Method and apparatus for automatic extraction of fingerprint cores and tri-radii

摘要

A method and apparatus for the smoothing and singularity detection of the ridge contour data of a fingerprint image for classification in an automatic fingerprint identification system. A template scanning window is passed electronically over a digital matrix of ridge contour data to generate a set of correlation values corresponding to each contour data element and to a plurality of reference angle vectors. The correlation values are processed for determination of peaks and valleys. Tests are conducted to determine whether the relative values of peaks and valleys and the relative spacing between peaks and valleys satisfy certain threshold criteria for reliable extraction of fingerprint singularity points for classification. The resultant data, representing the number of correlation peaks and the direction of each, defines the location and angular orientation of cores and deltas of a fingerprint.