Post processing of iris images to increase image quality
View Patent ↗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. Light illuminates the subjects' eyes and a high resolution camera captures images of the irises. The images of the irises are processed by a post processing module to improve their quality. In one approach, the point spread function of the image capture subsystem is estimated using glint reflections from the eye, and the estimated point spread function is used in deconvolution to increase the resolution of the iris images. The post processed iris images have sufficient resolution to be used for biometric identification.
1. A method for processing an image of an iris of an eye, comprising:
illuminating the eye with light;
steering a camera to the eye based on a reflection of the illuminating light from the eye;
the camera capturing an image of the iris of the eye; and
post processing, using an image post processing module, the captured iris image to produce a post processed iris image with a resolution of 200 microns or better and sufficient resolution for biometric identification.
2. The method of claim 1 wherein the step of post processing comprises applying deconvolution to the captured iris image.
3. The method of claim 2 wherein the step of applying deconvolution comprises:
estimating a point spread function from a glint reflection from the eye; and
applying deconvolution based on the estimated point spread function.
4. The method of claim 2 wherein the step of applying deconvolution comprises applying blind deconvolution to the captured iris image.
5. The method of claim 1 wherein the step of post processing comprises noise filtering the captured iris image.
6. The method of claim 1 wherein the step of post processing comprises applying a super-resolution algorithm to two or more captured iris images.
7. The method of claim 1 wherein the step of post processing comprises overlaying two or more captured iris images.
8. The method of claim 1 wherein the reflection from the eye is a retro-reflection from the eye.
9. The method of claim 1 wherein the reflection from the eye is a glint reflection from the eye.
10. The method of claim 1 wherein the step of steering the camera to the eye comprises using an adaptive optics loop based on the light reflected from the eye to steer the camera to the eye.
11. The method of claim 1 wherein the post processed iris image has a resolution that is at least 1.2 times better than that of the captured iris image.
12. The method of claim 1 wherein the camera can be steered to cover a capture volume of at least 1 cubic meter.
13. The method of claim 1 wherein the camera can capture iris images at a standoff of at least 1 m.
14. The method of claim 1 wherein the captured iris image has insufficient resolution for biometric identification.
15. A method for processing an image of an iris of an eye, comprising:
capturing an image of the iris of the eye;
estimating, using an image post processing module, a point spread function from a reflection from the eye; and
applying deconvolution, using the image post processing module, to the captured iris image based on the estimated point spread function to produce a post processed iris image a resolution of 200 microns or better and sufficient resolution for biometric identification.
16. The method of claim 15 further comprising noise filtering the captured iris image.
17. The method of claim 15 wherein the reflection from the eye is a retro-reflection from the eye.
18. The method of claim 15 wherein the reflection from the eye is a glint reflection from the eye.
19. The method of claim 15 further comprising:
illuminating the eye with light;
wherein the step of capturing an image of the iris comprises capturing the image of the iris illuminated by the illuminating light; and
wherein the step of estimating a point spread function from a reflection from the eye comprises estimating a point spread function from a reflection of the illuminating light from the eye.
20. The method of claim 15 further comprising:
illuminating the eye with light;
steering a camera to the eye based on a reflection of the illuminating light from the eye; and
wherein the step of estimating a point spread function from a reflection from the eye comprises estimating a point spread function from a reflection of the illuminating light from the eye.
21. The method of claim 15 wherein the post processed iris image has a resolution that is at least 1.2 times better than that of the captured iris image.
22. The method of claim 15 wherein the step of capturing an image of the iris occurs over a capture volume of at least 1 cubic meter.
23. The method of claim 15 wherein the step of capturing an image of the iris occurs at a standoff of at least 1 m.
24. The method of claim 15 wherein the captured iris image has insufficient resolution for biometric identification.
25. An iris imaging system for processing an image of an iris of an eye comprising:
an image capture subsystem comprising:
a light source for illuminating the eye with light;
a camera for capturing an image of the iris of the eye; and
a fine tracking system for steering a camera to the eye based on a reflection of the illuminating light from the eye; and
an image post processing module communicatively coupled to the image capture subsystem, for post processing the captured iris image to produce a post processed iris image with a resolution of 200 microns or better and sufficient resolution for biometric identification.
26. The iris imaging system of claim 25 wherein the image post processing module applies deconvolution to the captured iris image.
27. The iris imaging system of claim 25 wherein the reflection from the eye is a retro-reflection from the eye.
28. The iris imaging system of claim 25 wherein the reflection from the eye is a glint reflection from the eye.
29. The iris imaging system of claim 25 wherein fine tracking system includes an adaptive optics loop.
30. The iris imaging system of claim 25 wherein the captured iris image has insufficient resolution for biometric identification.
31. A iris imaging system for processing an image of an iris of an eye comprising:
an image capture subsystem for capturing an image of the iris of the eye; and
an image post processing module communicatively coupled to the image capture subsystem, for estimating a point spread function from a reflection from the eye and further for applying deconvolution to the captured iris image based on the estimated point spread function to produce a post processed iris image with a resolution of 200 microns or better and sufficient resolution for biometric identification.
32. The iris imaging system of claim 31 wherein the reflection from the eye is a retro-reflection from the eye.
33. The iris imaging system of claim 31 wherein the reflection from the eye is a glint reflection from the eye.
34. The iris imaging system of claim 31 wherein the light producing the reflection from the eye also illuminates the iris for capture by the image capture subsystem.
35. The iris imaging system of claim 31 wherein the light producing the reflection from the eye is also used to steer the image capture subsystem to the eye.
36. The iris imaging system of claim 31 wherein the captured iris image has insufficient resolution for biometric identification.
37. A method for processing an image of an iris of an eye, comprising:
illuminating the eye with light;
steering a camera to the eye based on a reflection of the illuminating light from the eye;
the camera capturing an image of the iris of the eye; and
post processing, using an image post processing module, the captured iris image to produce a post processed iris image with a resolution that is at least 1.2 times better than that of the captured iris image and with sufficient resolution for biometric identification.
38. The method of claim 37 wherein the step of post processing comprises applying deconvolution to the captured iris image.
39. The method of claim 38 wherein the step of applying deconvolution comprises:
estimating a point spread function from a glint reflection from the eye; and
applying deconvolution based on the estimated point spread function.
40. The method of claim 38 wherein the step of applying deconvolution comprises applying blind deconvolution to the captured iris image.
41. The method of claim 37 wherein the step of post processing comprises noise filtering the captured iris image.
42. The method of claim 37 wherein the step of post processing comprises applying a super-resolution algorithm to two or more captured iris images.
43. The method of claim 37 wherein the step of post processing comprises overlaying two or more captured iris images.
44. The method of claim 37 wherein the reflection from the eye is a retro-reflection from the eye.
45. The method of claim 37 wherein the reflection from the eye is a glint reflection from the eye.
46. The method of claim 37 wherein the step of steering the camera to the eye comprises using an adaptive optics loop based on the light reflected from the eye to steer the camera to the eye.
47. The method of claim 37 wherein the post processed iris image has a resolution of 200 microns or better.
48. The method of claim 37 wherein the camera can be steered to cover a capture volume of at least 1 cubic meter.
49. The method of claim 37 wherein the camera can capture iris images at a standoff of at least 1 m.
50. The method of claim 37 wherein the captured iris image has insufficient resolution for biometric identification.
51. A method for processing an image of an iris of an eye, comprising:
capturing an image of the iris of the eye;
estimating, using an image post processing module, a point spread function from a reflection from the eye; and
applying deconvolution, using the image post processing module, to the captured iris image based on the estimated point spread function to produce a post processed iris image with a resolution that is at least 1.2 times better than that of the captured iris image and with sufficient resolution for biometric identification.
52. The method of claim 51 further comprising noise filtering the captured iris image.
53. The method of claim 51 wherein the reflection from the eye is a retro-reflection from the eye.
54. The method of claim 51 wherein the reflection from the eye is a glint reflection from the eye.
55. The method of claim 51 further comprising:
illuminating the eye with light;
wherein the step of capturing an image of the iris comprises capturing the image of the iris illuminated by the illuminating light; and
wherein the step of estimating a point spread function from a reflection from the eye comprises estimating a point spread function from a reflection of the illuminating light from the eye.
56. The method of claim 51 further comprising:
illuminating the eye with light;
steering a camera to the eye based on a reflection of the illuminating light from the eye; and
wherein the step of estimating a point spread function from a reflection from the eye comprises estimating a point spread function from a reflection of the illuminating light from the eye.
57. The method of claim 51 wherein the post processed iris image has a resolution of 200 microns or better.
58. The method of claim 51 wherein the step of capturing an image of the iris occurs over a capture volume of at least 1 cubic meter.
59. The method of claim 51 wherein the step of capturing an image of the iris occurs at a standoff of at least 1 m.
60. The method of claim 51 wherein the captured iris image has insufficient resolution for biometric identification.
61. An iris imaging system for processing an image of an iris of an eye comprising:
an image capture subsystem comprising:
a light source for illuminating the eye with light;
a camera for capturing an image of the iris of the eye; and
a fine tracking system for steering a camera to the eye based on a reflection of the illuminating light from the eye; and
an image post processing module communicatively coupled to the image capture subsystem, for post processing the captured iris image to produce a post processed iris image with a resolution that is at least 1.2 times better than that of the captured iris image and with sufficient resolution for biometric identification.
62. The iris imaging system of claim 61 wherein the image post processing module applies deconvolution to the captured iris image.
63. The iris imaging system of claim 61 wherein the reflection from the eye is a retro-reflection from the eye.
64. The iris imaging system of claim 61 wherein the reflection from the eye is a glint reflection from the eye.
65. The iris imaging system of claim 61 wherein fine tracking system includes an adaptive optics loop.
66. The iris imaging system of claim 61 wherein the captured iris image has insufficient resolution for biometric identification.
67. A iris imaging system for processing an image of an iris of an eye comprising:
an image capture subsystem for capturing an image of the iris of the eye; and
an image post processing module communicatively coupled to the image capture subsystem, for estimating a point spread function from a reflection from the eye and further for applying deconvolution to the captured iris image based on the estimated point spread function to produce a post processed iris image with a resolution that is at least 1.2 times better than that of the captured iris image and with sufficient resolution for biometric identification.
68. The iris imaging system of claim 67 wherein the reflection from the eye is a retro-reflection from the eye.
69. The iris imaging system of claim 67 wherein the reflection from the eye is a glint reflection from the eye.
70. The iris imaging system of claim 67 wherein the light producing the reflection from the eye also illuminates the iris for capture by the image capture subsystem.
71. The iris imaging system of claim 67 wherein the light producing the reflection from the eye is also used to steer the image capture subsystem to the eye.
72. The iris imaging system of claim 67 wherein the captured iris image has insufficient resolution for biometric identification.
73. A method for processing an image of an iris of an eye, comprising:
illuminating the eye with light;
steering a camera to the eye based on a reflection of the illuminating light from the eye, wherein the camera can be steered to cover a capture volume of at least 1 cubic meter;
the camera capturing an image of the iris of the eye; and
post processing, using an image post processing module, the captured iris image to produce a post processed iris image with sufficient resolution for biometric identification.
74. The method of claim 73 wherein the step of post processing comprises applying deconvolution to the captured iris image.
75. The method of claim 74 wherein the step of applying deconvolution comprises:
estimating a point spread function from a glint reflection from the eye; and
applying deconvolution based on the estimated point spread function.
76. The method of claim 74 wherein the step of applying deconvolution comprises applying blind deconvolution to the captured iris image.
77. The method of claim 73 wherein the step of post processing comprises noise filtering the captured iris image.
78. The method of claim 73 wherein the step of post processing comprises applying a super-resolution algorithm to two or more captured iris images.
79. The method of claim 73 wherein the step of post processing comprises overlaying two or more captured iris images.
80. The method of claim 73 wherein the reflection from the eye is a retro-reflection from the eye.
81. The method of claim 73 wherein the reflection from the eye is a glint reflection from the eye.
82. The method of claim 73 wherein the step of steering the camera to the eye comprises using an adaptive optics loop based on the light reflected from the eye to steer the camera to the eye.
83. The method of claim 73 wherein the post processed iris image has a resolution that is at least 1.2 times better than that of the captured iris image.
84. The method of claim 73 wherein the post processed iris image has a resolution of 200 microns or better.
85. The method of claim 73 wherein the camera can capture iris images at a standoff of at least 1 m.
86. The method of claim 73 wherein the captured iris image has insufficient resolution for biometric identification.
87. A method for processing an image of an iris of an eye, comprising:
capturing an image of the iris of the eye, wherein capturing the image of the iris occurs over a capture volume of at least 1 cubic meter;
estimating, using an image post processing module, a point spread function from a reflection from the eye; and
applying deconvolution, using the image post processing module, to the captured iris image based on the estimated point spread function to produce a post processed iris image sufficient resolution for biometric identification.
88. The method of claim 87 further comprising noise filtering the captured iris image.
89. The method of claim 87 wherein the reflection from the eye is a retro-reflection from the eye.
90. The method of claim 87 wherein the reflection from the eye is a glint reflection from the eye.
91. The method of claim 87 further comprising:
illuminating the eye with light;
wherein the step of capturing an image of the iris comprises capturing the image of the iris illuminated by the illuminating light; and
wherein the step of estimating a point spread function from a reflection from the eye comprises estimating a point spread function from a reflection of the illuminating light from the eye.
92. The method of claim 87 further comprising:
illuminating the eye with light;
steering a camera to the eye based on a reflection of the illuminating light from the eye; and
wherein the step of estimating a point spread function from a reflection from the eye comprises estimating a point spread function from a reflection of the illuminating light from the eye.
93. The method of claim 87 wherein the post processed iris image has a resolution that is at least 1.2 times better than that of the captured iris image.
94. The method of claim 87 wherein the post processed iris image has a resolution of 200 microns or better.
95. The method of claim 87 wherein the step of capturing an image of the iris occurs at a standoff of at least 1 m.
96. The method of claim 87 wherein the captured iris image has insufficient resolution for biometric identification.
97. An iris imaging system for processing an image of an iris of an eye comprising:
an image capture subsystem comprising:
a light source for illuminating the eye with light;
a camera for capturing an image of the iris of the eye, wherein the camera can be steered to cover a capture volume of at least 1 cubic meter; and
a fine tracking system for steering a camera to the eye based on a reflection of the illuminating light from the eye; and
an image post processing module communicatively coupled to the image capture subsystem, for post processing the captured iris image to produce a post processed iris image with sufficient resolution for biometric identification.
98. The iris imaging system of claim 97 wherein the image post processing module applies deconvolution to the captured iris image.
99. The iris imaging system of claim 97 wherein the reflection from the eye is a retro-reflection from the eye.
100. The iris imaging system of claim 97 wherein the reflection from the eye is a glint reflection from the eye.
101. The iris imaging system of claim 97 wherein fine tracking system includes an adaptive optics loop.
102. The iris imaging system of claim 97 wherein the captured iris image has insufficient resolution for biometric identification.
103. A iris imaging system for processing an image of an iris of an eye comprising:
an image capture subsystem for capturing an image of the iris of the eye, wherein capturing the image of the iris occurs over a capture volume of at least 1 cubic meter; and
an image post processing module communicatively coupled to the image capture subsystem, for estimating a point spread function from a reflection from the eye and further for applying deconvolution to the captured iris image based on the estimated point spread function to produce a post processed iris image with sufficient resolution for biometric identification.
104. The iris imaging system of claim 103 wherein the reflection from the eye is a retro-reflection from the eye.
105. The iris imaging system of claim 103 wherein the reflection from the eye is a glint reflection from the eye.
106. The iris imaging system of claim 103 wherein the light producing the reflection from the eye also illuminates the iris for capture by the image capture subsystem.
107. The iris imaging system of claim 103 wherein the light producing the reflection from the eye is also used to steer the image capture subsystem to the eye.
108. The iris imaging system of claim 103 wherein the captured iris image has insufficient resolution for biometric identification.