Active electro-optical identification

1. An optical identification tag, comprising:

a retroreflective layer;

a light modulator positioned over the retroreflective layer that is configured to temporally modulate light intensity; and

a control logic unit configured to modulate the light modulator according to a communication code in response to detection of an initialization code in light incident on the optical identification tag.

2. The optical identification tag of claim 1 , wherein the retroreflective layer comprises a plurality of micro-retroreflectors.

3. The optical identification tag of claim 1 , wherein the retroreflective layer comprises a plurality of glass beads.

4. The optical identification tag of claim 1 , wherein the light modulator comprises a liquid crystal shutter.

5. The optical identification tag of claim 1 , wherein the light modulator comprises a micro-electromechanical system actuator array.

6. The optical identification tag of claim 5 , wherein the actuator array is capable of utilizing a time-staggered shuttering sequence to produce a phased signal.

7. The optical identification tag of claim 1 , wherein the light modulator comprises a suspended particle device light shutter.

8. The optical identification tag of claim 1 , wherein the light modulator comprises an electrochromic light shutter.

9. The optical identification tag of claim 1 , wherein the light modulator comprises a nano-chromatic light shutter.

10. The optical identification tag of claim 1 , further comprising a power supply.

11. The optical identification tag of claim 10 , wherein the power supply comprises a battery.

12. The optical identification tag of claim 10 , wherein the power supply comprises a photocell.

13. The optical identification tag of claim 1 , wherein the communication code is communicated to the control logic unit via a data link from an external data source.

14. An optical identification tag, comprising: a light geometry modulator comprising a retroreflective array; and a control unit configured to modulate the light geometry modulator according to a communication code, wherein the control unit is configured to modulate the light geometry modulator by distorting a flatness of at least a portion of the retroreflective array.

15. The optical identification tag of claim 14 , wherein the retroreflective array comprises piezo electric plastic.

16. The optical identification tag of claim 14 , wherein the retroreflective array comprises a film of memory shape material.

17. The optical identification tag of claim 16 , wherein the memory shape material comprises a nickel tin alloy.

18. The optical identification tag of claim 14 , wherein the light geometry modulator further comprises a voice coil capable of dynamically flexing the retroreflective array.

19. The optical identification tag of claim 14 , further comprising a power supply.

20. The optical identification tag of claim 19 , wherein the power supply comprises a battery.

21. The optical identification tag of claim 19 , wherein the power supply comprises a photocell.

22. The optical identification tag of claim 14 , wherein the communication code is communicated to the control unit via a data link from an external data source.

23. An optical identification tag, comprising:

a retroreflective layer;

a light modulator positioned over the retroreflective layer, wherein the light modulator is configured to temporally modulate light and has a default non-reflective state;

a control logic unit; and

a photo-detector configured to detect a polling light signal;

wherein the control logic unit is configured to modulate the polling light signal incident upon the light modulator according to a communication code in response to a valid initialization code received by the photo-detector.

24. The optical identification tag of claim 23 , wherein the retroreflective layer comprises a plurality of micro-retroreflectors.

25. The optical identification tag of claim 23 , wherein the retroreflective layer comprises a plurality of glass beads.

26. The optical identification tag of claim 23 , wherein the light modulator comprises a liquid crystal shutter.

27. The optical identification tag of claim 23 , wherein the light modulator comprises a micro-electromechanical system actuator array.

28. The optical identification tag of claim 23 , wherein the light modulator comprises a suspended particle device light shutter.

29. The optical identification tag of claim 23 , wherein the light modulator comprises an electrochromic light shutter.

30. The optical identification tag of claim 23 , wherein the light modulator comprises a nano-chromatic light shutter.

31. The optical identification tag of claim 23 , further comprising a power supply.

32. The optical identification tag of claim 31 , wherein the power supply comprises a battery.

33. The optical identification tag of claim 31 , wherein the power supply comprises a photocell.

34. The optical identification tag of claim 23 , wherein the communication code is communicated to the control logic unit via a data link from an external data source.

35. The optical identification tag of claim 23 , wherein the initialization code comprises a friendly-fire designation and further wherein the light modulator is maintained in a non-reflective state unless responding to the friendly-fire designation.

36. A system, comprising: an optical identification tag comprising: a retroreflective layer; a light modulator positioned over the retroreflective layer, wherein the light modulator is configured to modulate light; a detector configured to detect illumination incident upon the optical identification tag; and a control logic unit configured to modulate the light modulator in response to detection of an initialization code within incident illumination by the detector; and an electro-optical transceiver comprising a light source configured to illuminate the optical identification tag and further comprising an optical sensor configured to receive a signal reflected from the optical identification tag.

37. The system of claim 36 , wherein the electro-optical transceiver further comprises a decoder for decoding the signal reflected from the optical identification tag.

38. The system of claim 36 , wherein the retroreflective layer comprises a plurality of micro-retroreflectors.

39. The system of claim 36 , wherein the light modulator comprises a liquid crystal shutter.

40. The system of claim 36 , wherein the light modulator comprises a micro-electromechanical system actuator array.

41. The system of claim 36 , wherein the optical identification tag further comprises a power supply.

42. The system of claim 41 , wherein the power supply comprises a battery.

43. The system of claim 41 , wherein the power supply comprises a photocell.

44. The system of claim 36 , wherein the communication code is communicated to the control unit via a data link from an external data source.

45. The system of claim 36 , wherein the initialization code comprises a friendly-fire designation and further wherein the light modulator is maintained in a non-reflective state unless responding to the friendly-fire designation.

46. A method, comprising:

illuminating an optical identification tag, wherein the optical identification tag comprises a retroreflective layer and a light modulator;

detecting an initialization code within the incident illumination;

modulating the incident illumination in response to detection of the initialization code;

receiving a signal reflected from the optical identification tag; and

decoding the reflected signal.

47. The method of claim 46 , wherein said illuminating an optical identification tag comprises illuminating the optical identification tag with a laser.

48. The method of claim 46 , wherein said decoding the reflected signal comprises decoding the reflected signal according to a code 39 specification.

49. The method of claim 46 , wherein said illuminating an optical identification tag comprises illuminating the optical identification tag with a friendly-fire designation.

50. The method of claim 49 , wherein said receiving a signal reflected from the optical identification tag comprises receiving a friendly force code reflected from the optical identification tag in response to the friendly-fire designation.

51. A method, comprising:

receiving a polling light from an electro-optical transceiver at a retroreflective surface;

retroreflecting the polling light back to the electro-optical transceiver; and

modulating the retroreflected polling light according to a communication code by distorting a flatness of at least a portion of the retroreflective surface.

52. The method of claim 51 , wherein said retroreflecting the polling light comprises retroreflecting the polling light using a plurality of micro-retroreflectors.

53. The method of claim 51 , wherein said retroreflecting the polling light comprises retroreflecting the polling light using a plurality of glass beads.

54. The method of claim 51 , wherein said modulating the retroreflected polling, light comprises modulating the polling light using a liquid crystal shutter.

55. The method of claim 51 , wherein said modulating the retroreflected polling light comprises modulating the polling light using a micro-electromechanical system actuator array.

56. The method of claim 51 , further comprising receiving the communication code via a data link from an external data source.

57. The method of claim 51 , further comprising detecting a valid initialization code, wherein said modulating the retroreflected polling light comprises modulating the retroreflected polling light in response to a detection of the valid initialization code.

58. The method of claim 51 , further comprising detecting a friendly-fire designation, wherein said modulating the retroreflected polling light comprises modulating the retroreflected polling light in response to a detection of the friendly-fire designation.