com.machinezoo.sourceafis

Class FingerprintMatcher

SourceAFIS » API Reference




  • public class FingerprintMatcher
    extends Object
    Fingerprint template representation optimized for fast 1:N matching. FingerprintMatcher maintains data structures that improve matching speed at the cost of some RAM. It can efficiently match one probe fingerprint to many candidate fingerprints.
    New matcher is created by passing probe fingerprint template to index(FingerprintTemplate) on an empty fingerprint matcher instantiated with FingerprintMatcher() constructor. Candidate fingerprint templates are then passed one by one to match(FingerprintTemplate).
    See Also:
    SourceAFIS overview, FingerprintTemplate
    • Method Detail

      • match

        public double match(FingerprintTemplate candidate)
        Match candidate fingerprint to probe fingerprint and calculate similarity score. Candidate fingerprint in candidate parameter is matched to probe fingerprint previously passed to index(FingerprintTemplate).
        Returned similarity score is a non-negative number that increases with similarity between probe and candidate fingerprints. Application should compare the score to a threshold with expression (score >= threshold) to arrive at boolean match/non-match decision. Threshold 10 corresponds to FMR (false match rate) of 10%, threshold 20 to FMR 1%, threshold 30 to FMR 0.1%, and so on.
        Recommended threshold is 40, which corresponds to FMR 0.01%. Correspondence between threshold and FMR is approximate and varies with quality of fingerprints being matched. Increasing threshold rapidly reduces FMR, but it also slowly increases FNMR (false non-match rate). Threshold must be tailored to the needs of the application.
        This method is thread-safe. Multiple threads can match candidates against single FingerprintMatcher.
        Parameters:
        candidate - fingerprint template to be matched with probe fingerprint indexed by this FingerprintMatcher
        Returns:
        similarity score between probe and candidate fingerprints
        See Also:
        index(FingerprintTemplate)