Iris imaging using reflection from the eye

• US 7,428,320 B2
• Filed: 12/07/2005
• Issued: 09/23/2008
• Est. Priority Date: 12/07/2004
• Status: Active Grant

• Current Assignee: Tascent, Inc.
• Original Assignee: Aoptix Technologies Incorporated
• Inventors: Graves, J. Elon, Northcott, Malcolm J
• Primary Examiner(s): Chawan; Sheela C
• Application Number:
  US11/297,578
• Publication Number:
  US 20060140454A1
• Time in Patent Office: 1,021 Days
• Field of Search: 382/117, 382/118, 382/115, 382/291, 382/190, 382/124, 351/205, 351/206, 351/221, 351/207, 351/212, 351/219, 351/246, 351/220, 348/78, 348/335, 348/344, 348/346, 606/4, 359/210, 359/466, 356/71
• US Class Current: 382/117
• CPC Class Codes: A61B 3/1216 for diagnostics of the iris
• CPC Class Codes: A61B 5/1171 based on the shapes or appearances of their bodies or parts thereof
• CPC Class Codes: G06V 40/19 Sensors therefor

Abstract

A rapid iris acquisition, tracking, and imaging system can be used at longer standoff distances and over larger capture volumes, without the active cooperation of subjects. The captured iris images can be used for biometric identification. Light illuminates the subjects'"'"' eyes. Eye reflection from the eyes is used to steer a high resolution camera to the eyes in order to capture images of the irises.

Claims

1. An iris imaging system comprising an imaging subsystem, the imaging subsystem comprising:

a camera for capturing images of irises with sufficient resolution for biometric identification;

a light source for producing light to illuminate eyes; and

a fine tracking system comprising an adaptive optics loop including;

a deformable mirror for adjusting a wavefront of an eye reflection of the light illuminating the eyes;

a wavefront sensor for sensing the wavefront of the eye reflected light; and

a controller coupled between the deformable mirror and the wavefront sensor, for adjusting the deformable mirror based on the sensed wavefront to steer a field of view of the camera to the eyes,

wherein the fine tracking system can track irises to better than 0.5 cm accuracy.

2. The iris imaging system of claim 1 wherein the eye reflection comprises a retro-reflection from the eye.

3. The iris imaging system of claim 1 wherein the eye reflection comprises a glint reflection from the eye.

4. The iris imaging system of claim 1 wherein the imaging subsystem further comprises:

a polarization beamsplitter positioned between the deformable mirror and the wavefront sensor, wherein the light source produces polarized light and the polarization beamsplitter combines the polarized light into an optical path with the deformable mirror but reflects return light of the same polarization away from the wavefront sensor.

5. The iris imaging system of claim 1 wherein the deformable mirror is a deformable curvature mirror based on applying different voltages across different areas of a piezoelectric material.

6. The iris imaging system of claim 1 wherein the wavefront sensor is a wavefront curvature sensor based on defocused pupil images.

7. The iris imaging system of claim 1 wherein the fine tracking system has a speed to acquire and image at least ten irises per second.

8. The iris imaging system of claim 1 wherein the light source produces non- laser light.

9. The iris imaging system of claim 1 wherein the light source is an LED.

10. The iris imaging system of claim 1 wherein the light source produces light in a wavelength range that is greater than 750 nm.

11. The iris imaging system of claim 1 wherein the light source produces light in a wavelength range of 750 nm to 980 nm.

12. The iris imaging system of claim 1 wherein the light source produces light in a wavelength range that is greater than 850 nm.

13. The iris imaging system of claim 1 wherein the light source produces light in a wavelength range that is not visible to humans.

14. The iris imaging system of claim 1 wherein the camera is a monochromatic camera.

15. The iris imaging system of claim 1 wherein the camera captures images of irises with a resolution of 200 microns or better.

16. The iris imaging system of claim 1 wherein the camera captures images of irises with a resolution of 100 microns or better.

17. The iris imaging system of claim 1 wherein the camera captures images of irises with a resolution of 75 microns or better.

18. The iris imaging system of claim 1 further comprising:

off-axis light sources for illuminating the irises for image capture by the camera.

19. The iris imaging system of claim 1 wherein the imaging subsystem can cover a capture volume of at least 1 cubic meter.

20. The iris imaging system of claim 1 wherein the camera can capture iris images at a standoff of at least 5 m.

21. The iris imaging system of claim 1 wherein the camera can capture iris images at a standoff of at least 10 m.

22. The iris imaging system of claim 1 further comprising:

an acquisition subsystem for identifying an approximate location of subjects within a capture volume; and

a controller coupled to the acquisition subsystem and the imaging subsystem for coordinating the two subsystems.

23. The iris imaging system of claim 22 wherein the acquisition subsystem identifies the approximate location of subjects based on an eye reflection of illuminating light from the subjects'"'"' eyes.

24. The iris imaging system of claim 22 wherein the acquisition subsystem stares at the entire capture volume.

25. The iris imaging system of claim 22 wherein the acquisition subsystem scans across the capture volume.

26. The iris imaging system of claim 22 wherein the acquisition subsystem and the imaging subsystem are aligned along a common optical axis.

42. The iris imaging system of claim 10 wherein the camera captures images of irises with a resolution of 100 microns or better.

27. An iris imaging system comprising an imaging subsystem, the imaging subsystem comprising:

a camera for capturing images of irises with sufficient resolution for biometric identification;

a light source for producing light to illuminate eyes; and

a fine tracking system comprising an adaptive optics loop for steering a field of view of the camera to the eyes and also for focusing the camera on the irises, based on an eye reflection of the light illuminating the eyes, wherein the fine tracking system can track irises to better than 0.5 cm accuracy.

28. The iris imaging system of claim 27 wherein the eye reflection comprises a retro-reflection from the eye.

29. The iris imaging system of claim 27 wherein the eye reflection comprises a glint reflection from the eye.

30. The iris imaging system of claim 27 wherein the adaptive optics loop comprises a deformable mirror that is adjusted to steer the field of view of the camera to the eyes and also to focus the camera on the irises, based on a wavefront of the eye reflected light.

31. The iris imaging system of claim 30 wherein the deformable mirror is a deformable curvature mirror based on applying different voltages across different areas of a piezoelectric material.

32. The iris imaging system of claim 27 wherein the adaptive optics loop further comprises a wavefront curvature sensor based on defocused pupil images.

33. The iris imaging system of claim 27 wherein the fine tracking system has a speed to acquire and image at least ten irises per second.

34. The iris imaging system of claim 27 wherein the light source produces non-laser light.

35. The iris imaging system of claim 27 wherein the light source is an LED.

36. The iris imaging system of claim 27 wherein the light source produces light in a wavelength range that is greater than 750 nm.

37. The iris imaging system of claim 27 wherein the light source produces light in a wavelength range of 750 nm to 980 nm.

38. The iris imaging system of claim 27 wherein the light source produces light in a wavelength range that is greater than 850 nm.

39. The iris imaging system of claim 27 wherein the light source produces light in a wavelength range that is not visible to humans.

40. The iris imaging system of claim 27 wherein the camera is a monochromatic camera.

41. The iris imaging system of claim 27 wherein the camera captures images of irises with a resolution of 200 microns or better.

43. The iris imaging system of claim 27 wherein the camera captures images of irises with a resolution of 75 microns or better.

44. The iris imaging system of claim 27 further comprising:

off-axis light sources for illuminating the irises for image capture by the camera.

45. The iris imaging system of claim 27 wherein the imaging subsystem can cover a capture volume of at least 1 cubic meter.

46. The iris imaging system of claim 27 wherein the camera can capture iris images at a standoff of at least 5 m.

47. The iris imaging system of claim 27 wherein the camera can capture iris images at a standoff of at least 10 m.

48. The iris imaging system of claim 27 further comprising:

an acquisition subsystem for identifying an approximate location of subjects within a capture volume; and

a controller coupled to the acquisition subsystem and the imaging subsystem for coordinating the two subsystems.

49. The iris imaging system of claim 48 wherein the acquisition subsystem identifies the approximate location of subjects based on an eye reflection of illuminating light from the subjects'"'"' eyes.

50. The iris imaging system of claim 48 wherein the acquisition subsystem stares at the entire capture volume.

51. The iris imaging system of claim 48 wherein the acquisition subsystem scans across the capture volume.

52. The iris imaging system of claim 48 wherein the acquisition subsystem and the imaging subsystem are aligned along a common optical axis.

53. A method for imaging an iris of and eye, comprising:

illuminating the eye with light;

sensing a wavefront of an eye reflection from the eye;

steering a field of view of a camera to the eye and focusing the camera on an iris of the eye, based on the wavefront of the eye-reflected light; and

the camera capturing an image of the iris with at least 200 micron resolution for biometric identification.

54. The method of claim 53 wherein the eye reflection comprises a retroreflection from the eye.

55. The method of claim 53 weherein the eye reflection comprised a glint reflection from the eye.

56. The method of claim 53 wherein the stop of steering a field of view of the camera to the eye comprises using an adaptive optics loop based on the eye reflected light to steer the field of view of the camera to the eye.

57. The method of claim 53 wherein the step of steering a field of view of the camera to the eye is capable of steering the field of view of the camera to at least ten eyes per second.

58. The method of claim 53 wherein the step of illuminating the comprises illuminating the eye with light in a wavelength range that is greater than 750 nm.

59. The method of claim 53 wherein the step of illuminating the eye comprises illuminating the eye with light in a wavelength range that is not visible to humans.

60. The method of claim 53 wherein the field of view of the camera can be steered to cover a capture volume of a least 1 cubic meter.

61. The method of claim 53 wherein the camera can capture iris images at a standoff of at least 5m.

62. The method of claim 53 further comprising:

identifying an approximate location of subjects within a capture volume;

wherein the step of steering the field of view of the camera to the eye is based in part on the identified approximate locations.

63. The method of claim 62 wherein the step of identifying the approximate location of subjects is based on an eye reflection of illuminating light from the subjects'"'"' eyes.

64. The method of claim 62 wherein the step of identifying the approximate location of subjects comprises staring at the entire capture volume.

65. The method of claim 62 wherein the step of identifying the approximate location of subjects comprises scanning across the capture volume.