Biometric authentication using the eye

1. Apparatus for authenticating a subject, comprising:

an image projection device to generate and project an image of a pattern, made up of plural discrete points, onto at least a part of the cornea of an eye of the subject;

an image capture device to capture an image of the pattern of plural discrete points, after reflection in at least a part of the cornea of an eye of the subject; and,

a computer processor to extract a first data set defining the locations of the discrete points in the captured image, and to compare the first data set against a second data set defining locations of corresponding points in a reference set according to:

M

=

∑

n

∈

N

⁢

⁢

w

n

⁢



A

n

-

B

n



p

∑

n

∈

N

⁢

⁢

w

n

where M is a similarity score between the first data set and the second data set, N is the set of valid locations for both the first dataset and the second dataset and w are weights used to allow points further from a center of the pattern to be given more weight in the similarity score M than points closer to the center, and the parameter p is an integer greater than zero.

2. Apparatus according to claim 1 , wherein the computer is further used to output an indication of whether the identity of the subject is authenticated or not based on the comparison.

3. Apparatus according to claim 1 , wherein in addition to the plural discrete points there are other elements in the reflected image.

4. Apparatus according to claim 3 , wherein the other elements are used to automatically determine that an eye is present and properly focused.

5. Apparatus according to claim 1 , wherein the image capture device comprises a telecentric lens and an image sensor arranged, in use, coaxially with the cornea, and eye, of the subject.

6. Apparatus according to claim 1 , wherein an alignment device is incorporated into the apparatus to ensure the subject's eye is properly aligned before an image is captured.

7. Apparatus according to claim 1 , wherein an automatic focus device is incorporated into the apparatus to ensure the image is properly focused before an image is captured.

8. Apparatus according to claim 1 , wherein the intensity of the lights is varied when they are ON, either all together or each light independently.

9. Apparatus according to claim 1 , in combination with a remote secure reference repository and a secure communications link between them.

10. A method for authenticating a subject, comprising the steps of:

capturing an image of an illuminated pattern, made up of a first set of plural discrete points, after reflection in at least a part of the cornea of an eye of the subject;

comparing locations of the first set of plural discrete points in the pattern of the captured image against the locations of a second set of plural discrete points in the pattern of a reference image according to:

M

=

∑

n

∈

N

⁢

⁢

w

n

⁢



A

n

-

B

n



p

∑

n

∈

N

⁢

⁢

w

n

where M is a similarity score between the first data set and the second data set, N is the set of valid locations for both the first set and the second set, w are weights used to allow points further from a center of the pattern to be given more weight in the similarity score M than points closer to the center, and the parameter p is an integer greater than zero; and,

authenticating the identity of the subject depending on the similarity of comparison.

11. A method according to claim 10 , wherein the image is captured after specular reflection of the pattern.

12. A method according to claim 10 , wherein the image capture step involves capturing two images, one with the pattern illuminated and the other with the pattern not illuminated.

13. A method according to claim 10 , wherein authentication relies upon a comparison between the locations of the first set of discrete points in a currently captured image and the locations of the second set of discrete points of one or more previously obtained reference images.

14. A method according to claim 10 , wherein authentication relies upon a comparison between the locations of the first set of discrete points in a currently captured image and the locations of the second set of discrete points of a series of reference images of a variety of subjects, including the present subject.

15. A method according to claim 10 , including the further step of extracting a data set defining the locations of the first set of discrete points in the captured image.

16. A method according to claim 10 , wherein the locations are represented in Cartesian (X, Y) or polar (r, θ) coordinates in the current image and the reference image(s).

17. A method according to claim 10 , wherein the locations are represented as a difference (δ) between the location measured and the original pattern or the pattern after reflection in a reference surface.

18. A method according to claim 10 , wherein the comparison involves measurements of either the current or the reference images, or both, at a degree of accuracy required by the authentication process.

19. A method according to claim 10 , wherein the comparison involves the use of different weightings (w) applied to different points of the pattern.

20. A method according to claim 10 , comprising the further step of denying authentication when there is an exact match between the locations of the first set of discrete points in the current image and the locations of the second set of discrete points in the reference image.

21. A non-transitory computer-readable medium that provides instructions, which when executed by a computer, cause the computer to perform the operations of claim 10 .