Interactive wireless tag location and identification system

• US 20060001543A1
• Filed: 07/01/2004
• Published: 01/05/2006
• Est. Priority Date: 07/01/2004
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Raskar, Ramesh, Dietz, Paul H., Beardsley, Paul A., Baar, Jeroen van
• Granted Patent: US 7,154,395 B2
• Time in Patent Office: Days
• US Class Current: 340/572.100
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/0728 the arrangement being an optical or sound-based communication interface
• CPC Class Codes: G06K 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions

Abstract

A wireless location and identification system includes a controller and a tag. The controller has a projector configured to generate a unique temporal sequence of light intensities for each pixel in an output image of the projector and a wireless transceiver configured to emit an output signal and receive an input signal. The tag includes a photo-sensor configured to sense the unique temporal sequence of light intensities of a particular pixel, a transducer configured to receive the output signal from the transceiver, and a means for modulating, according to the unique temporal sequence of light intensities, the input signal for the transceiver in response to receiving the output signal and sensing the unique temporal sequence of light intensities of the particular pixel to indicate a location of the tag to the controller.

Claims

1. A wireless location and identification system, comprising:

a controller, comprising;

a projector configured to generate a unique temporal sequence of light intensities for each pixel in an output image of the projector;

a wireless transceiver configured to emit an output signal and receive an input signal; and

a tag, comprising;

a photo-sensor configured to sense the unique temporal sequence of light intensities of a particular pixel;

a transducer configured to receive the output signal from the transceiver;

means for modulating, according to the unique temporal sequence of light intensities, the input signal for the transceiver in response to receiving the output signal and sensing the unique temporal sequence of light intensities of the particular pixel to indicate a location of the tag to the controller.

2. The system of claim 1, in which the tag further comprises:

a memory storing an identification of the tag; and

means for modulating, according to the identification, the input signal for the transceiver in response to receiving the output signal.

3. The system of claim 1, in which the tag further comprises:

a microcontroller connected to the transducer and the photo-sensor and a memory.

4. The system of claim 1, in which the tag further comprises an environment sensor connected to the microcontroller.

6. The system of claim 1, in which the tag is mounted in an object, and the controller is hand-held and mobile during operation.

7. The system of claim 1, in which the tag is mounted in an environment, and the controller is hand-held and mobile during operation.

8. The system of claim 1, in which the transducer and photo-sensor are approximate to an external physical surface.

9. The system of claim 1, in which the transducer is an antenna tuned to a predetermined radio frequency.

10. The system of claim 1, in which the tag acquires power parasitically.

11. The system of claim 1, in which the photo-sensor is driven in reverse bias to sense light and forward bias to emit light in response to sensing the unique temporal sequence of light intensities.

12. The system of claim 2, in which the memory stores the location.

13. The system of claim 1, in which the controller further comprises:

a processor connected to the projector, the transceiver, and a camera.

14. The system of claim 13, in which the projector is in a fixed physical relationship to the camera.

15. The system of claim 1, in which the controller further comprises a six degrees-of-freedom inertial sensor.

16. The system of claim 1, in which the controller further comprises:

a plurality of lasers pointers.

17. The system of claim 1, in which the controller further comprises:

a plurality of control buttons.

18. The system of claim 1, in which the controller further comprises:

means for determining a pose of the projector.

19. The system of claim 1, in which the photo-sensor is sensitive only to light at a selected frequency.

20. The system of claim 1, in which the sequence of light intensities for each pixel is in a form of a Gray code.

21. The system of claim 1, in which the system includes a plurality of tags, and a location of each tag is determined by the controller.

22. The system of claim 13, in which the location is determined from an input image acquired by the camera of the sequence of light intensities.

23. The system of claim 1, wherein the controller further comprises:

means for generating an output image in response to receiving the location of the tag.

24. The system of claim 23, in which the controller is hand-held and moving and the output image is stabilized with respect to the tag.

25. The system of claim 23, in which the output image includes a cursor that moves in correspondence to the moving of the controller.

26. The system of claim 25, in which the cursor selects items displayed in the output image.

27. The system of claim 23, in which the tag is mounted on a surface, and the controller further comprises:

a camera for acquiring an input image including the tag and the surface; and

means for incorporating a portion of the input image in the output image.

28. The system of claim 2, in which data stored in the memory is updated over time.

29. The system of claim 21, in which the plurality of tags are mounted on a surface, and means for determining a shape of the surface based on the locations of the tags.

30. The system of claim 21, in which the plurality of tags are mounted on a surface, and means for determining a deformation of the surface based on the locations of the tags.

31. The system of claim 1, in which the location is two-dimensional.

32. The system of claim 1, in which the location is three-dimensional.

33. The system of claim 1, in which the controller further comprises:

means for photo metrically compensating the light intensities,

34. The system of claim 1, in which the light intensities are infrared.

35. The system of claim 1, in which the tag includes a plurality of photo-sensors.

36. The system of claim 1, further comprising:

a plurality of light sources illuminating the tag, and the tag further comprises;

means for sensing any of the plurality of light sources.

37. A wireless location and identification method, comprising:

projecting, from a controller, a wireless output signal and a unique temporal sequence of light intensities for each pixel in an output image;

sensing in a tag, the wireless output signal;

sensing, in a tag, in response to sensing the wireless output signal, the unique temporal sequence of light intensities;

modulating, in the tag, according to the unique temporal sequence of light intensities, and input signal for the controller in response to receiving the output signal and sensing the unique temporal sequence of light intensities of the particular pixel to indicate a location of the tag to the controller.