1. A fingerprint feature correlator for high-speed verification of a person's identity, comprising: a fingerprint sensor, for generating a digital image of a fingerprint; an enrollment processor for extracting, from a fingerprint image generated by the fingerprint sensor from the fingerprint of an identified person, multiple reference patches that together uniquely identify the image, each reference patch containing a plurality of fingerprint ridge or valley bifurcation features; reference image storage means, for storing reference patch images and locations provided by the enrollment processor; a correlation processor, for searching an entire subject fingerprint image generated by the fingerprint sensor from the fingerprint of a person seeking identity verification, for instances of pixel patterns similar to the stored reference patch images, and for generating a set of candidate match locations in the subject image; a geometric constraint checking processor, for attempting to locate in the set of candidate match locations a subset of candidate match locations that is geometrically congruent with a corresponding subset of reference patch locations, to a desired degree of accuracy, and for determining whether there is a match between the subject image and the stored reference image; and an image preprocessor, for converting the digital image of the fingerprint to binary form and to a standard orientation; and wherein the enrollment processor includes means for thinning the binary image to obtain skeletal images of ridges and valleys in the fingerprint; means for analyzing the skeletal images to locate bifurcation features in the ridges and valleys; means for selecting reference patches based on feature density, and storing the reference patch positions in the reference image storage means; and means for extracting reference patch images from the skeletal images of the ridges and valleys and storing the reference patch images in the reference image storage means with the corresponding reference patch locations.