DEPTH CAMERA ILLUMINATOR WITH SUPERLUMINESCENT LIGHT-EMITTING DIODE

• US 20110310220A1
• Filed: 06/16/2010
• Published: 12/22/2011
• Est. Priority Date: 06/16/2010
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: McEldowney, Scott
• Granted Patent: US 8,670,029 B2
• Time in Patent Office: Days
• US Class Current: 348/42
• CPC Class Codes: G02B 5/1895 such optical elements having dioptric power
• CPC Class Codes: G03B 15/03 Combinations of cameras with lighting apparatus; Flash units
• CPC Class Codes: G03B 35/00 Stereoscopic photography
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: H04N 13/254 in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 25/705 Pixels for depth measurement, e.g. RGBZ

Abstract

A depth camera illuminator with a superluminescent light-emitting diode (SLED) in a motion tracking system. One or more SLEDs have a sufficient power, such as 75-200 milliwatts, to extend in a field of view in an area such as a room in a home. To correct for chromatic aberration which would otherwise exist due to the wider range of wavelengths which are emitted by an SLED compared to a laser, an achromatic diffractive optical element is used to disperse the light over the field of view. The achromatic diffractive optical element can have a stepped multi-level profile with three or more levels, or a continuous profile. Based on a tracked movement of a human target, an input is provided to an application in a motion tracking system, and the application performs a corresponding action such as updating a position of an on-screen avatar.

Claims

1. A 3-D depth camera system, comprising:

(a) an illuminator, the illuminator comprises;

(i) at least one superluminescent light-emitting diode;

(ii) a collimating lens which captures light from the at least one superluminescent light-emitting diode to provide a collimated light beam; and

(iii) a diffractive optical element which receives the collimated light beam, and creates a plurality of diffracted light beams which illuminate a field of view including a human target; and

(b) an image sensor which creates a depth image of the human target using light from the field of view.

2. The 3-D depth camera system of claim 1, wherein:

the diffractive optical element is achromatic.

3. The 3-D depth camera system of claim 1, further comprising:

at least one processor associated with the image sensor, the at least one processor tracks movement of the human target over time based on the depth information, and provides a corresponding control input to an application, and the application updates a display based on the control input.

4. The 3-D depth camera system of claim 1, wherein:

at least one superluminescent light-emitting diode outputs light at power level of at least 75 milliwatts.

5. The 3-D depth camera system of claim 1, wherein:

at least one superluminescent light-emitting diode outputs light at power level of at least about 100 to 200 milliwatts.

6. The 3-D depth camera system of claim 1, wherein:

the achromatic diffractive optical element comprises a plurality of stepped, multi-level diffractive structures on one side, each structure has three or more levels.

7. The 3-D depth camera system of claim 1, wherein:

the achromatic diffractive optical element has a continuous diffraction profile.

8. The 3-D depth camera system of claim 1, wherein:

the at least one superluminescent light-emitting diode operates in a modulated mode and outputs light at power level of at least about 200 milliwatts.

9. The 3-D depth camera system of claim 1, wherein:

the at least one superluminescent light-emitting diode operates in a continuous mode.

10. The 3-D depth camera system of claim 1, wherein:

the plurality of diffracted light beams have a nominally equal intensity.

11. The 3-D depth camera system of claim 1, wherein:

the achromatic diffractive optical element comprises an achromatic diffractive optical element which has a stepped, multi-level diffractive surface on one side, with three or more levels.

12. A 3-D depth camera system, comprising:

(a) an illuminator, the illuminator comprises;

(i) multiple superluminescent light-emitting diodes;

(ii) a respective microlens for each superluminescent light-emitting diode;

(iii) a collimating lens which captures light from the respective microlenses and provides a collimated light beam; and

(iv) an achromatic diffractive optical element which receives the collimated light beam, and creates a plurality of diffracted light beams which illuminate a field of view including a human target; and

(b) an image sensor which creates a depth image of the human target using light from the field of view.

13. The 3-D depth camera system of claim 12, wherein:

the achromatic diffractive optical element comprises a plurality of stepped, multi-level diffractive structures on one side, each structure has three or more levels.

14. The 3-D depth camera system of claim 12, wherein:

the achromatic diffractive optical element has a continuous diffraction profile.

15. The 3-D depth camera system of claim 12, wherein:

the multiple superluminescent light-emitting diode output light at a combined power level of at least 100 milliwatts.

16. A motion capture system, comprising:

a depth camera system, the depth camera system comprises at least one superluminescent light-emitting diode and an achromatic diffractive optical element which illuminates a field of view using light from the at least one superluminescent light-emitting diode, and at least one image sensor which senses reflected light from the field of view;

a display; and

one or more processors in communication with the depth camera system and the display, the one or more processors execute instructions to track movement of a body in the field of view over time, and to provide a signal to update the display based on the movement of the body over time.

17. The motion capture system of claim 16, wherein:

the display is updated by updating an avatar in a virtual world, and the avatar represents the body.

18. The motion capture system of claim 16, wherein:

at least one superluminescent light-emitting diode outputs light at power level of at least 75 milliwatts.

19. The motion capture system of claim 16, wherein:

the achromatic diffractive optical element comprises a plurality of stepped, multi-level diffractive structures on one side, each structure has three or more levels.

20. The motion capture system of claim 16, wherein:

at least one superluminescent light-emitting diode outputs light at power level of at least about 100 to 200 milliwatts.