PERSONAL AUTHENTICATION SYSTEM AND PERSONAL AUTHENTICATION METHOD

• US 20100074477A1
• Filed: 08/03/2007
• Published: 03/25/2010
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: OKI Electric Industry Company Limited
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: Fujii, Akihiro, Tohne, Toshio
• Granted Patent: US 8,170,295 B2
• Time in Patent Office: Days
• US Class Current: 382/117
• CPC Class Codes: G06F 21/32 using biometric data, e.g. fingerprints, iris scans or voiceprints
• CPC Class Codes: G06T 19/00 Manipulating 3D models or images for computer graphics
• CPC Class Codes: G06V 40/19 Sensors therefor

Abstract

A personal authentication system comprises an imaging section for capturing an image of a user'"'"'s eye including the iris; pupil/iris region extraction section for extracting a pupil region and an iris region from the captured image; a three-dimensional polar coordinate image creation section for estimating the three-dimensional center position of the eyeball based on the extracted pupil region and iris region and for creating a three-dimensional polar coordinate image by converting the iris region into three-dimensional coordinates with reference to the center position of the eyeball; and a three-dimensional polar coordinate image coding section for creating a three-dimensional polar coordinate image code formed by extracting and coding a characteristic of the created three-dimensional polar coordinate image. The personal authentication system can create iris information highly accurately representing characteristics of a user'"'"'s iris independent of the direction of line of sight of the user.

Claims

1. A personal authentication system comprising:

an imaging section for capturing an image of a user'"'"'s eye including the iris;

pupil/iris region extraction section for extracting a pupil region and an iris region from the captured image;

a three-dimensional polar coordinate image creation section for estimating the three-dimensional center position of the eyeball based on the extracted pupil region and iris region and for creating a three-dimensional polar coordinate image by converting the iris region into three-dimensional coordinates with reference to the center position of the eyeball; and

a three-dimensional polar coordinate image coding section for creating a three-dimensional polar coordinate image code formed by extracting and coding a characteristic of the created three-dimensional polar coordinate image.

2. The personal authentication system of claim 1, wherein the three-dimensional polar coordinate image creation section comprises:

a line of sight direction computation section for computing the direction of the line of sight of the user from a relationship of the central positions, and/or a relationship of the shapes, of respective regions of the extracted pupil region and the extracted iris region;

a three-dimensional model creating section for creating a three-dimensional model of the user'"'"'s eye using the computed line of sight, the pupil region and the iris region; and

a three-dimensional polar coordinate conversion section for determining from the created three-dimensional model a hypothetical projection plane for imaging the user with the direction of line of sight as the front, and for carrying out three-dimensional polar coordinate conversion of the iris region when the iris region is constructed so as to be facing parallel with respect to the determined hypothetical projection plane.

3. The personal authentication system of claim 2, wherein the line of sight direction computation section computes the direction of the line of sight from a misalignment in the central positions of respective regions of the extracted pupil region and the iris region, and from the distance relationship between the outer periphery of the pupil region and the outer periphery of the iris region.

4. The personal authentication system of claim 2, wherein the three-dimensional model creating section carries out normalization of the size of the three-dimensional model based on the size of the iris region.

5. The personal authentication system of claim 2, wherein in the three-dimensional polar coordinate image, each pixel of the iris region in the three-dimensional model is represented by the following two angles A and B,angle A being the angle formed between a preset reference line passing through the center of the eyeball and a projected straight line when a straight line in three-dimensions connecting the eyeball center to a pixel is projected onto a plane orthogonal to the axis of the line of sight;

and

2) angle B being the angle formed between a preset reference line passing through the center of the eyeball and a projected straight line when a straight line in three-dimensions connecting the eyeball center to a pixel is projected onto a vertical plane including the axis of the line of sight.

6. The personal authentication system of claim 1, further comprising a mask processing section, for mask processing such that noise including reflection portions within the extracted iris region is excluded from iris information and for creating a mask region.

7. The personal authentication system of claim 1, further comprising a mask processing section, for mask processing such that noise including reflection portions within the extracted iris region is excluded from iris information and for creating a mask region, wherein the three-dimensional polar coordinate image coding section partitions the three-dimensional polar coordinate image into a plurality of regions, and, for each of the plurality of regions, when the region includes mask region which is of a preset threshold value surface area or greater, the three-dimensional polar coordinate image coding section creates a mask code for the region.

8. The personal authentication system of claim 1, wherein the three-dimensional polar coordinate image coding section partitions the three-dimensional polar coordinate image into a plurality of regions, and, for each of the plurality of regions, when the region includes mask region which is less than a preset threshold value surface area or when the region does not include any mask region, the three-dimensional polar coordinate image coding section extracts a characteristic amount from the region, codes the extracted characteristic amount, and creates a three-dimensional polar coordinate image code.

9. The personal authentication system of claim 1, wherein the three-dimensional polar coordinate image coding section partitions the three-dimensional polar coordinate image into a plurality of regions, and, for each of the plurality of regions, codes a characteristic representing an output value obtained using a filter having directionality and periodicity on the region, and creates a three-dimensional polar coordinate image code.

10. The personal authentication system of claim 9, wherein the three-dimensional polar coordinate image coding section uses at least one of a directional filter and/or a two-dimensional Gabor filter as the filter having directionality and periodicity.

11. The personal authentication system of claim 8, wherein the three-dimensional polar coordinate image coding section uses at least one of two-dimensional Fourier transformation and/or two-dimensional wavelet transformation to extract the characteristic amount.

12. The personal authentication system of claim 1, wherein the three-dimensional polar coordinate image coding section comprises a pattern matching portion for partitioning the three-dimensional polar coordinate image into a plurality of regions and comparing each of the regions with the other regions using pattern matching, and the three-dimensional polar coordinate image coding section uses identification information representing each of the plurality of regions, and based on the matching results codes whether each of the regions is similar to any other region so as to create a three-dimensional polar coordinate code.

13. The personal authentication system of claim 1, further comprising a storage section for storing as registered biological information, the three-dimensional polar coordinate image code created during user registration.

14. The personal authentication system of claim 1, further comprising an authentification determination section for verifying the three-dimensional polar coordinate code created during user authentification against a three-dimensional polar coordinate code of registered biological information that has been registered in advance, and determining whether there is a match or a non-match.

15. A personal authentication method comprising:

extracting a pupil region and an iris region from an image of a user'"'"'s eye including the iris;

estimating the three-dimensional center position of the eyeball based on the extracted pupil region and iris region;

creating a three-dimensional polar coordinate image by converting the iris region into three-dimensional coordinates with reference to the center position of the eyeball; and

creating a three-dimensional polar coordinate image code formed by extracting and coding a characteristic of the created three-dimensional polar coordinate image.

16. The personal authentication method of claim 15, wherein the process of creating the three-dimensional polar coordinate image comprises:

computing the direction of the line of sight of the user from a relationship of the central positions or a relationship of the shapes of respective regions of the extracted pupil region and iris region;

creating a three-dimensional model of the user'"'"'s eye using the computed line of sight, the pupil region and the iris region; and

determining from the created three-dimensional model a hypothetical projection plane for imaging the user with the direction of line of sight as the front, and carrying out three-dimensional polar coordinate conversion of the iris region when the iris region is constructed so as to be facing parallel with respect to the determined hypothetical projection plane.

17. The personal authentication method of claim 16, wherein the direction of the line of sight is computed from a misalignment in the central positions of respective regions of the extracted pupil region and the iris region, and from the distance relationship between the outer periphery of the pupil region and the outer periphery of the iris region.

18. The personal authentication method of claim 16, wherein normalization of the size of the three-dimensional model is carried out based on the size of the iris region.

19. The personal authentication method of claim 16, wherein in the three-dimensional polar coordinate image, each pixel of the iris region in the three-dimensional model is represented by the following two angles A and B,angle A being the angle formed between a preset reference line passing through the center of the eyeball and a projected straight line when a straight line in three-dimensions connecting the eyeball center to a pixel is projected onto a plane orthogonal to the axis of the line of sight;

and

2) angle B being the angle formed between a preset reference line passing through the center of the eyeball and a projected straight line when a straight line in three-dimensions connecting the eyeball center to a pixel is projected onto a vertical plane including the axis of the line of sight.

20. The personal authentication method of claim 15, further comprising:

mask processing such that noise including reflection portions within the extracted iris region is excluded from iris information, creating a mask region.

21. The personal authentication method of claim 15, wherein mask processing is carried out such that noise including reflection portions of the extracted iris region is excluded from iris information and a mask region is created, and

the three-dimensional polar coordinate image is partitioned into a plurality of regions, and, for each of the plurality of regions, when the region includes mask region which is of a preset threshold value surface area or greater, a mask code is created for the region.

22. The personal authentication method of claim 15, wherein mask processing is carried out such that noise including reflection portions of the extracted iris region is excluded from iris information and a mask region is created, and

the three-dimensional polar coordinate image is partitioned into a plurality of regions, and, for each of the plurality of regions,

when the region includes mask region which is less than a preset threshold value surface area or when the region does not include any mask region, a characteristic amount is extracted from the region, the extracted characteristic amount is coded and a three-dimensional polar coordinate image code is created.

23. The personal authentication method of claim 15, wherein the method of creating the three-dimensional polar coordinate image codes is to partition the three-dimensional polar coordinate image into a plurality of regions, and, for each of the plurality of regions, to code a characteristic representing an output value obtained using a filter having directionality and periodicity on the region, creating the three-dimensional polar coordinate image code.

24. The personal authentication method of claim 23, wherein at least one of a directional filter and/or a two-dimensional Gabor filter is used as the filter having directionality and periodicity.

25. The personal authentication method of claim 22, wherein at least one of two-dimensional Fourier transformation and/or two-dimensional wavelet transformation is used to extract the characteristic amount.

26. The personal authentication method of claim 15, wherein the method for creating the three-dimensional polar coordinate image code comprises partitioning the three-dimensional polar coordinate image into a plurality of regions and comparing each of the regions with the other regions using pattern matching, and using identification information representing each of the plurality of regions, based on the matching results, to code whether each of the regions is similar to any other region so as to create a three-dimensional polar coordinate code.

27. The personal authentication method of claim 15, further comprising storing as registered biological information, the three-dimensional polar coordinate image code created during user registration.

28. The personal authentication method of claim 15, further comprising verifying the three-dimensional polar coordinate code created during user authentification against a three-dimensional polar coordinate code of registered biological information that has been registered in advance, and determining whether there is a match or a non-match.