IMAGE CONTRAST ENHANCEMENT IN DEPTH SENSOR

• US 20100304854A1
• Filed: 06/30/2010
• Published: 12/02/2010
• Est. Priority Date: 05/27/2009
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: McEldowney, Scott
• Granted Patent: US 8,054,290 B2
• Time in Patent Office: Days
• US Class Current: 463/30
• CPC Class Codes: A63F 2300/1087 comprising photodetecting means, e.g. a camera
• CPC Class Codes: A63F 2300/8029 Fighting without shooting
• CPC Class Codes: G06T 2207/10028 Range image; Depth image; 3D point clouds
• CPC Class Codes: G06T 2207/20224 Image subtraction
• CPC Class Codes: G06T 5/007 Dynamic range modification applied in cameras using an electronic image sensor H04N23/741, H04N23/743
• CPC Class Codes: G06T 5/90 Dynamic range modification of images or parts thereof
• CPC Class Codes: G06V 10/141 Control of illumination
• CPC Class Codes: G06V 10/145 Illumination specially adapted for pattern recognition, e.g. using gratings

Abstract

Embodiments related to the enhancement of contrast in an image pattern in a structured light depth sensor are disclosed. For example, one disclosed embodiment provides, in a structured light depth sensor system comprising a structured light depth sensor, a method comprising projecting a light pattern onto an object, detecting via an image sensor an image of the light pattern as reflected from the object, increasing a contrast of the light pattern relative to ambient light present in the image of the light pattern as reflected from the object to form a contrast-enhanced image of the light pattern as reflected from the object, and based upon a motion of the object as detected via the contrast-enhanced image of the light pattern, controlling an application that is providing output to a display.

Claims

1. In a structured light depth sensor system comprising a structured light depth sensor, a method comprising:

projecting a light pattern onto an object;

detecting via an image sensor an image of the light pattern as reflected from the object;

increasing a contrast of the light pattern relative to ambient light present in the image of the light pattern as reflected from the object to form a contrast-enhanced image of the light pattern as reflected from the object; and

based upon a motion of the object as detected via the contrast-enhanced image of the light pattern, controlling an application that is providing output to a display.

2. The method of claim 1, wherein projecting the light pattern comprises modulating an intensity of the light pattern as a function of time, and wherein increasing a contrast of the light pattern comprises subtracting a first image of the light pattern as reflected from the object at a first light pattern intensity with a second image of the light pattern as reflected from the object at a second light pattern intensity.

3. The method of claim 2, wherein modulating an intensity of the light pattern comprises turning the light pattern on and off.

4. The method of claim 1, wherein controlling the application comprises displaying a motion of an avatar on the display.

5. The method of claim 1, wherein the structured light depth sensor system comprises a computer gaming system.

6. The method of claim 1, wherein increasing a contrast of the light pattern comprises calculating a variance image from the image of the light pattern as reflected from the object.

7. The method of claim 6, wherein determining the variance image comprises, for each pixel, determining a variance value from an m×

n array of nearby pixels, wherein at least one of m and n has a value of at least 2.

8. The method of claim 6, wherein projecting the light pattern onto the object comprises projecting the light pattern via polarized light, and wherein increasing the contrast of the light pattern comprises filtering the light pattern reflected from the object via a polarization filter positioned optically between the object and the image sensor.

9. The method of claim 1, wherein projecting the light pattern onto the object comprises projecting the light pattern via polarized light, and wherein increasing the contrast of the light pattern comprises filtering the light pattern reflected from the object scene via a polarization filter positioned optically between the object and the image sensor.

10. The method of claim 9, wherein projecting the light pattern via polarized light comprises projecting the light pattern via a laser.

11. The method of claim 9, wherein projecting the light pattern via polarized light comprises producing the light pattern via an incoherent light source combined with another polarization filter.

12. An optical depth-sensing system, comprising:

an image source configured to project a light pattern onto an object;

an image sensor configured to capture an image of light reflected from the object;

a processor in operative communication with the image source, the display, and the image sensor; and

memory comprising instructions stored thereon that are executable by the processor to;

control projection of the light pattern onto the object;

receive from the image sensor an image of the light pattern as reflected from the object;

increase a contrast of the light pattern relative to ambient light in the image of the light pattern as reflected from the object to form a contrast-enhanced image of the light pattern as reflected from the object;

detect motion of the object via the contrast-enhanced image; and

in response to the motion, control an application that is providing an output to a display.

13. The apparatus of claim 12, wherein the instructions are executable to control projection of the light pattern onto the object by modulating an intensity of the light pattern as a function of time, and wherein the instructions are executable to increase the contrast of the light pattern by comparing a first image of the object at a first, higher light pattern intensity to a second image of the object at a second, lower light pattern intensity.

14. The apparatus of claim 12, wherein the instructions are executable to control the application by controlling a display of a motion of an avatar on the display.

15. The apparatus of claim 12, wherein the optical depth sensing system comprises a computer gaming system.

16. A computer gaming system, comprising:

an image source configured to project a light pattern onto a target;

an image sensor configured to capture an image of the light pattern reflected from the target;

a processor in operative communication with the image source and the image sensor; and

memory comprising instructions stored thereon that are executable by the processor to;

control projection of the light pattern onto the target;

receive from the image sensor an image of the light pattern as reflected from the target;

increase a contrast of the light pattern as reflected from the target to form a contrast-enhanced image of the light pattern as reflected from the target;

compare the contrast-enhanced image to a previously acquired contrast-enhanced image to detect motion of the target;

and

in response to detecting motion of the target, display motion of an avatar on a display.

17. The computer gaming system of claim 16, wherein the image source comprises a laser.

18. The computer gaming system of claim 16, further comprising a first polarization filter located between the target and the image sensor, and wherein image source comprises an incoherent light source and a second polarization filter configured to polarize light from the incoherent light source.

19. The computer gaming system of claim 16, wherein the instructions are further executable to modulate an intensity of the light pattern as a function of time, and to increase the contrast of the light pattern by comparing a first image of the target at a first, higher light pattern intensity to a second image of the target at a second, lower light pattern intensity.

20. The computer gaming system of claim 16, wherein the instructions are further executable to construct a variance image from the image of the light pattern detected via the image sensor, and to determine a distance value for each of one or more locations in target via the variance image.