Hierarchical Decomposition of Extended Triangulation for Fingerprint Indexing

In biometric identification systems, the identity corresponding to the query image is determined by comparing it against all images in the database. This exhaustive matching process increases the response time and the number of false positives of the system. This chapter presents an efficient indexing algorithm for fingerprint databases to improve the search speed and accuracy of identification. A variant of Delaunay triangulation called extended triangulation is used to make the system robust against distortions. Then the triangles are partitioned into groups such that the retrieval algorithm searches in reduced space of the database. Experiments are conducted on different fingerprint databases, and the results show that while maintaining high hit rate the proposed method achieves lower penetration rate than what existing methods achieve.