Enhancing stereo depth measurements with projected texture

• US 7,970,177 B2
• Filed: 03/22/2007
• Issued: 06/28/2011
• Est. Priority Date: 03/23/2006
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Tyzx, Inc. (Intel Corporation)
• Inventors: Woodfill, John Iselin, St. Hilaire, Pierre, Gordon, Gaile Gibson, Buck, Ronald J., Clohset, Steve
• Primary Examiner(s): Strege; John B
• Application Number:
  US11/728,202
• Publication Number:
  US 20070263903A1
• Time in Patent Office: 1,559 Days
• Field of Search: 382/106, 382/154, 356/3, 356/486, 356/493, 356/603, 356/604, 356/605, 356/614
• US Class Current: 382/106
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50
• CPC Class Codes: G01B 11/2545 with one projection direction and several detection directions, e.g. stereo
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light
• CPC Class Codes: G06T 7/593 from stereo images

Abstract

A system for distance calculation is disclosed. The system includes an illuminator unit, one or more camera units, and a distance processor. The illuminator unit illuminates a scene in a target area using a textured pattern creator and wherein the textured pattern creator includes a diffractive optical element. The one or more camera units captures two or more images of the target area from two or more physical locations. A textured pattern illumination is visible in each of the two or more images of the target area. The images are used to calculate distances to one or more points in the scene in the target area.

Claims

1. A system for calculating distance comprising:

an illuminator unit, wherein the illuminator unit illuminates a scene in a target area using a textured pattern creator and wherein the textured pattern creator includes a diffractive optical element, wherein the diffractive optical element comprises a substrate encoding a desired projection pattern as an amplitude profile or a phase profile, wherein the illuminator unit illuminates the scene using the textured pattern creator to generate a desired projection pattern as a textured pattern illumination, and wherein the desired projection pattern comprises a random or an irregular pattern;

one or more camera units, wherein the one or more camera units captures two or more images of the target area from two or more physical locations; and

a distance processor, wherein the textured pattern illumination visible in each of the two or more images of the target area is used to calculate distances to one or more points in the scene in the target area.

2. A system as in claim 1, wherein the illuminator unit includes an illumination source.

3. A system as in claim 2, wherein the illumination source is one of the following:

a laser, a diode laser, an infrared laser, a laser capable of being pulsed, a light emitting diode, or a flash lamp.

4. A system as in claim 1, wherein the textured pattern creator can be designed with a definable field of view.

5. A system as in claim 1, wherein the textured pattern creator can create a pattern of illumination that is in focus at substantially all distances.

6. A system as in claim 1, wherein the textured pattern creator can create a pattern of illumination that can be pulsed on.

7. A system as in claim 1, wherein one or more scene features visible in each of the two or more images of the target area is used to calculate distances to one or more points in the scene in the target area.

8. A system as in claim 1, wherein the camera unit includes a bandpass filter.

9. A system as in claim 1, wherein the illuminator unit is located in close proximity to the camera unit.

10. A system as in claim 1, wherein the illuminator unit is not located in close proximity to the camera unit.

11. A system as in claim 1, wherein the illuminator unit is one of a plurality of illuminator units, wherein the textured pattern creator of each of the plurality of illuminator units illuminates the scene, and wherein the scene includes a region illuminated by one or more of the plurality of illuminator units.

12. A system as in claim 1, wherein the illuminator unit moves.

13. A system as in claim 1, wherein the distance processor comprises one of the following:

a pipelined hardware processor, a software processor, or a partially hardware and partially software processor.

14. A system as in claim 1, wherein the distance processor uses the two or more images and information about the two or more physical locations from which the two or more images are captured to calculate distances to the one or more points in the scene in the target area.

15. A system as in claim 1, further comprising a synchronizer unit, wherein the synchronizer unit synchronizes the illuminator unit and the camera unit so that the two or more images captured by the camera unit are appropriately illuminated.

16. A method for calculating distances comprising:

illuminating a scene in a target area using a textured pattern creator, wherein the textured pattern creator includes a diffractive optical element, wherein the diffractive optical element comprises a substrate encoding a desired projection pattern as an amplitude profile or a phase profile, wherein the illuminator unit illuminates the scene using the textured pattern creator to generate a desired projection pattern as a textured pattern illumination, and wherein the desired projection pattern comprises a random or an irregular pattern;

capturing two or more images of the target area from two or more physical locations; and

calculating distances to the one or more points in the scene in the target area using the textured pattern illumination visible in each of the two or more images of the target area.

17. A method as in claim 16, wherein illuminating includes using an illumination source.

18. A method as in claim 17, wherein the illumination source is one of the following:

a laser, a diode laser, an infrared laser, a laser capable of being pulsed, a light emitting diode, or a flash lamp.

19. A method as in claim 18, wherein the illuminating includes using a textured pattern creator.

20. A method as in claim 19, wherein the textured pattern creator comprises a diffractive optical element.

21. A method as in claim 19, wherein the textured pattern creator can be designed with a definable field of view.

22. A method as in claim 19, wherein the textured pattern creator can create a pattern of illumination that is in focus at substantially all distances.

23. A method as in claim 19, wherein the textured pattern creator can create a pattern of illumination that can be pulsed on.

24. A method as in claim 19, wherein the textured pattern creator can create a pattern of illumination that can be pulsed on with sufficient intensity to enable the camera unit to capture an image of the textured pattern.

25. A method as in claim 16, wherein illuminating includes using a filter.

26. A method as in claim 16, wherein illuminating includes using a filter enabling both a textured pattern illuminating image and a non-texture pattern illuminating image to be captured.

27. A method as in claim 17, wherein the illumination source is in close proximity to the camera unit.

28. A method as in claim 17, wherein the illumination source is not in close proximity to the camera unit.

29. A method as in claim 17, wherein the illumination source is one of a plurality of illumination sources located in a plurality of locations, wherein the textured pattern creator of each of the plurality of illuminator units illuminates the scene, and wherein the scene includes a region illuminated by one or more of the plurality of illuminator units.

30. A method as in claim 16, wherein calculating distance uses one of the following:

a pipelined hardware processor, a software processor, or a partially hardware and partially software processor.

31. A method as in claim 16, wherein calculating distance uses the two or more images and position information from which the two or more images are captured to calculate distances to the one or more points in the scene in the target area.

32. A method as in claim 16, further comprising synchronizing illuminating the one more points in the scene in the target area and the capturing of two or more images so that the two or more images captured are appropriately illuminated.