Claims
- 1. A method of producing a binary fingerprint image from a gray-scale image, said method comprising: classifying pixels based, at least in part, on, for a particular pixel, the gray-level topological relationship with neighboring pixels.
- 2. The method of claim 1, wherein classifying pixels based, at least in part, on, for a particular pixel, the gray-level topological relationship with neighboring pixels comprises:
classifying pixels based, at least in part, on, for a particular pixel, the gradient of the gray-level with at least some immediately adjacent pixels.
- 3. The method of claim 2, wherein the pixels are classified into one of multiple classes, based, at least in part, on, for a particular pixel, the gradient of the gray-level with at least some immediately adjacent pixels.
- 4. The method of claim 3, wherein the pixels are classified into one of at least four classes, based, at least in part, on for a particular pixel, the gradient of the gray-level with all immediately adjacent pixels.
- 5. The method of claim 3, wherein three of the classes comprise:
crest, plateau and valley.
- 6. The method of claim 3, 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.
- 7. The method of claim 6, and further comprising: thinning any resulting ridge lines to be one pixel thick.
- 8. The method of claim 1, wherein said gray-scale image comprises a gray-scale fingerprint image
- 9. 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, said method comprising: classifying pixels based, at least in part, on, for a particular pixel, the gray-level topological relationship with neighboring pixels.
- 10. The article of claim 9, wherein said instructions, when executed, result in classifying pixels based, at least in part, on, for a particular pixel, the gray-level topological relationship with neighboring pixels in a manner that further comprises classifying pixels based, at least in part, on, for a particular pixel, the gradient of the gray-level with at least some immediately adjacent pixels.
- 11. The article of claim 10, wherein said instructions, when executed, result in classifying pixels based, at least in part, on, for a particular pixel, the gradient of the gray-level with at least some immediately adjacent pixels in a manner wherein the pixels are classified into one of multiple classes, based, at least in part, on, for a particular pixel, the gradient of the gray-level with at least some immediately adjacent pixels.
- 12. The article of claim 11, wherein said instructions, when executed, result in classifying pixels in a manner wherein the pixels classified into one of multiple classes are classified into one of at least four classes, based, at least in part, on for a particular pixel, the gradient of the gray-level with all immediately adjacent pixels.
- 13. The article of claim 11, 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.
- 14. The article of claim 13, wherein said instructions, when executed, further result in thinning any resulting ridge lines to be one pixel thick.
- 15. The article of claim 9, wherein said instructions, when executed, result in performance of a method of producing a binary image from a gray-scale image,
- 16. An apparatus comprising: an integrated circuit;
said integrated circuit being adapted to classify pixels of a gray-scale image based, at least in part, on, for a particular pixel, the gray-level topological relationship with neighboring pixels.
- 17. The apparatus of claim 14, wherein said gray-scale image comprises a gray-scale fingerprint image.
- 18. The apparatus of claim 16, wherein said integrated circuit is further adapted to classify pixels in a manner wherein the pixels are classified into one of at least four classes, based, at least in part, on for a particular pixel, the gradient of the gray-level with all immediately adjacent pixels.
- 19. The apparatus of claim 18, 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.
- 20. The apparatus of claim 19, wherein said integrated circuit is further adapted to thin any resulting ridge lines to be one pixel thick.
RELATED APPLICATIONS
[0001] This patent application is related to concurrently filed U.S. patent application Ser. No. ______, (attorney docket 042390.P12798) titled “Method and Apparatus to Reduce False Minutiae from a Binary Fingerprint Image,” filed on ______, by Acharya et al., and to concurrently filed U.S. patent application Ser. No. ______, (attorney docket 042390.P12877) titled “Architecture for Processing Fingerprint Images,” filed on ______, by Acharya et al., both assigned to the assignee of the presently claimed subject matter and herein incorporated by reference.