BIOMETRICS BASED ON LOCALLY CONSISTENT FEATURES

• US 20080232653A1
• Filed: 03/19/2008
• Published: 09/25/2008
• Est. Priority Date: 03/21/2007
• Status: Active Grant

• Current Assignee: HID Global Corporation (Assa Abloy AB)
• Original Assignee: Lumidigm Incorporated (Assa Abloy AB)
• Inventors: Rowe, Robert K.
• Granted Patent: US 8,285,010 B2
• Time in Patent Office: Days
• US Class Current: 382/124
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0062 Arrangements for scanning
• CPC Class Codes: A61B 5/1172 using fingerprinting
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: G06F 18/00 Pattern recognition
• CPC Class Codes: G06V 30/144 using a slot moved over the image; using discrete sensing elements at predetermined points; using automatic curve following means
• CPC Class Codes: G06V 40/1324 by using geometrical optics, e.g. using prisms G06V40/1312 takes precedence
• CPC Class Codes: G06V 40/1341 Sensing with light passing through the finger
• CPC Class Codes: G06V 40/14 Vascular patterns
• CPC Class Codes: G07C 9/37 using biometric data, e.g. fingerprints, iris scans or voice recognition

Abstract

Systems, devices, methods, and software are described for biometric sensors that permit a reduction in the size of the sensing area without significant reduction in biometric functionality of the sensor. A skin site of an individual is illuminated, and light scattered from the skin site is received. An image of a locally consistent feature of the skin site is formed from the received light. The locally consistent feature is analyzed to perform a biometric function.

Claims

1. A method of performing a biometric function, the method comprising:

illuminating a small-area purported skin site of an individual with illumination light;

receiving light scattered from the small-area purported skin site;

generating a local feature profile from the received light, wherein the local feature profile identifies a feature of the small-area purported skin site, the feature of the small-area purported skin site being of a type predetermined to exhibit substantial local consistency; and

analyzing the generated local feature profile to perform the biometric function,

wherein analyzing the generated local feature profile comprises comparing the generated local feature profile with a reference local feature profile,

wherein the reference local feature profile was generated from light scattered from a small-area reference skin site, and

wherein the small-area purported skin site is substantially different from the small-area reference skin site.

2. The method recited in claim 1, wherein the small-area purported skin site is in contact with a surface.

3. The method recited in claim 2, wherein the light is received substantially in a plane that includes the surface.

4. The method recited in claim 1, wherein the small-area purported skin site is a volar skin surface of the individual.

5. The method recited in claim 4, wherein the volar skin surface of the individual comprises a portion of a fingerprint of the individual.

6. The method recited in claim 1, wherein generating the local feature profile comprises:

forming an image from the received light;

generating spatially-distributed multispectral data from the image; and

processing the spatially-distributed multispectral data to generate the local feature profile.

7. The method recited in claim 1, wherein generating the local feature profile comprises:

forming an image from the received light;

generating an image-texture measure from the image; and

processing the generated image-texture measure to generate the local feature profile.

8. The method recited in claim 1 wherein:

the biometric function comprises an antispoofing function; and

analyzing the generated local feature profile comprises determining whether the small-area purported skin site comprises living tissue from the generated local feature profile.

9. The method recited in claim 1 wherein:

the biometric function comprises an identity function; and

analyzing the generated local feature profile comprises determining an identity of the individual from the generated local feature profile.

10. The method recited in claim 1 wherein:

the biometric function comprises a demographic function; and

analyzing the generated local feature profile comprises estimating a demographic characteristic of the individual from the generated local feature profile.

11. The method recited in claim 1 wherein:

the biometric function comprises an anthropometric function; and

analyzing the generated local feature profile comprises estimating an anthropometric characteristic of the individual from the generated local feature profile.

12. The method recited in claim 1 wherein:

receiving light scattered from the small-area purported skin site comprises receiving light scattered from the small-area purported skin site at an imaging detector.

13. The method recited in claim 12 wherein:

receiving light scattered from the small-area purported skin site comprises receiving light scattered from the small-area purported skin site at a surface plane of the imaging detector.

14. The method recited in claim 12 wherein receiving light scattered from the small-area purported skin site comprises:

receiving a pattern of light at a surface plane of a sensor platen;

translating the pattern of light from the surface plane of the platen to the imaging detector without substantial degradation or attenuation of the pattern of light, wherein the imaging detector is disposed outside the surface plane of the platen; and

receiving the translated pattern of light at the imaging detector.

15. The method recited in claim 1 wherein the illumination light is white light.

16. The method recited in claim 1 wherein illuminating the small-area purported skin site comprises illuminating the small-area purported skin site under a plurality of distinct optical conditions.

17. The method recited in claim 16 wherein illuminating the small-area purported skin site under the plurality of distinct optical conditions comprises illuminating the small-area purported skin site with light under a plurality of distinct polarization conditions.

18. The method recited in claim 16 wherein illuminating the small-area purported skin site under the plurality of distinct optical conditions comprises illuminating the small-area purported skin site with white light under a plurality of distinct wavelengths.

19. The method recited in claim 16 wherein generating the local feature profile from the received light comprises:

generating a plurality of images, each of the plurality of images corresponding to one of the distinct optical conditions; and

applying a compositing algorithm to the plurality of images.

20. The method recited in claim 16 wherein the reference local feature profile was further generated by:

generating a composite reference image from a plurality of images, each of the plurality of images corresponding to a previously imaged small-area reference skin site.

21. The method recited in claim 16 wherein illuminating the small-area purported skin site under the plurality of distinct optical conditions comprises illuminating the small-area purported skin site with light having a plurality of different wavelengths.

22. The method recited in claim 21 wherein generating the local feature profile comprises:

generating a plurality of images corresponding to the different wavelengths; and

performing a spatial moving-window analysis of at least a portion of the plurality of images.

23. The method recited in claim 22 wherein performing the spatial moving-window analysis comprises calculating a moving-window Fourier transform on the plurality of images.

24. The method recited in claim 22 wherein performing the spatial moving-window analysis comprises calculating a moving-window centrality measure and a moving-window variability measure of the plurality of images.

25. The method recited in claim 1 wherein receiving light scattered from the small-area purported skin site comprises receiving light scattered from the small-area purported skin site at a monochromatic imaging detector.

26. The method recited in claim 1 wherein receiving light scattered from the small-area purported skin site comprises receiving light scattered from the small-area purported skin site at a color imaging detector.

27. The method recited in claim 1 further comprising:

comparing spectral features of the received light with reference spectral features in performing the biometric function.

28. A biometric sensor comprising:

an illumination subsystem disposed to illuminate a small-area purported skin site of an individual with illumination light;

a detection subsystem disposed to receive light scattered from the small-area purported skin site; and

a computational unit interfaced with the detection subsystem and having;

instructions for generating a local feature profile from the received light, wherein the local feature profile identifies a feature of the small-area purported skin site, the feature of the small-area purported skin site being of a type predetermined to exhibit substantial local consistency; and

instructions for analyzing the generated local feature profile to perform a biometric function,

wherein analyzing the generated local feature profile comprises comparing the generated local feature profile with a reference local feature profile,

wherein the reference local feature profile was generated from light scattered from a small-area reference skin site, and

wherein the small-area purported skin site is substantially different from the reference small-area skin site.

29. The biometric sensor recited in claim 28, further comprising:

a surface adapted for contact with the small-area purported skin site of the individual.

30. The biometric sensor recited in claim 29, wherein:

the illumination subsystem is disposed to illuminate the small-area purported skin site when the small-area purported skin site is in contact with the surface.

31. The biometric sensor recited in claim 29, wherein:

the light is received substantially in a plane that includes the surface.

32. The biometric sensor recited in claim 28, wherein the small-area purported skin site is a volar skin surface of the individual.

33. The biometric sensor recited in claim 32, wherein the volar skin surface of the individual comprises a portion of a fingerprint of the individual.

34. The biometric sensor recited in claim 28, wherein the instructions for generating the local feature profile comprise:

forming an image from the received light;

generating spatially-distributed multispectral data from the image; and

processing the spatially-distributed multispectral data to generate the local feature profile.

35. The biometric sensor recited in claim 28, wherein the instructions for generating the local feature profile comprise:

forming an image from the received light;

generating an image-texture measure from the image; and

processing the generated image-texture measure to generate the local feature profile.

36. The biometric sensor recited in claim 28 wherein:

the biometric function comprises an antispoofing function; and

the instructions for generating the local feature profile comprise determining whether the small-area purported skin site comprises living tissue from the generated local feature profile.

37. The biometric sensor recited in claim 28 wherein:

the biometric function comprises an identity function; and

the instructions for generating the local feature profile comprise determining an identity of the individual from the generated local feature profile.

38. The biometric sensor recited in claim 28 wherein:

the biometric function comprises a demographic function; and

the instructions for generating the local feature profile comprise estimating a demographic characteristic of the individual from the generated local feature profile.

39. The biometric sensor recited in claim 28 wherein:

the biometric function comprises an anthropometric function; and

the instructions for generating the local feature profile comprise estimating an anthropometric characteristic of the individual from the generated local feature profile.

40. The biometric sensor recited in claim 28 further comprising an imaging detector, wherein:

the detection subsystem comprises the imaging detector and is configured to receive light scattered from the small-area purported skin site at the imaging detector.

41. The biometric sensor recited in claim 40 wherein:

the detection subsystem is configured to receive light scattered from the small-area purported skin site at a surface plane of the imaging detector.

42. The biometric sensor recited in claim 40 further comprising:

a sensor platen comprising a surface plane;

an imaging detector disposed outside the surface plane of the sensor platen; and

an optical arrangement configured to translate a pattern of light from the surface plane of the sensor platen to the imaging detector without substantial degradation or attenuation of the pattern of light,

wherein the detection subsystem comprises the imaging detector and is configured to receive the translated pattern of light at the imaging detector.

43. The biometric sensor recited in claim 40 wherein:

the imaging detector is a monochromatic imaging detector.

44. The biometric sensor recited in claim 40 wherein:

the imaging detector is a color imaging detector.

45. The biometric sensor recited in claim 28 wherein the illumination light is white light.

46. The biometric sensor recited in claim 28 wherein the illumination subsystem is disposed to illuminate the small-area purported skin site under a plurality of distinct optical conditions.

47. The biometric sensor recited in claim 46 wherein the plurality of distinct optical conditions comprises a plurality of distinct polarization conditions.

48. The biometric sensor recited in claim 46 wherein the plurality of distinct optical conditions comprises white light under a plurality of distinct wavelengths.

49. The biometric sensor recited in claim 46 wherein the instructions for generating the local feature profile from the received light comprise:

instructions for generating a plurality of images, each of the plurality of images corresponding to one of the distinct optical conditions; and

instructions for applying a compositing algorithm to the plurality of images.

50. The biometric sensor recited in claim 46 wherein the reference local feature profile was further generated by:

generating a composite reference image from a plurality of images, each of the plurality of images corresponding to a previously imaged small-area reference skin site.

51. The biometric sensor recited in claim 46 wherein the plurality of distinct optical conditions comprises light having a plurality of different wavelengths.

52. The biometric sensor recited in claim 51 wherein the instructions for generating the local feature profile comprise:

instructions for generating a plurality of images corresponding to the different wavelengths; and

instructions for performing a spatial moving-window analysis of at least a portion of the plurality of images.

53. The biometric sensor recited in claim 52 wherein the instructions for performing the spatial moving-window analysis comprise calculating a moving-window Fourier transform on the plurality of images.

54. The biometric sensor recited in claim 52 wherein the instructions for performing the spatial moving-window analysis comprise calculating a moving-window centrality measure and a moving-window variability measure of the plurality of images.

55. The biometric sensor recited in claim 28 wherein the computational unit further has instructions for comparing spectral features of the received light with reference spectral features in performing the biometric function.

56. The biometric sensor recited in claim 28 wherein an exposed surface of the sensor has an area less than 0.75 cm².

57. The biometric sensor recited in claim 28 wherein an exposed surface of the sensor has an area less than 0.5 cm².

58. The biometric sensor recited in claim 28 wherein an exposed surface of the sensor has an area less than 0.25 cm².

59. The biometric sensor recited in claim 28 wherein an exposed surface of the sensor has an area less than 0.1 cm².

60. The biometric sensor recited in claim 28 wherein an exposed surface of the sensor has an area less than 0.05 cm².

61. The biometric sensor recited in claim 28 wherein an exposed surface of the sensor has an area less than 0.01 cm².

62. The biometric sensor recited in claim 28 wherein the sensor is substantially a point sensor.