Two Stage Framework for Altered Fingerprint Matching

Fingerprint alteration is the process of masking one's identity from personal identification systems especially in boarder control security systems. Failure of matching the altered fingerprint of the criminals against the watch list of fingerprints can help them to break the security system. This fact leads to the need of a method for altered fingerprint matching. This paper presents a two stage method for altered fingerprint matching. In first stage, approximated global ridge orientation field of altered fingerprint is matched against the orientation field of its unaltered mate. If this matching is successful, fingerprints go to second stage. Second stage starts with the selection of unaltered region from the altered FP and same region from the unaltered mates. Matching in this stage is performed by extraction of ridge texture and ridge frequency from the selected region of interest. Euclidian distance is used in both stages to compute the matching score.