Imager for constructing color and depth images

• US 8,723,118 B2
• Filed: 10/01/2009
• Issued: 05/13/2014
• Est. Priority Date: 10/01/2009
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: McEldowney, Scott, Giaimo, Edward
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): Malevic, Djura
• Application Number:
  US12/572,082
• Publication Number:
  US 20110079714A1
• Time in Patent Office: 1,685 Days
• Field of Search: 250/332, 250/226
• US Class Current: 250/332
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0205 Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
• CPC Class Codes: G01J 3/0224 using polarising or depolarising elements
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/0235 using means for replacing an element by another, for replacing a filter or a grating
• CPC Class Codes: H04N 13/254 in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths

Abstract

A dual-mode includes a light source configured to project a structured illumination from which visible light can be filtered. The dual-mode imager also includes a detector configured to capture both the structured illumination and visible light from the scene. A temporal or spatial filter is used to selectively block visible light from one or more portions of the detector while passing the structured illumination to the one or more portions of the detector.

Claims

1. A dual-mode imager for imaging a scene illuminated by visible light, the dual-mode imager comprising:

a light source configured to project onto the scene a structured illumination including infrared radiation from which a full spectrum of visible light is filterable;

a detector configured to capture both the structured illumination and visible light from the scene; and

a filter, between the scene and the detector, to selectively block the full spectrum of visible light from one or more portions of the detector while passing the structured illumination including the infrared radiation to the one or more portions of the detector.

2. The dual-mode imager of claim 1, where the filter includes a temporal filter configured to temporally alternate between blocking the full spectrum of visible light from the detector and passing visible light to the detector.

3. The dual-mode imager of claim 2, where the filter includes a rotating wheel filter including one or more portions configured to block the full spectrum of visible light and one or more portions configured to pass visible light.

4. The dual-mode imager of claim 3, where the rotating wheel filter is configured to block the full spectrum of visible light for approximately half of a rotation and pass visible light for approximately half of the rotation.

5. The dual-mode imager of claim 2, further comprising a controller to coordinate the temporal filter and the detector such that images captured by the detector while the temporal filter is blocking the full spectrum of visible light from the detector are sorted to construct a depth image, and such that images captured by the detector while the temporal filter is passing visible light to the detector are sorted to construct a color image.

6. The dual-mode imager of claim 5, where the temporal filter includes a polarizer and a photoelastic modulator to temporally alternate between blocking the full spectrum of visible light from the detector and passing visible light to the detector without moving parts.

7. The dual-mode imager of claim 1, where the filter includes a spatial filter configured to block the full spectrum of visible light from some portions of the detector while allowing visible light to pass to other portions of the detector.

8. The dual-mode imager of claim 7, where the detector includes a plurality of spatially alternating pixel groups, and where the spatial filter is configured to block the full spectrum of visible light from every other pixel group of the plurality of spatially alternating pixel groups.

9. The dual-mode imager of claim 8, where the plurality of spatially alternating pixel groups are spatially alternating rows of pixels.

10. The dual-mode imager of claim 7, where the spatial filter includes a polarizer, a wavelength sensitive color rotator, and a patterned polarizer having a polarization orientation that is space variant.

11. The dual-mode imager of claim 1, where the detector includes a complementary metal-oxide-semiconductor.

12. The dual-mode imager of claim 1, where the light source includes a laser having a near-infrared lasing wavelength.

13. The dual-mode imager of claim 12, where the light source includes a disperser configured to disperse a collimated beam from the laser among a range of projection angles to illuminate the scene with a plurality of spaced-apart light features having a near-infrared wavelength.

14. The dual-mode imager of claim 1, further comprising a depth analyzer configured to construct a depth image based on one or more images of the structured illumination captured by the detector.

15. A dual-mode imager for imaging a scene, the dual-mode imager comprising:

a near-infrared light source configured to project onto the scene a depth-imaging illumination having a near-infrared wavelength;

a complementary metal-oxide-semiconductor configured to capture near-infrared light and visible light from the scene; and

a rotating wheel filter optically intermediate the scene and the complementary metal-oxide-semiconductor, the rotating wheel filter including a first portion configured to block a full spectrum of visible light and pass near-infrared light and a second portion configured to pass visible light.

16. The dual-mode imager of claim 15, where the complementary metal-oxide-semiconductor captures two images during each rotation of the rotating wheel filter.

17. The dual-mode imager of claim 15, where the first portion is optically intermediate the scene and the complementary metal-oxide-semiconductor every other time the complementary metal-oxide-semiconductor captures an image.

18. The dual-mode imager of claim 15, further comprising a depth analyzer configured to construct a depth image based on one or more images captured by the complementary metal-oxide-semiconductor while the first portion is blocking the full spectrum of visible light from the complementary metal-oxide-semiconductor.

19. The dual-mode imager of claim 15, where the second portion is configured to block near-infrared light.

20. A method of constructing a color image and a depth image, the method comprising:

projecting onto a scene a structured illumination having a near-infrared wavelength;

temporally alternating between blocking a full spectrum of visible light from the scene to a detector and passing visible light from the scene to the detector;

while blocking the full spectrum of visible light from the scene, capturing the structured illumination with the detector;

while passing visible light from the scene, capturing visible light with the detector;

generating the depth image based on the structured illumination captured with the detector; and

generating the color image based on visible light captured with the detector.