Multispectral biometric sensor

• US 7,147,153 B2
• Filed: 04/05/2004
• Issued: 12/12/2006
• Est. Priority Date: 04/04/2003
• Status: Active Grant

• Current Assignee: HID Global Corporation (Assa Abloy AB)
• Original Assignee: Lumidigm Incorporated (Assa Abloy AB)
• Inventors: Rowe, Robert K., Sidlauskas, David P.
• Primary Examiner(s): LE, UYEN CHAU N
• Application Number:
  US10/818,698
• Publication Number:
  US 20040240712A1
• Time in Patent Office: 981 Days
• Field of Search: 235/382, 235/380, 235/454, 902/3, 902/5, 705/18, 705/44, 382/115, 382/116, 382/124, 382/125, 382/191
• US Class Current: 235/382
• CPC Class Codes: A61B 5/1171 based on the shapes or appearances of their bodies or parts thereof
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/14558 by polarisation
• CPC Class Codes: B60K 28/06 responsive to incapacity of driver
• CPC Class Codes: B60R 25/252 Fingerprint recognition
• CPC Class Codes: B60W 2540/22 Psychological state; Stress level or workload
• CPC Class Codes: B60W 2540/221 Physiology, e.g. weight, heartbeat, health or special needs
• CPC Class Codes: B60W 2540/24 Drug level, e.g. alcohol
• 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

Abstract

Methods and systems are provided for biometric sensing. An illumination subsystem provides light at discrete wavelengths to a skin site of an individual. A detection subsystem receives light scattered from the skin site. A computational unit is interfaced with the detection system. The computational unit has instructions for deriving a spatially distributed multispectral image from the received light at the discrete wavelengths. The computational unit also has instructions for comparing the derived multispectral image with a database of multispectral images to identify the individual.

Claims

1. A sensor system comprising:

an illumination subsystem disposed to provide light at a plurality of discrete wavelengths to a skin site of an individual;

a detection subsystem disposed to receive light scattered from the skin site; and

a computational unit interfaced with the detection subsystem and having;

instructions for deriving a plurality of spatially distributed multispectral images from the received light at the plurality of discrete wavelengths, the plurality of spatially distributed multispectral images corresponding to different volumes of illuminated tissue of the individual; and

instructions for comparing subsurface characteristics extracted from the derived plurality of multispectral images with subsurface characteristics defined by a database of multispectral images to identify the individual.

2. The sensor system recited in claim 1 wherein the instructions for comparing the derived plurality of multispectral images with the database comprise instructions for searching the database for an entry identifying a multispectral image consistent with at least one of the derived plurality of multispectral images.

3. The sensor system recited in claim 1 wherein the instructions for comparing the derived plurality of multispectral images with the database comprise instructions for comparing the derived plurality of multispectral images with multispectral images at an entry of the database corresponding to a purported identity of the individual to verify the purported identity.

4. The sensor system recited in claim 1 wherein the illumination subsystem comprises:

a light source that provides the light at the plurality of discrete wavelengths; and

illumination optics to direct the light to the skin sites.

5. The sensor system recited in claim 4 wherein the illumination subsystem further comprises a scanner mechanism to scan the light in a specified pattern.

6. The sensor system recited in claim 4 wherein the light source comprises a plurality of quasimonochromatic light sources.

7. The sensor system recited in claim 6 wherein at least one of the quasimonochromatic light sources comprises an LED.

8. The sensor system recited in claim 6 wherein at least one of the quasimonochromatic light sources comprises a laser diode.

9. The sensor system recited in claim 4 wherein the illumination subsystem comprises:

a broadband light source; and

a filter disposed to filter light emitted from the broadband source.

10. The sensor system recited in claim 9 wherein the broadband light source comprises an incandescent bulb.

11. The sensor system recited in claim 10 wherein the broadband light source comprises a glowbar.

12. The sensor system recited in claim 10 wherein the filter comprises a continuously variable filter.

13. The sensor system recited in claim 10 wherein the detection subsystem comprises:

a light detector;

an optically dispersive element disposed to separate wavelength components of the received light; and

detection optics to direct the received light to the light detector.

14. The sensor system recited in claim 4 wherein the detection subsystem comprises:

a light detector; and

detection optics to direct the received light to the light detector.

15. The sensor system recited in claim 14 wherein:

the illumination subsystem further comprises a first polarizer disposed to encounter light emitted from the light source; and

the detection subsystem further comprises a second polarizer disposed to encounter the received light.

16. The sensor system recited in claim 15 wherein the first and the second polarizers comprise circular polarizers.

17. The sensor system recited in claim 15 wherein the first and the second polarizers comprise linear polarizers.

18. The sensor system recited in claim 17 wherein the first and the second polarizers are substantially crossed relative to each other.

19. The sensor system recited in claim 1 further comprising a platen disposed to contact the skin site.

20. The sensor system recited in claim 19 wherein the platen is adapted for the skin site to be swiped over a surface of the platen.

21. The sensor system recited in claim 20 further comprising a roller system over which the skin site may be rolled, wherein the instructions for deriving the spatially distributed multispectral image include instructions for building up the multispectral image from light received from different portions of the skin site as the skin site is rolled.

22. The sensor system recited in claim 1 wherein the computational unit further has:

instructions for deriving spectral-distribution characteristics from the received light; and

instructions for comparing the derived spectral-distribution characteristics with a database of spectral-distribution characteristics.

23. The sensor system recited in claim 22 wherein the computational unit further has instructions for determining an analyte concentration in tissue below a surface of the skin site from the derived spectral-distribution characteristics.

24. The sensor system recited in claim 23 wherein the analyte is selected from the group consisting of alcohol, glucose, hemoglobin, urea, and cholesterol.

25. The sensor system recited in claim 22 wherein the computational unit further has instructions for determining a liveness state of the tissue from the derived multispectral characteristics.

26. The sensor system recited in claim 1 wherein the plurality of discrete wavelengths are between about 400 nm and 2.5 μ

m.

27. The sensor system recited in claim 1 wherein the illumination subsystem comprises a plurality of illumination subsystems each disposed to provide light at a plurality of discrete wavelengths to the skin site.

28. The sensor system recited in claim 1 wherein the illumination subsystem is adapted to provide the plurality of discrete wavelengths substantially simultaneously and with an identifiable encoding.

29. The sensor system recited in claim 1 wherein the illumination subsystem is adapted to provide the plurality of discrete wavelengths sequentially.

30. A method for identifying an individual, the method comprising:

illuminating a skin site of the individual with light at a plurality of discrete wavelengths;

receiving light scattered from the skin site;

deriving a plurality of spatially distributed multispectral images from the received light at the plurality of discrete wavelengths, the plurality of spatially distributed multispectral images corresponding to different volumes of illuminated tissue of the individual; and

comparing subsurface characteristics extracted from the derived multispectral image with subsurface characteristics defined by a database of derived multispectral images to identify the individual.

31. The method recited in claim 30 wherein comparing the derived plurality of multispectral images with the database comprise searching the database for an entry identifying a multispectral image consistent with at least one of the derived plurality of multispectral images.

32. The method recited in claim 30 wherein comparing the derived plurality of multispectral images with the database comprises comparing the derived plurality of multispectral images with multispectral images at an entry of the database corresponding to a purported identity of the individual to verify the purported identity.

33. The method recited in claim 30 wherein illuminating the skin site comprises:

providing light at the plurality of discrete wavelengths; and

directing the light to the skin site.

34. The method recited in claim 33 further comprising scanning the light in a specified pattern.

35. The method recited in claim 33 wherein providing the light at the plurality of discrete wavelengths comprises generating the light as a plurality of quasimonochromatic beams.

36. The method recited in claim 33 wherein providing the light at the plurality of discrete wavelengths comprises:

generating a broadband beam of light; and

filtering the broadband beam.

37. The method recited in claim 36 wherein receiving the light comprises:

angularly separating separate wavelength components of the received light; and

directing the angularly separated wavelength components to a light detector.

38. The method recited in claim 33 wherein:

illuminating the skin site further comprises polarizing the provided light with a first polarization; and

receiving the light comprises polarizing the received light with a second polanriation.

39. The method recited in claim 38 wherein the first and second polarizations are substantially crossed relative to each other.

40. The method recited in claim 30 wherein the plurality of discrete wavelengths are between about 400 nm and 2.5 μ

m.

41. The method recited in claim 30 wherein illuminating the skin site with the light comprises illuminating the skin site with the plurality of discrete wavelengths substantially simultaneously and with an identifiable encoding.

42. The method recited in claim 30 wherein illuminating the skin site with the light comprises providing the plurality of discrete wavelengths sequentially.

43. The method recited in claim 42 wherein the plurality of discrete wavelengths are provided in a sequence that differs from a sequence of providing the plurality of discrete wavelengths on a prior measurement.

44. The method recited in claim 30 wherein the plurality of discrete wavelengths consists of a set of wavelengths that differs from a set of wavelengths used for a prior measurement.

45. The method recited in claim 30 wherein the skin site comprises a volar surface of a fingertip.

46. The method recited in claim 30 wherein the skin site comprises a volar surface of a hand.

47. The method recited in claim 30 further comprising:

deriving spectral-distribution characteristics from the received light; and

determining an analyte concentration in tissue below a surface of the skin site from the derived spectral-distribution characteristics.

48. The method recited in claim 47 wherein the analyte is selected from the group consisting of alcohol, glucose, hemoglobin, urea, and cholesterol.

49. The method recited in claim 30 further comprising:

deriving spectral-distribution characteristics from the received light; and

determining a liveness state from the derived multispectral characteristics.

50. The method recited in claim 30 further comprising:

deriving spectral-distribution characteristics from the received light; and

comparing the derived spectral-distribution characteristics with a database of spectral-distribution characteristics.