Ridge orientation estimation and verification algorithm for fingerprint enhancement

Limin Liu*, Tian-Shyr Dai

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Fingerprint image enhancement is a common and critical step in fingerprint recognition systems. To enhance the images, most of the existing enhancement algorithms use filtering techniques that can be categorized into isotropic and anisotropic according to the filter kernel. Isotropic filtering can properly preserve features on the input images but can hardly improve the quality of the images. On the other hand, anisotropic filtering can effectively remove noise from the image but only when a reliable orientation is provided. In this paper, we propose a ridge orientation estimation and verification algorithm which can not only generate an orientation of ridge flows, but also verify its reliability. Experimental results show that, on average, over 51 percent of an image in the NIST-4 database has reliable orientations. Based on this algorithm, a hybrid fingerprint enhancement algorithm is developed which applies isotropic filtering on regions without reliable orientations and anisotropic filtering on regions with reliable orientations. Experimental results show the proposed algorithm can combine advantages of both isotropic and anisotropic filtering techniques and generally improve the quality of fingerprint images.

Original languageEnglish
Pages (from-to)1426-1438
Number of pages13
JournalJournal of Universal Computer Science
Issue number10
StatePublished - 1 Dec 2006


  • Enhancement
  • Fingerprint
  • Gabor filter
  • Orientation estimation


Dive into the research topics of 'Ridge orientation estimation and verification algorithm for fingerprint enhancement'. Together they form a unique fingerprint.

Cite this