Apparatus and method for matching image characteristics such as fingerprint minutiae
First Claim
1. A method of matching a live image and a master image having any random or nonrandom distribution of characteristic features throughout an image, comprising the steps of:
- generating a set of points representative of the characteristic features of the live image;
generating a set of points representative of the characteristic features of the master image; and
evaluating the match between the live characteristic points and the master characteristic points, said step of evaluating consisting essentially of the further steps of;
deriving the distances between a plurality of pairs of the live characteristic points;
deriving the distances between a plurality of pairs of the master characteristic points; and
comparing the live distances with the master distances to determine whether of not the live image matches the master image;
wherein the steps of deriving the distances between pairs of the live characteristic points and deriving the distances between pairs of the master characteristic points comprise for each such step the step of forming, for each point in the set of points, a spectrum of values representing the distances between the point and each other point in the set of points.
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Abstract
A system for matching images in which characteristic points of an image to be tested for a match, such as a fingerprint, are compared with characteristic points of a master image by attempting to match the distances between pairs of master characteristic points with distances between pairs of live characteristic points, whereby the coordinate system of the test image is not required to be aligned with the coordinate system of the master image. The matching system can be implemented in an identification mode in which the live image is attempted to be matched with each of a number of master images, or a verification mode in which the live image is attempted to be matched with a master image that is purported to be the same as the live image.
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Citations
11 Claims
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1. A method of matching a live image and a master image having any random or nonrandom distribution of characteristic features throughout an image, comprising the steps of:
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generating a set of points representative of the characteristic features of the live image; generating a set of points representative of the characteristic features of the master image; and evaluating the match between the live characteristic points and the master characteristic points, said step of evaluating consisting essentially of the further steps of; deriving the distances between a plurality of pairs of the live characteristic points; deriving the distances between a plurality of pairs of the master characteristic points; and comparing the live distances with the master distances to determine whether of not the live image matches the master image; wherein the steps of deriving the distances between pairs of the live characteristic points and deriving the distances between pairs of the master characteristic points comprise for each such step the step of forming, for each point in the set of points, a spectrum of values representing the distances between the point and each other point in the set of points. - View Dependent Claims (2, 3, 4)
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5. A method of identifying a person'"'"'s identity consisting essentially of the steps of:
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receiving an identification of selected live minutiae appearing in at least a portion of a selected fingerprint of the person, where the minutiae are identified by their spatial coordinates relative to a reference coordinate system and may be randomly or nonrandomly distributed throughout said fingerprint portion; deriving the distances between a plurality of pairs of the live minutiae; providing values for the distances between a plurality of pairs of selected minutiae appearing inn at least a portion of a master fingerprint wherein the minutiae may be randomly or nonrandomly distributed throughout said fingerprint portion; and comparing the live distance with the master distances to determine whether or not the live fingerprint matches the master fingerprint; wherein the steps of deriving the distances between pairs of live minutiae and providing the distances between pairs of master minutiae comprise for each such step the step of forming, for each minutia, a spectrum of values representing the distances between the minutia and each other minutia in its set of live or master minutiae. - View Dependent Claims (6, 7, 8)
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9. An apparatus for matching a live image and a master image having any random distribution of characteristic features throughout an image, comprising:
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a first means for receiving and storing a set of points representative of the characteristic features of the live image; a second means for receiving and storing a set of points representative of the characteristic features of the master image; computing means for receiving the live and the master characteristic points from the first and second means, deriving a distances between a plurality of pairs of the live characteristic points and deriving the distances between a plurality of pairs of the master characteristic points, wherein the computing means derives, for each characteristic point in each of the sets of live and master characteristic points, a spectrum of values representing the distances between the characteristic point and each other characteristic point in its set of characteristic points; and means for comparing the live distances with the master distances and initiating a predetermined activity essentially only on the basis of a match between the live distances and the master distances within a predetermined tolerance. - View Dependent Claims (10, 11)
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Specification