Iris information acquisition apparatus and iris identification apparatus

• US 6,526,160 B1
• Filed: 07/09/1999
• Issued: 02/25/2003
• Est. Priority Date: 07/17/1998
• Status: Expired due to Term

• Current Assignee: Haruo Ito
• Original Assignee: Media Technology Corp. (TDK Corporation)
• Inventors: Ito, Haruo
• Primary Examiner(s): Werner, Brian
• Application Number:
  US09/350,142
• Time in Patent Office: 1,327 Days
• Field of Search: 382/117, 382/118, 382/124-127, 382/142, 382/312, 382/318, 382/319, 382/324, 356/71, 340/5.53, 340/5.83, 902/3, 902/6, 707/6, 713/186, 713/200, 250/208.6
• US Class Current: 382/117
• CPC Class Codes: A61B 3/1216 for diagnostics of the iris
• CPC Class Codes: G06V 40/18 Eye characteristics, e.g. of the iris
• CPC Class Codes: G06V 40/19 Sensors therefor
• CPC Class Codes: H04N 23/67 Focus control based on electronic image sensor signals
• CPC Class Codes: H04N 25/702 SSIS architectures characterised by non-identical, non-equidistant or non-planar pixel layout

Abstract

An iris recognition system capable of remarkably reducing time taking from an image pickup of an iris image to generation of an iris code and of simplifying the construction is implemented. A sensor 10 comprises a group of pixels arranged in polar coordinates. An iris image is controlled so that the iris image is correctly formed on the sensor 10, particularly, the center of the iris image matches. The inner and outer diameters of the iris are detected according to the iris image formed on the sensor 10, and the difference between the inner diameter and the outer diameter in the radial direction is detected. The number i of pixels of each ring in the case of division into the predetermined number of concentric ring bands is calculated according to the difference. A weighted mean processing part 13 performs a weighted mean operation according to the number i of pixels. A band-pass filter 15 performs a processing in the tangential and radial directions of feature extraction of the iris image of each ring band and generates the iris code with a binary format formed by a binary circuit 16.

Claims

1. An iris information sensor comprising:

an image pickup sensor having a group of photoelectric conversion pixels arranged in polar coordinates;

a focuser that focuses image light from an iris region of an eye on the image pickup sensor so that the center of an iris image formed on the sensor substantially matches with the pole of the polar coordinates of the sensor; and

a scanner that sequentially scans the photoelectric conversion pixels of the sensor to read out an iris image signal.

2. The iris information acquisition apparatus as defined in claim 1, wherein the image pickup sensor comprises a group of pixels arranged in concentric circles.

3. The iris information acquisition apparatus as defined in claim 1, wherein the image pickup sensor comprises a group of pixels arranged in a spiral shape extending in the radial direction.

4. An iris information acquisition apparatus for obtaining image information of an iris region, comprising:

an image pickup sensor having a group of photoelectric conversion pixels arranged in polar coordinates;

an image pickup optical focuser that focuses image light from the iris region on the image pickup sensor;

an optical axis operation controller that substantially matches the center of an iris image formed on the sensor with the pole of the polar coordinates of the sensor;

a region determiner that determines the iris region by acquiring the inner and outer diameters of the iris according to an iris image signal obtained by the sensor; and

a read scanner that scans the determined iris region in a predetermined sequence and obtains an output value corresponding to information of the iris region.

5. The iris information acquisition apparatus as defined in claim 4, wherein said read scanner scans the determined iris region at least in the tangential direction.

6. The iris information acquisition apparatus as defined in claim 4, wherein said read scanner that scans the determined iris region, scans the determined iris region in the tangential and radial directions at predetermined intervals.

7. The iris information acquisition apparatus as defined in claim 4, wherein said read scanner divides the determined iris region into predetermined concentric ring bands, determines the number of pixels in the radial direction of each ring band and reads the output value corresponding to information of each ring band in which a weighted mean is performed according to the number of pixels.

8. The iris information acquisition apparatus as defined in claim 4, wherein said region determiner determines the iris region according to an amplitude of a feature extraction signal, said feature extraction signal obtained by passing the image signal through a band-pass filter, said image signal obtained by scanning the image pickup sensor in the tangential direction.

9. The iris information acquisition apparatus as defined in claim 4, wherein said region determiner determines the iris region according to level variation in the image signal obtained by the scan in the radial direction of the image pickup sensor.

10. The iris information acquisition apparatus as defined in claim 4, wherein said optical axis operation controller calculates the direction and size of an error between the center of the iris image formed on the image pickup sensor and the pole of the polar coordinates of the sensor to control a matching of the center of the iris image with the pole of the polar coordinates of the sensor, by further passing the feature extraction signal through a low-pass filter, said feature extraction signal obtained by passing the image signal through the band-pass filter, said image signal obtained by scanning the image pickup sensor in the tangential direction.

11. The iris information acquisition apparatus as defined in claim 4, further comprising an illuminator that irradiates illumination light to the eye and a group of light receiving elements that receive reflected illumination light from the eye, said optical axis operation controller controlling a matching of the center of the iris image with the pole of the polar coordinates of the image pickup sensor according to an amount of receiving light of the group of light receiving elements.

12. The iris information acquisition apparatus as defined in claim 4, further comprising an iris code generator that generates an iris code according to the output value read by the read scanner.

13. The iris information acquisition apparatus as defined in claim 4, wherein said optical axis operation controller controls a matching of the center of the iris image formed on the image pickup sensor by moving a mirror placed in an optical path between the iris of the eye of a subject and the sensor with the pole of the polar coordinates of the sensor.

14. The iris information acquisition apparatus as defined in claim 4, wherein said optical axis operation controller controls a matching of the center of the iris image formed on the image pickup sensor by moving the sensor with the pole of the polar coordinates of the sensor.

15. The iris information acquisition apparatus as defined in claim 4, wherein said optical axis operation controller controls a matching of the center of the iris image formed on the image pickup sensor by a vertical angle variable prism placed in an optical path between the iris of the eye of a subject and the sensor with the pole of the polar coordinates of the sensor.

16. The iris information acquisition apparatus as defined in claim 4, wherein said optical axis operation controller controls a matching of the center of the iris image formed on the image pickup sensor by mutually translating a plurality of lenses placed in an optical path between the iris of the eye of a subject and the sensor with the pole of the polar coordinates of the sensor.

17. The iris information acquisition apparatus as defined in claim 4, wherein said image pickup sensor comprises a linear sensor in which pixels are arranged in the radial direction and a rotation driver that synchronously rotates the linear sensor around the pole of the polar coordinates, and a function equivalent to the group of the pixels of the polar coordinates is achieved by the rotation of the linear sensor through the rotation driver.

18. The iris information acquisition apparatus as defined in claim 4, wherein each pixel of the image pickup sensor comprises one of a MOS sensor and a CCD sensor.

19. The iris information acquisition apparatus as defined in claim 4, wherein each pixel of the image pickup sensor comprises a detector that detects edge information one of electrically and optically.

20. The iris information acquisition apparatus as defined in claim 4, wherein pixel density in the radial direction of each pixel of the image pickup sensor corresponds to the rate of stretching and shrinking of the iris.

21. The iris information acquisition apparatus as defined in claim 4, wherein the image pickup sensor comprises a group of pixels arranged in a spiral shape extending in the radial direction.

22. An iris information acquisition apparatus for obtaining image information of an iris region of the eye, comprising:

an image pickup sensor comprising a group of photoelectric conversion pixels arranged in polar coordinates;

an image pickup optical focuser that focuses image light from the iris region on the image pickup sensor;

an illuminator that irradiates illumination light to the eye having the iris;

an optical axis operation controller that substantially matches the center of an iris image formed on the sensor with the pole of the polar coordinates of the sensor;

a light adjustment controller that controls the inner diameter of the iris image formed on the sensor by irradiating visible light to the eye having the iris from the illuminator, adjusting an amount of the light and defining the pupil diameter; and

a read scanner that scans the sensor in a predetermined sequence and reads image information of the iris region.

23. The iris information acquisition apparatus as defined in claim 22, wherein said read scanner scans the determined iris region at least in the tangential direction.

24. The iris information acquisition apparatus as defined in claim 22, wherein said read scanner scans the determined iris region in the tangential and radial directions at predetermined intervals.

25. The iris information acquisition apparatus as defined in claim 22, wherein said image pickup optical focuser comprises a zoom lens, the zoom lens ensuring that the outer diameter of the iris image is formed on the image pickup sensor.

26. The iris information acquisition apparatus as defined in claim 22, wherein each pixel of the image pickup sensor has a light receiving region with an approximately rhombic shape having each diagonal in the radial and tangential directions of the polar coordinates.

27. The iris information acquisition apparatus as defined in claim 22, wherein each pixel of the image pickup sensor is also arranged in a region with an approximately rhombic shape surrounded by the light receiving regions with the approximately rhombic shape.

28. The iris information acquisition apparatus as defined in claim 22, further comprising an iris code generator that generates an iris code according to the output value read by the read scanner.

29. The iris information acquisition apparatus as defined in claim 28, wherein said iris code generator comprises a comparitor that compares a band-pass filter receiving the output value and output of the band-pass filter with a predetermined threshold value.

30. The iris information acquisition apparatus as defined in claim 28, wherein said iris code generator generates the iris code by comparing the output value of a plurality of continuous pixels with output of a target pixel.

31. The iris information acquisition apparatus as defined in claim 28, wherein information on the effective range of the iris region is added to the iris code.

32. The iris information acquisition apparatus as defined in claim 28, wherein information on resolution of the image pickup sensor is added to the iris code.

33. The iris information acquisition apparatus as defined in claim 28, wherein information on tilt of the eye is added to the iris code.

34. The iris information acquisition apparatus as defined in claim 28, wherein information on whether the iris code is the right eye or the left eye is added to the iris code.

35. The iris information acquisition apparatus as defined in claim 22, further comprising a group of light receiving elements that receive reflected light from the eye by said illuminator, said optical axis operation controller controls a matching of the center of the iris image with the pole of the polar coordinates of the image pickup sensor according to an amount of receiving light of the group of light receiving elements.

36. The iris information acquisition apparatus as defined in claim 22, wherein said optical axis operation controller calculates the direction and size of an error between the center of the iris image formed on the image pickup sensor and the pole of the polar coordinates of the sensor to control a matching of the center of the iris image with the pole of the polar coordinates of the sensor, by further passing a feature extraction signal through a low-pass filter, said feature extraction signal obtained by passing the image signal through the band-pass filter, said image signal obtained by scanning the image pickup sensor in the tangential direction.

37. The iris information acquisition apparatus as defined in claim 22, wherein said optical axis operation controller controls a matching of the center of the iris image formed on the image pickup sensor by moving a mirror placed in an optical path between the iris of the eye of a subject and the sensor with the pole of the polar coordinates of the sensor.

38. The iris information acquisition apparatus as defined in claim 22, wherein said optical axis operation controller controls a matching of the center of the iris image formed on the image pickup sensor by-moving the sensor with the pole of the polar coordinates of the sensor.

39. The iris information acquisition apparatus as defined in claim 22, wherein said optical axis operation controller controls a matching of the center of the iris image formed on the image pickup sensor by a vertical angle variable prism placed in an optical path between the iris of the eye of a subject and the sensor with the pole of the polar coordinates of the sensor.

40. The iris information acquisition apparatus as defined in claim 22, wherein said optical axis operation controller controls a matching of the center of the iris image formed on the image pickup sensor by mutually translating a plurality of lenses placed in an optical path between the iris of the eye of a subject and the sensor with the pole of the polar coordinates of the sensor.

41. The iris information acquisition apparatus as defined in claim 22, wherein said image pickup sensor comprises a linear sensor in which pixels are arranged in the radial direction and a rotation driver that synchronously rotates the linear sensor around the pole of the polar coordinates, and a function equivalent to the group of the pixels of the polar coordinates is achieved by the rotation of the linear sensor through the rotation driver.

42. An iris information acquisition apparatus as defined in claim 22, wherein each pixel of the image pickup sensor comprises one of a MOS sensor and a CCD sensor.

43. The iris information acquisition apparatus as defined in claim 22, wherein each pixel constructing the image pickup sensor comprises a detector that detects edge information one of electrically and optically.

44. The iris information acquisition apparatus as defined in claim 22, wherein pixel density in the radial direction of each pixel of the image pickup sensor corresponds to the rate of stretching and shrinking of the iris.

45. The iris information acquisition apparatus as defined in claim 22, wherein the image pickup sensor comprises a group of pixels arranged in a spiral shape extending in the radial direction.

46. An iris identification apparatus for acquiring an iris code representing information of an iris region of the eye and comparing and matching the acquired iris code with a previously registered iris code, comprising:

an image pickup sensor comprising a group of photoelectric conversion pixels arranged in polar coordinates;

an image pickup optical focuser that focuses image light from the iris region on the image pickup sensor;

an optical axis operation controller that substantially matches the center of an iris image formed on the sensor with the pole of the polar coordinates of the sensor;

a region determiner that determines the iris region by acquiring the inner and outer diameters of the iris according to an iris image signal obtained by the sensor;

a read scanner that divides the determined iris region into predetermined concentric ring bands and determines the number of pixels in the radial direction of each ring band and reads the output value corresponding to information of each ring band in which weighted mean is performed according to the number of pixels;

an iris code generator that generates the iris code according to the output value; and

a comparitor that matches the generated iris code with the previously registered iris code.

47. The iris identification apparatus as defined in claim 46, wherein said comparitor that matches the iris region including a region hidden by the eyelids.

48. The iris identification apparatus as defined in claim 46, further comprising a nonvolatile memory that stores the previously registered iris code, and one of an encoder that encodes and a cipher that ciphers the matched result in order to provide security.

49. The iris identification apparatus as defined in claim 48, further comprising an adjuster that adjusts the identification determination level used when matching the generated iris code with the previously registered iris code.

50. An iris identification apparatus that acquires information of an iris region of the eye and compares and matches the acquired information of the iris region with information of an iris region registered previously, comprising:

an image pickup sensor comprising a group of photoelectric conversion pixels arranged in polar coordinates;

an image pickup optical focuser that focuses image light from the iris region on the image pickup sensor;

an illuminator that radiates illumination light to the eye having the iris;

an optical axis operation controller that substantially matches the center of an iris image formed on the sensor with the pole of the polar coordinates of the sensor;

a light adjustment controller that controls the inner diameter of the iris image formed on the sensor by irradiating visible light to the eye having the iris from the illuminator, adjust an amount of the light and defines the pupil diameter;

a read scanner that scans the sensor in the tangential and radial directions and reads the information of the iris region; and

a matcher that matches the information of the iris region read by the read scanner with the information of the iris region registered previously through pattern matching.

51. The iris identification apparatus as defined in claim 50, wherein said image pickup optical focuser includes a zoom lens, the zoom lens ensuring that the outer diameter of the iris image is formed on the image pickup sensor.

52. The iris identification apparatus as defined in claim 50, wherein the matcher matches the iris region including a region hidden by the eyelids.

53. The iris identification apparatus as defined in claim 50, further comprising a nonvolatile memory that stores the previously registered iris code, and one of an encoder that encodes and a cipher that ciphers the matched result in order to provide security.

54. The iris identification apparatus as defined in claim 53, further comprising an adjuster that adjusts an identification determination level used when said matcher performs said matching.

55. An iris identification method for acquiring an iris code representing information of an iris region of the eye and comparing and matching the acquired iris code with a previously registered iris code, comprising:

using an image pickup sensor comprising a group of photoelectric conversion pixels arranged in polar coordinates;

focusing image light from the iris region on the image pickup sensor through an image pickup optical system;

substantially matching the center of an iris image formed on the sensor with the pole of the polar coordinates of the sensor through an optical axis operation controller;

determining the iris region by acquiring the inner and outer diameters of the iris according to an iris image signal obtained by the sensor;

dividing the determined iris region into predetermined concentric ring bands, determining the number of pixels in the radial direction of each ring band and reading the output value, corresponding to information of each ring band in which a weighted mean is calculated according to the number of pixels;

generating the iris code from the output value through an iris code generator; and

performing personal identification by matching the generated iris code with the previously registered iris code.

56. The iris identification method as defined in claim 55, wherein the iris region, including a region hidden by the eyelids, is matched.

57. The iris identification method as defined in claim 55, wherein the previously registered iris code is stored in a nonvolatile memory, and further comprising one of encoding and ciphering the matched result in order to provide security.

58. The iris identification method as defined in claim 57, wherein an identification determination level, when performing personal identification, is adjustable.

59. An iris identification method for acquiring information of an iris region of the eye and comparing and matching the acquired information of the iris region with information of an iris region registered previously, comprising:

using an image pickup sensor comprising a group of photoelectric conversion pixels arranged in polar coordinates;

focusing image light from the iris region on the image pickup sensor through an image pickup optical system;

irradiating illumination light to the eye having the iris through an illuminator;

substantially matching the center of an iris image formed on the sensor with the pole of the polar coordinates of the sensor through an optical axis operation controller;

controlling the inner diameter of the iris image formed on the sensor by irradiating visible light to the eye having the iris from the illuminator, adjusting an amount of the light and defining the pupil diameter;

scanning the sensor in the tangential and radial directions and reading the information of the iris region through a read scanner; and

performing personal identification by matching the information of the iris region read by the read scanner with the information of the iris region registered previously through pattern matching.

60. The iris identification method as defined in claim 59, wherein said image pickup optical system includes a zoom lens, the zoom lens ensuring that the outer diameter of the iris image is formed on the image pickup sensor.

61. The iris identification method as defined in claim 59, wherein the iris region, including a region, hidden by the eyelids, is matched.

62. The iris identification method as defined in claim 59, wherein the previously registered iris code is stored in a nonvolatile memory, and further comprising one of encoding and ciphering the matched result in order to provide security.

63. The iris identification method as defined in claim 62, wherein an identification determination level, when performing personal identification, is adjustable.

64. An iris information sensing method using an iris image pickup sensor having a group of photoelectric conversion pixels arranged in polar coordinates, the method comprising:

focusing image light from an iris of an eye on the image pickup sensor so that the center of an iris image formed on the sensor substantially matches with the pole of the polar coordinates of the sensor; and

sequentially scanning the photoelectric conversion pixels of the sensor to read out an iris image signal.