Zero Reference Based Ridge Flow Map

• US 20140003680A1
• Filed: 03/15/2013
• Published: 01/02/2014
• Est. Priority Date: 06/29/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Marciniak, Craig A., Westerman, Wayne C., Han, Byron B.
• Granted Patent: US 9,092,652 B2
• Time in Patent Office: Days
• US Class Current: 382/124
• CPC Class Codes: G06V 40/12 Fingerprints or palmprints
• CPC Class Codes: G06V 40/1359 Extracting features related to ridge properties; Determining the fingerprint type, e.g. whorl or loop

Abstract

A method includes receiving fingerprint image data at a fingerprint recognition sensor, where the fingerprint image data are associated with an authorized user. The fingerprint image data are transformed into a substantially rotationally invariant representation, which is maintained in a database of enrolled fingerprint information. Processed fingerprint image data from an accessing user are compared with the substantially rotationally invariant representation of the fingerprint image data from the authorized user.

Claims

1. A method comprising:

receiving fingerprint image data associated with an authorized user by a fingerprint recognition sensor;

transforming the fingerprint image data associated with the authorized user into a substantially rotationally invariant representation thereof;

maintaining the substantially rotationally invariant representation of the fingerprint image data associated with the authorized user in a database of enrolled fingerprint information; and

comparing processed fingerprint image data from an accessing user with the substantially rotationally invariant representation of the fingerprint image data from the authorized user.

2. The method of claim 1, wherein comparing the processed fingerprint image data is performed in response to the accessing user attempting to match fingerprints with the authorized user.

3. The method of claim 2, further comprising authorizing the accessing user based on a match between the substantially rotationally invariant representation of the fingerprint image data from the authorized user and the processed fingerprint image data from the accessing user, wherein the fingerprint image data associated with the authorized user and the processed fingerprint image data from the accessing user are obtained at substantially different angular orientations with respect to the fingerprint recognition sensor.

4. The method of claim 1, wherein transforming the fingerprint image data associated with the authorized user comprises determining a set of directions based on gradients defined at different points in the fingerprint image data associated with the authorized user.

5. The method of claim 4, wherein transforming the fingerprint image data associated with the authorized user further comprises determining a set of differences of the directions, wherein the set of differences is substantially rotationally invariant with respect to rotation of the fingerprint image data of the authorized user.

6. The method of claim 5, further comprising determining a landmark in the fingerprint image data associated with the authorized user, wherein the set of differences is substantially rotationally invariant about the landmark.

7. The method of claim 6, wherein the landmark is based on a set of Poincare index values determined from the set of directions, and wherein the Poincare index values are indicative of a feature of the fingerprint image data associated with the authorized user.

8. The method of claim 7, wherein comparing the processed fingerprint image data comprises comparing a first histogram for the set of Poincare index values based on the fingerprint image data associated with the authorized user and a second histogram for a corresponding set of Poincare index values based on the fingerprint image data from the accessing user.

9. The method of claim 4, wherein comparing the processed fingerprint image data comprises comparing a first histogram for the set of directions based on the fingerprint image data associated with the authorized user and a second histogram for a corresponding set of directions based on the fingerprint image data from the accessing user.

10. The method of claim 5, wherein comparing the processed fingerprint image data comprises comparing a first histogram for the set of differences based on the fingerprint image data associated with the authorized user and a second histogram for a corresponding set of differences based on the fingerprint image data from the accessing user.

11. A fingerprint image processing system comprising:

a fingerprint sensor configured for receiving first fingerprint image data of an authorized user and second fingerprint image data of an accessing user, wherein the first and second fingerprint image data are oriented at substantially different angles with respect to the fingerprint sensor;

a database configured for storing a substantially rotationally invariant representation of the first fingerprint image data of the authorized user; and

a processor configured for authorizing the accessing user based on comparing the substantially rotationally invariant representation of the first fingerprint image data of the authorized user with a substantially rotationally invariant representation of the second fingerprint image data of the accessing user.

12. The system of claim 11, wherein the processor is configured to generate first and second sets of physical direction vectors characterizing first and second ridge flow maps defined by the first and second fingerprint image data, respectively.

13. The system of claim 12, wherein the substantially rotationally invariant representations of the first and second fingerprint image data comprise first and second sets of logical difference vectors defined for the first and second sets of physical direction vectors, respectively.

14. The system of claim 12, wherein the substantially rotationally invariant representations of the first and second fingerprint image data comprise sets of Poincare index values defined for the first and second sets of physical direction vectors, respectively.

15. The system of claim 14, wherein the substantially rotationally invariant representations of the first and second fingerprint image data are substantially rotationally invariant about first and second anchor points defined by the first and second sets of Poincare index values, respectively.

16. The system of claim 11, wherein the substantially rotationally invariant representations of the first and second fingerprint image data comprise first and second histogram distributions derived from the first and second fingerprint image data, respectively.

17. The system of claim 16, wherein the first and second histogram distributions characterize one or more of:

first and second sets of physical direction vectors characterizing first and second ridge flow maps defined by the first and second fingerprint image data, respectively;

first and second sets of logical difference values defined for the first and second sets of physical direction vectors, respectively; and

first and second sets of Poincare index values defined for the first and second sets of physical direction vectors, respectively.

18. A non-volatile computer readable data storage medium having program data stored thereon, the program data executable by a computer processor to perform a method comprising:

receiving first fingerprint image data from an authorized user, the first fingerprint image data oriented at a first angle with respect to a fingerprint image sensor;

transforming the first fingerprint image data from the authorized user into a substantially rotationally invariant representation thereof;

storing the substantially rotationally invariant representation of the first fingerprint image data from the authorized user in a database;

receiving second fingerprint image data from an accessing user, the second fingerprint image data oriented at a second angle with respect to the fingerprint image sensor, where the second angle is different from the first angle;

transforming the second fingerprint image data from the accessing user into a substantially rotationally invariant representation thereof;

comparing the substantially rotationally invariant transformations of the first and second fingerprint image data to determine a match; and

authorizing the accessing user, based on the match.

19. The data storage medium of claim 18, wherein the substantially rotationally invariant representations of the first and second fingerprint image data comprise first and second sets of logical difference vectors between physical direction vectors characterizing the first and second fingerprint image data, respectively.

20. The data storage medium of claim 18, wherein the substantially rotationally invariant transformations of the first and second fingerprint image data comprise first and second sets of Poincare index values characterizing ridge flow maps defined by the first and second fingerprint image data, respectively.