System for fingerprint image reconstruction based on motion estimate across a narrow fingerprint sensor

1. A method for acquiring and comparing biometric information, the method comprising:

acquiring a plurality of frames of data representing a sampled output of a swipe fingerprint sensor, wherein said acquiring comprises determining a delay factor related to a detected finger motion;

assembling said plurality of frames to form a fingerprint image, wherein said assembling comprises decimating at least one of said plurality of frames;

verifying a quality of a core area of said fingerprint image by comparing a statistical feature of said fingerprint image to a statistical model, said statistical model being derived from a population of fingerprint images;

if said assembled fingerprint image exhibits statistical features characteristic of sufficient quality, selecting a core portion of said fingerprint image having at least a portion of the core area of said fingerprint;

comparing said core portion of said fingerprint image to a plurality of different templates, wherein each different template is formed from a composite of multiple cropped verified fingerprint images associated with a different person; and

determining if said core portion of said fingerprint image matches a template.

2. A system comprising a portable electronic device, the system being configured to implement the method of claim 1 .

3. A portable electronic device having a computer configured to implement the method of claim 1 .

4. A computer-readable medium having instructions for implementation of the method of claim 1 .

5. The method of claim 1 , further comprising removing artifacts and noise from said fingerprint image before comparing and determining.

6. The method of claim 1 , further comprising removing a portion of said fingerprint image, said removed portion comprising a portion of the non-core portion of said fingerprint image.

7. The method of claim 1 , further comprising an enrollment mode for building a template.

8. The method of claim 7 , wherein said enrollment mode comprises:

acquiring a plurality of fingerprint images;

cropping each of said plurality of fingerprint images;

removing noise and artifacts from each of said cropped plurality of fingerprint images;

extracting a core portion from each of said cropped plurality of fingerprint images;

verifying a quality of said core portion of each of said cropped plurality of fingerprint images by comparing a statistical feature of each of said cropped plurality of fingerprint images to a statistical model;

combining said core portion of said-cropped plurality of fingerprint images with a correlation filter to form a composite template; and

saving said template to a database.

9. The method of claim 8 , further comprising associating said template with information identifying a person.

10. A system comprising a portable electronic device, the system being configured to implement the method of claim 9 .

11. A portable electronic device having a computer configured to implement the method of claim 9 .

12. A computer-readable medium having instructions for implementation of the method of claim 9 .

13. A fingerprint system, comprising:

a microprocessor;

a machine readable storage medium including instructions executable by the microprocessor for performing the following identification process:

acquiring a plurality of frames of data representing a sampled output of a swipe fingerprint sensor, wherein said acquiring comprises determining a delay factor related to a detected finger motion;

assembling said plurality of frames to form a fingerprint image, wherein said assembling comprises decimating at least one of said plurality of frames;

verifing a quality of a core area of said fingerprint image by comparing a statistical feature of said fingerprint image to a statistical model, said statistical model being derived from a population of fingerprint images;

if said assembled fingerprint image exhibits statistical features characteristic of sufficient quality, selecting a core portion of said fingerprint image having at least a portion of the core area of said fingerprint;

comparing said core portion of said fingerprint image to a plurality of different templates, wherein each different template is formed from a composite of multiple cropped verified fingerprint images associated with a different person; and

determining if said core portion of said fingerprint image matches a template;

the fingerprint system further comprising a swipe fingerprint sensor module coupled to said microprocessor, said swipe fingerprint sensor module comprising:

a motion detector configured to detect a presence of a finger and a direction of a finger swipe;

a swipe sensor for generating a signal representing a fingerprint; and

an image buffer configured to store frames of data derived from said signal.

14. The system of claim 13 , wherein said image buffer is configured to store at least one line of image data obtained from said swipe sensor.

15. The system of claim 13 , wherein said microprocessor executes a cropping process to limit image data to a portion of said fingerprint image when executing code to perform said identification process.

16. The system of claim 15 , wherein said microprocessor filters said cropped image data when executing code to perform said identification process.

17. The system of claim 16 , wherein said microprocessor conditions the extracted portion of said cropped image data when executing code to perform said identification process.

18. The system of claim 17 , wherein said microprocessor, in a first instance, collects an area of interest for each of said fingerprint images when executing code to perform said identification process and, in a second instance, combines said collected areas of interests for each of said fingerprint images into a composite template.

19. The system of claim 18 , wherein the area of interest of at least three fingerprint images are combined to form a template.

20. A method for authenticating a fingerprint images compnsing:

forming a fingerprint image from a plurality of frames of data representing a sampled output of a swipe fingerprint sensor, wherein said forming comprises:

determining a delay factor related to a detected finger motion; and

decimating at least one of said plurality of frames;

verifying a quality of said fingerprint image by comparing a statistical feature of said fingerprint image to statistical models based on a population of both good and poor fingerprint images.

if said image exhibits statistical features characteristic of a good fingerprint image, then selecting a cropped portion of said fingerprint image that includes a core portion of said fingerprint image; and

executing a pattern-matching algorithm to determine if said selected cropped portion of said fingerprint image matches a template from a plurality of different templates, wherein each different template is formed from a composite of multiple cropped verified fingerprint images associated with a different person.

21. The method of claim 20 , wherein said pattern-matching algorithm executing step further comprises:

calculating a two-dimensional correlation function between said fingerprint image and said template;

calculating a peak-to-side lobe ratio (PSR) of said two-dimensional correlation function results; and

comparing said PSR to a pre-specified threshold to determine if said fingerprint image matches said template.

22. The method of claim 21 further comprising generating said template from multiple cropped fingerprint core images generated from a plurality of images of a fingerprint during an enrollment process.

23. A system comprising a portable electronic device, the system being configured to implement the method of claim 21 .

24. A portable electronic device having a computer configured to implement the method of claim 21 .

25. A computer-readable medium having instructions for implementation of the method of claim 21 .