Patent US4415796A successfully refreshed from Google Patents.
Patent EP0050842A2 successfully refreshed from Google Patents.
EP0050842A2
Expired / Lapsed
EP
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Fingerprint minutiae matcher
Assignee: De la Rue Printrak Inc
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Filing: 1981-10-22
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Granted: —
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Expires: 2001-10-22
Abstract
Abstract A machine or process for comparing fingerprints based on the correspondence between fingerspring minutiae. The pattern of minutiae in an unknown or search fingerprint is rotated and translated to obtain approximate registration with the pattern of minutiae in a known on file fingerprint. Following rotation and translation, only those search and file fingerprints that exhibit a sufficient number of mating minutiae between the fingerprints are compared further. For each pair of mating search and file minutiae, the neighboring mating minutiae are compared and an individual minutia "match score" is determined based on the degree of correspondence between the other mating pairs of minutiae within a specified neighborhood of the individual pair of mating search and file minutiae. The individual "match scores" for each of the mating minutiae are summed to yield a total score that is indicative of the correspondence between the search and the file fingerprints.
Inventors
- 👤 John Charles Elsey
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 16:55
CPC Classifications
G; G06; G06V; G06V40/00; G06V40/10; G06V40/12
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
138 words
A method employing a programmed computer for comparing the minutiae of a search fingerprint (the "search minutiae") with the minutiae of a file fingerprint (the "file minutiae") to determine if the search fingerprint closely resembles the file fingerprint comprising: (a) rotating and translating the search minutiae to determine the rotation and translation which most nearly brings the search minutiae into registration with the file minutiae; (b) pairing mating search and file minutiae; (c) computing an individual minutia score for each search minutia that has a mating file minutia based on the spatial and angular relationship between the other mating file and search minutiae located within a neighborhood of each such search minutia; and (d) summing the individual minutia scores to obtain a final match score indicative of the overall resemblance of the search fingerprint to the file fingerprint.
Claim 2
Independent Claim
138 words
A method employing a programmed computer for comparing the minutiae of a search fingerprint (the "search minutiae") with the minutiae of a file fingerprint (the "file minutiae") to determine if the search fingerprint closely resembles the file fingerprint comprising: (a) rotating and translating the search minutiae to determine the rotation and translation which most nearly brings the search minutiae into registration with the file minutiae; (b) pairing mating search and file minutiae; (c) computing an individual minutia score for each search minutia that has a mating file minutia based on the spatial and angular relationship between the other mating file and search minutiae located within a neighborhood of each such search minutia; and (d) summing the individual minutia scores to obtain a final match score indicative of the overall resemblance of the search fingerprint to the file fingerprint.
Claim 3
Dependent Claim
45 words
The method described in Claim 1 and further comprising: (a) sorting the search minutiae into angle order; (b) finding the closest neighbors for each search minutia; (c) sorting the file minutiae into angle order; and (d) computing maximum and minimum coordinates for the file minutia.
Claim 4
Independent Claim
45 words
The method described in Claimlor2 and further comprising terminating the comparison between the minutiae of a search fingerprint and the minutiae of a file fingerprint whenever the degree of registration of the search minutiae with the file minutiae fails to exceed an operator selected threshold.
Claim 5
Independent Claim
144 words
A method employing a programmed computer for comparing the minutiae of a search fingerprint (the "search minutiae") with the minutiae of a file fingerprint (the "file minutiae") to determine if the search fingerprint closely resembles the file fingerprint comprising the following steps in the order named: (a) rotating and translating the search minutiae to determine the rotation and translation which most nearly brings the search minutiae into registration with the file minutiae; (b) pairing mating search and file minutiae; (c) computing an individual minutia score for each search minutia that has a mating file minutia based on the spatial and angular relationship between the other mating file and search minutiae located within a neighborhood of each search minutia; and (d) summing the individual minutia scores to obtain a final match score indicative of the overall resemblance of the search fingerprint to the file fingerprint.
Claim 6
Independent Claim
144 words
A method employing a programmed computer for comparing the minutiae of a search fingerprint (the "search minutiae") with the minutiae of a file fingerprint (the "file minutiae") to determine if the search fingerprint closely resembles the file fingerprint comprising the following steps in the order named: (a) rotating and translating the search minutiae to determine the rotation and translation which most nearly brings the search minutiae into registration with the file minutiae; (b) pairing mating search and file minutiae; (c) computing an individual minutia score for each search minutia that has a mating file minutia based on the spatial and angular relationship between the other mating file and search minutiae located within a neighborhood of each search minutia; and (d) summing the individual minutia scores to obtain a final match score indicative of the overall resemblance of the search fingerprint to the file fingerprint.
Claim 7
Dependent Claim
63 words
The method described in Claim 4 and further comprising the following steps in the order named, and performed prior to the first step described in Claim 1: (a) sorting the search minutiae into angle order; (b) finding the closest neighbors for each search minutia; (c) sorting the file minutiae into angle order; and (d) computing maximum and minimum coordinates for the file minutia.
Claim 8
Dependent Claim
58 words
The method described in Claim 4 and further comprising the following step performed between steps (b) and (c) of Claim 4: terminating the comparison between the minutiae of a search fingerprint and the minutiae of a file fingerprint whenever the degree of registration of the search minutiae with the file minutiae fails to exceed an operator selected threshold.
Claim 9
Dependent Claim
118 words
The method described in Claim 5 or 6 wherein the step of rotating and translating the search minutiae to determine the rotation and translation which most nearly brings the search minutiae into registration with the file minutiae comprises: (a) rotating the search minutiae through a preselected set of rotations; (b) for each rotated set of search minutia constructing a histogram showing the number of coincident search and file minutiae for various translations of the search minutiae relative to the file minutiae; and (c) determining the rotation and translation to which most nearly brings the search minutia into registration with the file minutiae by comparing the magnitudes of the largest adjacent blocks of entires in each of the histograms.
Claim 10
Independent Claim
151 words
A device for comparing the minutiae of a search fingerprint (the "search minutiae") with the minutiae of a file fingerprint (the "file minutiae") to determine if the search fingerprint closely resembles the file fingerprint comprising: (a) rotating and translating means for rotating and translating the search minutiae to determine the rotation and translation which most nearly brings the search minutiae into registration with the file minutiae; (b) pairing means for pairing mating rotated and translated search and file minutiae; (c) scoring means for computing an individual minutia score for each search minutia that has a mating file minutia based on the spatial and angular relationship between the other mating file and search minutiae located within a neighborhood of each such search minutia; and (d) summing means for summing the individual minutia scores to obtain a final match score indicative of the overall resemblance of the search fingerprint to the file fingerprint.
Claim 11
Independent Claim
151 words
A device for comparing the minutiae of a search fingerprint (the "search minutiae") with the minutiae of a file fingerprint (the "file minutiae") to determine if the search fingerprint closely resembles the file fingerprint comprising: (a) rotating and translating means for rotating and translating the search minutiae to determine the rotation and translation which most nearly brings the search minutiae into registration with the file minutiae; (b) pairing means for pairing mating rotated and translated search and file minutiae; (c) scoring means for computing an individual minutia score for each search minutia that has a mating file minutia based on the spatial and angular relationship between the other mating file and search minutiae located within a neighborhood of each such search minutia; and (d) summing means for summing the individual minutia scores to obtain a final match score indicative of the overall resemblance of the search fingerprint to the file fingerprint.
Claim 12
Dependent Claim
59 words
The device described in Claim 8 and further comprising: (a) first sorting means for sorting the search minutiae into angle order; (b) finding means for finding the closest neighbors for each search minutia; (c) second sorting means for sorting the file minutiae into angle order; and (d) coordinate means for computing maximum and minimum coordinates for the file minutia.
Claim 13
Dependent Claim
51 words
The device described in Claim 8 or 9 and further comprising terminating means for terminating the comparison between the minutiae of a search fingerprint and the minutiae of a file fingerprint whenever the degree of registration of the search minutiae with the file minutiae fails to exceed an operator selected threshold.
Claim 14
Dependent Claim
129 words
The device described in Claim 8 or 9 wherein the rotating and translating means for rotating and translating the search minutiae to determine the rotation and translation which most nearly brings the search minutiae into registration with the file minutiae comprises: (a) rotating means for rotating the search minutiae through a preselected set of rotations; (b) for each rotated set of search minutiae constructing means for constructing a histogram showing the number of coincident search and file minutiae for various translations of the search minutiae relative to the file minutiae; and (c) determining means for determining the rotation and translation which most nearly brings the search minutiae into registration with the file minutiae by comparing the magnitudes of the largest adjacent blocks of entries in each of the histograms.
References Cited (Backward Citations)
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