Fingerprint security systems in handheld electronic devices and methods therefor

• US 20040125993A1
• Filed: 12/30/2002
• Published: 07/01/2004
• Est. Priority Date: 12/30/2002
• Status: Abandoned Application

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Wabgaonkar, Harshawardhan, Zhao, Yilin, Lo, Peter Zhen-Ping
• Application Number:
  US10/331,515
• Publication Number:
  US 20040125993A1
• Time in Patent Office: Days
• US Class Current: 382/124
• CPC Class Codes: G06V 40/12 Fingerprints or palmprints
• CPC Class Codes: H04M 1/67 by electronic means
• CPC Class Codes: H04M 2250/12 including a sensor for measuring a physical value, e.g. temperature or motion
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

Fingerprint image processing methods for fingerprint security systems, for example, in wireless communications devices, including capturing fingerprint images (320), identifying features from images (330), matching the identified features with reference features (340), and providing access to the device based upon feature matching (350) results. In one embodiment, minutiae features are extracted from the image and matched to reference minutiae features.

Claims

4. A fingerprint information processing method, comprising:

capturing a fingerprint image having a plurality of pixels with corresponding intensity values;

increasing a range of intensity values of the fingerprint image pixels;

enhancing the fingerprint image having the increased range of intensity values;

identifying minutiae of the enhanced fingerprint image.

5. The method of claim 4, local contrast enhancing the fingerprint image before increasing a range of intensity values.

6. The method of claim 4, convolving the fingerprint image with a sinusoidally-modulated Gaussian kernel before increasing the range of intensity values.

7. The method of claim 4, enhancing the fingerprint image by iteratively performing pixel direction image estimation, pixel direction image enhancement, and pixel intensity enhancement, at least once.

8. The method of claim 4, binarizing the enhanced fingerprint image by performing a thresholding operation.

9. The method of claim 4, thinning the enhanced fingerprint image before identifying minutiae.

10. The method of claim 9, de-whiskering the thinned fingerprint image.

11. The method of claim 9, filling broken ridges of the enhanced fingerprint image before thinning.

12. The method of claim 4, breaking weak connections of the enhanced fingerprint image before thinning.

13. A fingerprint information processing method, comprising:

forming a fingerprint image comprising pixels;

identifying minutiae of the fingerprint image;

determining confidence information for each minutia,

the confidence information based on pixel direction in a neighborhood of each minutia, continuity of any ridges connected to each minutia, and continuity of ridges neighboring each minutia.

14. The method of claim 13, identifying false minutiae by comparing the confidence information of each minutia to a confidence threshold.

16. The method of claim 13,

selecting a subset of minutiae based on the confidence information,

comparing the selected subset of minutiae to a reference subset of minutiae derived from a negative image of the fingerprint image,

eliminating minutiae from the selected subset of minutiae not having corresponding minutiae in the negative image.

17. The method of claim 13, enhancing the fingerprint image before detecting minutiae by iteratively performing at least one of gray-level statistics calculation, pixel direction image estimation, pixel direction image enhancement, and pixel intensity enhancement.

18. The method of claim 17, thinning the enhanced fingerprint image before detecting minutiae.

15. The method 14, dynamically changing the confidence threshold based on the number of minutiae detected.

19. A fingerprint information processing method, comprising:

forming an enhanced fingerprint image comprised of pixels;

identifying minutiae of the fingerprint image;

determining confidence information for each minutiae;

comparing confidence information of the minutiae to a dynamically changing confidence threshold.

20. The method of claim 19, dynamically changing the confidence threshold based upon the number of minutiae detected.

21. A fingerprint information processing method, comprising:

forming a fingerprint image comprised of pixels;

identifying minutiae of the fingerprint image;

forming a negative image of the fingerprint image;

eliminating minutiae from the minutiae identified not having corresponding minutiae in a negative image of the fingerprint image.

22. The method of claim 21,

determining confidence information for each minutia;

selecting a subset of minutiae from the minutiae identified based on the confidence information by comparing the confidence information of the detected minutiae to a dynamically changing confidence threshold;

eliminating minutiae from the subset of minutiae not having corresponding minutiae in a negative image of the fingerprint image.

23. A fingerprint information processing method, comprising:

capturing a plurality of fingerprint images, each fingerprint image having a plurality of pixels with corresponding intensity values;

extracting minutiae from a binarization of each of the fingerprint images,

selecting minutiae extracted from at least two of the binarized fingerprint images;

determining a matching threshold based upon a comparison of the minutiae selected.

24. The method of claim 23, enhancing the fingerprint image by performing at least one of gray-level statistics calculation, pixel direction image estimation, pixel direction image enhancement, and pixel intensity enhancement, at least once.

25. The method of claim 23 thinning the enhanced fingerprint image before extracting minutiae.

26. A fingerprint information processing method, comprising:

determining alignment of file and search fingerprint minutiae for a plurality of orientations of the file and search fingerprint minutiae;

selecting at least one orientation of the file and search fingerprint minutiae having a greater degree of alignment than other orientations of the file and search fingerprint minutiae;

determining similarity between the file and search fingerprint minutiae by comparing a measure of the alignment of the at least orientation selected to a similarity threshold.

1. A handheld electronics device, comprising:

a housing;

a processor coupled to memory;

a plurality of at least two non-optical fingerprint detectors coupled to the processor,

the plurality of non-optical pressure sensitive fingerprint detectors disposed on the housing of the handheld electronics device and accessible from an outer side of the housing.

2. The handheld electronics device of claim 1 is a mobile wireless communications device, a wireless transceiver coupled to the processor.

3. The handheld electronics device of claim 1, the non-optical fingerprint detectors are pressure sensitive capacitive sensors.

27. The method of claim 26, selecting orientations for aligning the file and search fingerprint minutiae based upon differences in minutiae coordinate components.

28. The method of claim 27, selecting orientations for aligning the file and search fingerprint minutiae based upon a highest frequency of differences in minutiae coordinate components.

29. The method of claim 26,

determining neighbor minutiae for each of the aligned file and search fingerprint minutiae for each orientation selected;

determining alignment of neighbor minutiae based upon a measured variance of neighbor minutiae.

30. The method of claim 29, determining alignment of neighbor minutiae based upon a comparison of neighbor minutiae density for aligned minutiae of the file and search fingerprints.

31. The method of claim 26,

determine a density of minutiae in a neighborhood of matched minutiae for each of the file and minutia fingerprints;

comparing the minutiae density of the file and search fingerprints.

32. A method in a wireless communications device, that communicates in communications networks, having a fingerprint security system, comprising:

capturing a fingerprint image at the mobile wireless communications device;

identifying fingerprint minutiae features from the fingerprint image;

matching the fingerprint minutiae features with the reference minutiae features;

providing access to the mobile wireless communications device based upon the matching of the fingerprint minutiae features with the reference minutiae features.

33. The method of claim 31, determining confidence information for each of the minutia, disregarding minutia having confidence information less than a confidence threshold that changes dynamically based upon the number of minutiae extracted.

34. The method of claim 31,

determining confidence information for each minutia detected, the confidence information based on pixel direction in a neighborhood of each minutia, continuity of any ridges connected to each minutia, and continuity of ridges neighboring each minutia.

35. The method of claim 31, increasing a range of intensity values of the fingerprint image, enhancing the fingerprint image having the increased range of intensity values, identifying minutiae of the enhanced fingerprint image.

36. The method of claim 31, preventing access to the mobile wireless communications device with the fingerprint security system after a predetermined period of inactivity of the mobile wireless communications device.

37. The method of claim 31, forming a negative image of the fingerprint image, eliminating minutiae not having corresponding minutiae in a negative image of the fingerprint image.

32-1. The method of claim 31, transmitting the fingerprint minutiae features to a network, determining whether the fingerprint minutiae features match reference minutiae features at the network.