Recognizing commands with a depth sensor

1. A method for recognizing a command with a depth sensor, comprising:

monitoring a tangible reference at a reference distance from a depth sensor;

maintaining a virtual reference approximately on calibrated three dimensional coordinates derived from said reference distance, said virtual reference intermediary to said tangible reference and said depth sensor;

maintaining a touch space between said virtual reference and a touch boundary separated from said virtual reference by a touch distance; and

recognizing a command when a predetermined object enters said touch space.

2. The method of claim 1 , wherein maintaining a virtual reference approximately on calibrated three dimensional coordinates derived from said reference distance includes modifying said virtual reference as said tangible reference changes.

3. The method of claim 1 , wherein said predetermined object is a human hand.

4. The method of claim 3 , wherein recognizing a command when a predetermined object enters said touch space includes recognizing a contour of at least one fingertip of said human hand.

5. The method of claim 4 , wherein recognizing a command when a predetermined object enters said touch space includes estimating a skeletal structure of said human hand.

6. The method of claim 5 , further comprising merging data of said contour of said at least one fingertip and said skeletal structure.

7. The method of claim 1 , wherein said touch distance of said touch space is less than five millimeters.

8. The method of claim 1 , wherein recognizing a command when a predetermined object enters said touch space includes recognizing three dimensional gestures as commands.

9. The method of claim 8 , wherein forming an image on said tangible reference includes projecting an image onto said tangible reference.

10. The method of claim 1 , further comprising forming an image on said tangible reference.

11. A system for recognizing a command, comprising:

a depth sensor positioned to determine a distance that a surface is away from said depth sensor;

a processor in communication with said depth sensor; and

said processor is programmed to:

maintain a virtual reference intermediate to the depth sensor and surface based on continuous input received with said depth sensor;

establish a touch space adjacent said virtual reference; and

track a human hand moving into said touch space.

12. The system of claim 11 , wherein said processor is further programmed to localize finger tips of said human hand.

13. The system of claim 11 , wherein said processor is further programmed to estimate a skeletal structure of said human hand.

14. The system of claim 11 , further comprising a projector that forms an image on said tangible reference.

15. The system of claim 11 , wherein maintaining a virtual reference includes modifying said virtual reference as said tangible reference changes.

16. A computer program product, comprising:

a tangible computer readable storage medium, said computer readable storage medium comprising computer readable program code embodied therewith, said computer readable program code comprising:

computer readable program code to monitor a distance that a surface is away from a depth sensor; and

computer readable program code to maintain a touch space adjacent a virtual reference based on said surface; said touch space intermediary to said surface and said depth sensor; and

computer readable program code to recognize a command when a human hand enters said touch space.

17. The computer program product of claim 16 , further comprising computer readable program code to localize finger tips of said human hand and to estimate a skeletal structure of said human hand.

18. The computer program product of claim 16 , further comprising computer readable program code to form an image on said tangible reference.

19. The computer program product of claim 16 , further comprising computer readable program code to modifying said virtual reference as said tangible reference changes.

20. The computer program product of claim 16 , in which said distance that said surface is away from said depth sensor is less than five millimeters.