cells in the projection plane with unique respective temporal cell codes.

4. The method of claim 1, wherein at least one of the light patterns comprises at least one pair of duplicate cells.

5. The method of claim 1, wherein each of the cells comprises a pattern of M rows and N columns of light symbols, M and N having integer values and at least one of M and N has a value of at least two.

6. The method of claim 5, wherein the light symbols have respective colors selected from a set of C colors, C having an integer value of at least two.

7. The method of claim 6, wherein the projecting comprise encoding each of the pixels in the projection plane with a respective temporal sequence of P light patterns, P having an integer value of at least two.

8. The method of claim 7, wherein C=8, P=2, M=2, and N=2.

9. The method of claim 7, wherein C=2, P=4, M=2, and N=2.

10. The method of claim 7, wherein C=3, P=3, M=2, and N=2.

11. The method of claim 1, wherein each light pattern consists of at least one cell.

12. The method of claim 1, wherein the projecting comprises projecting features demarcating the cells in the projection plane.

13. The method of claim 12, wherein the projecting comprises projecting a respective detectable boundary feature around each of the cells in the light patterns.

14. The method of claim 1, wherein groups of the projection plane pixels that are non-coincident with the projection plane cells are encoded with invalid temporal cell codes.

15. The method of claim 14, wherein adjacent ones of the projection plane cells are encoded with respective temporal cell codes having at least one temporal pixel code in common at adjacent pixel locations in the projection plane.

16. The method of claim 15, wherein the determining comprises labeling as invalid regions in the capture plane encoded with cell codes having at least one pair of duplicate temporal pixel codes.

17. The method of claim 1, wherein each of the temporal pixel codes is free of light symbols of same color.

18. The method of claim 1, wherein the determining comprises decoding the captured temporal sequences of light patterns.

19. The method of claim 18, wherein the decoding comprises assigning respective ones of the temporal pixel codes to pixels in the capture plane.

20. The method of claim 19, wherein the decoding comprises grouping capture plane pixels assigned same temporal pixel codes into spatial clusters of pixels.

21. The method of claim 20, wherein the decoding comprises labeling as valid groups of pixel clusters encoded with respective ones of the temporal cell codes.

22. The method of claim 21, wherein the decoding comprises labeling as indeterminate ones of the pixels in the capture plane encoded with temporal pixel codes designated as invalid.

23. The method of claim 21, wherein the decoding comprises mapping locations in valid pixel cluster groups in the capture plane to respective locations in corresponding cells in the projection plane.

24. The method of claim 23, wherein the mapping comprises matching temporal cell codes encoding the spatial cluster groups in the capture plane to temporal cell code entries in a table relating temporal cell codes with locations in projection plane cells.

25. The method of claim 23, wherein the decoding comprises mapping light symbol intersection points in valid pixel cluster groups in the capture plane to respective light symbol intersection points in corresponding cells in the projection plane.

26. The method of claim 1, further comprising:

during the projecting, capturing color information from the scene at locations in the capture plane corresponding to dark light symbols in the projected light patterns; and

storing the captured color information in a machine-readable medium.

27. The method of claim 1, wherein the projecting comprises projecting a repeating sequence of the light patterns.

28. The method of claim 27, wherein each of the repeating sequences comprises P light patterns, P having an integer value of at least two, and the determining comprises determining a respective correspondence mapping for each set of P successively projected light patterns.

29. The method of claim 28, wherein the light pattern sets are defined by respective sliding temporal windows temporally incremented with each successively projected light pattern.

30. A machine-readable medium storing machine-readable instructions for causing a machine to perform operations comprising:

projecting onto a scene a sequence of light patterns comprising cells having respective patterns of light symbols, the projected sequence of light patterns encoding pixels in a projection plane with respective temporal pixel codes corresponding to respective temporal sequences of light symbols coinciding with the locations of corresponding pixels, and uniquely encoding cells in the projection plane with respective temporal cell codes comprising respective sets of temporal pixel codes corresponding to respective sequences of light pattern cells;

capturing at regions of a capture plane respective temporal sequences of light patterns reflected from the scene; and

determining a correspondence mapping between the regions of the capture plane and corresponding cells in the projection plane based at least in part on correspondence between the respective light pattern sequences captured at the capture plane regions and the temporal cell codes projected from the projection plane.

31. An apparatus, comprising:

a projector;

an imaging device; and

a processing system operable to

control the projector to project onto a scene a sequence of light patterns comprising cells having respective patterns of light symbols, the projected sequence of light patterns encoding pixels in a projection plane with respective temporal pixel codes corresponding to respective temporal sequences of light symbols coinciding with the locations of corresponding pixels, and uniquely encoding cells in the projection plane with respective temporal cell codes comprising respective sets of temporal pixel codes corresponding to respective sequences of light pattern cells;

control the imaging device to capture at regions of a capture plane respective temporal sequences of light patterns reflected from the scene; and

determine a correspondence mapping between the regions of the capture plane and corresponding cells in the projection plane based at least in part on correspondence between the respective light pattern sequences captured at the capture plane regions and the temporal cell codes projected from the projection plane.

32. An apparatus, comprising:

means for projecting onto a scene a sequence of light patterns comprising cells having respective patterns of light symbols, the projected sequence of light patterns encoding pixels in a projection plane with respective temporal pixel codes corresponding to respective temporal sequences of light symbols coinciding with the locations of corresponding pixels, and uniquely encoding cells in the projection plane with respective temporal cell codes comprising respective sets of temporal pixel codes corresponding to respective sequences of light pattern cells;

means for capturing at regions of a capture plane respective temporal sequences of light patterns reflected from the scene; and

means for determining a correspondence mapping between the regions of the capture plane and corresponding cells in the projection plane based at least in part on correspondence between the respective light pattern sequences captured at the capture plane regions and the temporal cell codes projected from the projection plane.