Method and apparatus for providing a binary fingerprint image

• US 7,136,515 B2
• Filed: 09/13/2001
• Issued: 11/14/2006
• Est. Priority Date: 09/13/2001
• Status: Expired due to Fees

• Current Assignee: Indian Statistical Institute, Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Bhowmick, Partha, Dey, Jayanta K., Kundu, Malay K., Bishnu, Arijit, Acharya, Tinku, Bhattacharya, Bhargab B., Murthy, Chivukula Anjaneya
• Primary Examiner(s): Bali, Vikkram
• Application Number:
  US09/952,248
• Publication Number:
  US 20030053666A1
• Time in Patent Office: 1,888 Days
• Field of Search: 382/115, 382/116, 382124-128, 382224-228, 340/553, 340/5.83, 235/380, 235/382, 235/382.5, 902 3- 6, 358/474, 358/3.13
• US Class Current: 382/125
• CPC Class Codes: G06V 40/1347 Preprocessing; Feature extraction

Abstract

Embodiments of a method and/or apparatus to provide a binary image are disclosed.

Claims

1. A method of producing a binary fingerprint image from a gray-scale image having more than two gray-levels, said method comprising:

classifying individual pixels based, at least in part, on, for a particular pixel, the gray-level topological relationship with neighboring pixels;

wherein the individual pixels are classified into one of at least four classes, based, at least in part, on for a particular pixel, a gradient of the gray-level with all immediately adjacent pixels.

2. The method of claim 1, wherein three of the classes comprise:

crest, plateau and valley.

3. The method of claim 1, and further comprising:

for pixels not able to be unambiguously classified based, at least in part, on, for a particular pixel, at least some immediately adjacent pixels, classifying the pixel based, at least in part, on its gray-level value and the relationship of its gray-level value to the average gray-level value of the pixels that have been classified.

4. The method of claim 3, and further comprising:

processing the gray-scale image to provide ridge lines corresponding to the pixel classifications; and

thinning the ridge lines to be one pixel thick.

5. The method of claim 1, wherein said gray-scale image comprises a gray-scale fingerprint image.

6. An article comprising:

a storage medium, said storage medium having stored thereon instructions, that, when executed, result in performance of a method of producing a binary image from a gray-scale image having more than two gray-levels, said method comprising;

classifying individual pixels based, at least in part, on, for a particular pixel, the gray-level topological relationship with neighboring pixels.

wherein said instructions, when executed, result in classifying individual pixels in a manner wherein the individual pixels are classified into one of at least four classes, based, at least in part, on for a particular pixel, a gradient of the gray-level with all immediately adjacent pixels.

7. The article of claim 6, wherein said instructions, when executed, further result in, for pixels not able to be unambiguously classified based, at least in part, on, for a particular pixel, at least some immediately adjacent pixels, classifying the pixel based, at least in part, on its gray-level value and the relationship of its gray-level value to the average gray-level value of the pixels that have been classified.

8. The article of claim 7, wherein said instructions, when executed, further result in:

processing the gray-scale image to provide ridge lines corresponding to the pixel classifications; and

thinning the ridge lines to be one pixel thick.

9. The article of claim 6, wherein said instructions, when executed, result in performance of a method of producing a binary image from a gray-scale image.

10. apparatus comprising:

an integrated circuit, said integrated circuit being adapted to classify individual pixels of a gray-scale image having more than two gray-levels based, at least in part, on, for a particular pixel, the gray-level topological relationship with neighboring pixels, wherein said gray-scale image comprises a gray-scale fingerprint image,

and wherein said integrated circuit is further adapted to classify individual pixels in a manner wherein the individual pixels are classified into one of at least four classes, based, at least in part, on for a particular pixel, a gradient of the gray-level with all immediately adjacent pixels.

11. The apparatus of claim 10, wherein said integrate circuit is further adapted to, for pixels not able to be unambiguously classified based, at least in part, on, for a particular pixel, all immediately adjacent pixels, classify the pixel based, at least in part, on its gray-level value and the relationship of its gray-level value to the average gray-level value of the pixels that have been classified.

12. The apparatus of claim 11, wherein said integrated circuit is further adapted to:

process the gray-scale image to provide ridge lines corresponding to the pixel classifications; and

thin the ridge lines to be one pixel thick.