Method and system for fingerprint authentication

• US 20030068072A1
• Filed: 10/10/2001
• Published: 04/10/2003
• Est. Priority Date: 10/10/2001
• Status: Active Grant

• Current Assignee: Activcard Ireland, Limited
• Original Assignee: Activcard Ireland, Limited
• Inventors: Hamid, Laurence
• Granted Patent: US 7,272,247 B2
• Time in Patent Office: Days
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• CPC Class Codes: G06V 40/1347 Preprocessing; Feature extraction

Abstract

An improved method and system for reading and analyzing fingerprints is disclosed. According to the present invention, fingerprints are scanned and then analyzed to determine a value in dependence upon a predetermined acquisition parameter, such as for instance one of a moisture content of the fingertip and an applied fingertip pressure. The scanned fingerprint is subsequently processed to remove “false minutiae” in dependence upon the determined value, whilst retaining authentic minutiae for user authentication. Processing the fingertip to determine a condition thereof prior to image processing results in a more selective removal of minutiae, thus resulting in a larger set of minutiae being retained for comparison to a stored biometric template.

Claims

1. A method for fingerprint authentication comprising the steps of:

a) acquiring an image of a fingertip;

b) processing the image to determine a value indicative of a predetermined acquisition parameter thereof;

c) comparing the image to a stored biometric template, the comparison process based on the determined value; and

,

d) performing one of an authentication and a rejection in dependence upon the comparison.

2. A method for fingerprint authentication according to claim 1 wherein the comparison process is selected based on the determined value, the comparison process involving different image processing steps for different determined values.

3. A method for fingerprint authentication according to claim 2 wherein the determined value is quantitatively indicative of the predetermined acquisition parameter.

4. A method for fingerprint authentication according to claim 3 wherein the predetermined acquisition parameter is selected from a group comprising:

a moisture condition of the fingertip; and

, an applied pressure of the fingertip.

5. A method for fingerprint authentication according to claim 4 wherein the comparison process uses a biometric template selected in dependence upon the determined value, different biometric templates selected for different determined values.

6. A method for fingerprint authentication according to claim 1 wherein the comparison process uses a biometric template selected in dependence upon the determined value, different biometric templates selected for different determined values.

7. A method for fingerprint authentication according to claim 5 wherein the comparison process includes the steps of:

c1) selecting an image-processing process in dependence upon the determined value;

c2) according to the selected image-processing process, processing the image to remove a subset of features contained therein; and

,

c3) comparing the processed image to the selected biometric template, wherein the biometric template is processed according to a same selected image-processing process prior to being selected for comparison.

8. A method for fingerprint authentication according to claim 5 wherein the comparison process includes the steps of:

c1) selecting an image-processing process in dependence upon the determined value;

c2) according to the selected image-processing process, processing the image to remove a subset of features contained therein;

c3) according to the selected image-processing process, processing the selected biometric template to remove a subset of features contained therein; and

,

c4) comparing the processed image to the processed selected biometric template.

9. A method for fingerprint authentication according to claim 5 wherein the biometric template is selected from a plurality of biometric templates, each biometric template of the plurality of biometric templates stored in association with a moisture condition of the fingertip.

10. A method for fingerprint authentication according to claim 5 wherein the biometric template is selected from a plurality of biometric templates, each biometric template of the plurality of biometric templates stored in association with an applied pressure of the fingertip.

11. A method for processing a fingerprint image comprising the steps of:

a) acquiring an image of a fingertip;

b) processing the acquired image to determine a value indicative of a predetermined acquisition parameter thereof; and

,

c) selecting an image-processing process in dependence upon the determined value, the image-processing process for removing a subset of features of the acquired image.

12. A method for processing a fingerprint image according to claim 11 wherein the predetermined acquisition parameter is selected from a group comprising:

a moisture condition of the fingertip; and

, an applied pressure of the fingertip.

13. A method for fingerprint authentication comprising the steps of:

a) acquiring an image of a fingertip;

b) processing the acquired image to determine a value indicative of a predetermined acquisition parameter thereof;

c) processing the acquired image according to a predetermined image-processing process to remove a subset of features from the acquired image;

d) selecting a biometric template in dependence upon the determined value, the biometric template processed according to the predetermined image-processing process;

e) comparing the processed acquired image to the biometric template; and

,

f) performing one of an authentication and a rejection in dependence upon the comparison.

14. A method for fingerprint authentication according to claim 13 including the step prior to step a) of:

providing a plurality of biometric template images of a same fingertip, each biometric template image associated with a different predetermined acquisition parameter, wherein each biometric template image is processed according to the predetermined image-processing process.

15. A method for fingerprint authentication according to claim 14 wherein the predetermined acquisition parameter is a moisture condition of the fingertip.

16. A method for fingerprint authentication according to claim 15 wherein the step of providing a plurality of biometric template images of a same fingertip includes the step of repeating for each predetermined moisture condition the steps of:

conditioning the fingertip to be in the predetermined moisture condition;

placing the conditioned fingertip onto a sensing surface; and

,

capturing an image of the conditioned fingertip.

17. A method for fingerprint authentication according to claim 14 wherein the predetermined acquisition parameter is an applied pressure of the fingertip.

18. A method for fingerprint authentication according to claim 17 wherein the step of providing a plurality of biometric template images of a same fingertip includes the step of repeating for each predetermined applied pressure the steps of:

placing the fingertip onto a sensing surface using the predetermined applied pressure; and

,

capturing an image of the fingertip.

19. A system for fingerprint authentication comprising:

a sensing area for capturing an image of a fingertip presented thereto;

a memory storage area for storing captured images therein; and

,

a processor for executing code thereon to process the captured image to determine a value indicative of an acquisition parameter thereof, and to compare the captured image to a template image according to an image-processing process selected in dependence upon the determined value.

20. A system for fingerprint authentication according to claim 19 comprising a fingertip-conditioning portion for providing a predetermined fingertip condition to a fingertip placed into contact therewith.