Fingerprint verification method
First Claim
1. The method of fingerprint verification by comparison of a reference fingerprint image against an input fingerprint image wherein each image is composed of a field of pixels having first and second values representing respectively fingerprint ridge and valley pixels comprising the steps of:
- providing at least first and second reference segment images representing subfields from a reference fingerprint,providing at least first and second domain images representing subfields from an input fingerprint, said domain images being substantially larger than said reference segment images,scanning said first reference segment image across said first domain image and scanning said second reference segment image across said second domain image to determine significant positions, said significant positions constituting locations of maximum correlation for each reference segment image/domain image pair between pixels having said first value and also locations of maximum correlation for each reference segment image/domain image pair between pixels having said second value, andverifying the input fingerprint from which said domain images are extracted as corresponding to the reference fingerprint from which said reference segment images are extracted by subjecting at least one of said significant locations to pre-determined positional criteria.
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Accused Products
Abstract
An input fingerprint image consists of ones and zeros pixels representing light and dark pixels which in turn correspond to ridge and valley formations. This image is compared with a reference file fingerprint to verify the identity of the input fingerprint. The reference file has two relatively small segments which are subfields of the entire field of pixels that constituted the original fingerprint image for the individual involved. Two substantially larger domain subfields are extracted from the input fingerprint image. The center of each segment corresponds to the center of a respective one of the domains. Each segment is scanned over its corresponding domain to determine the position of maximum ones correlation and maximum zeros correlation between each segment and its corresponding domain. These four positions together with the correlation values associated with each of these four positions are subjected to various criteria to provide positive or negative verification of the input image relative to the reference file. These criteria include (a) positional closenes to one another, (b) exclusion of the positions from a predetermined border of the domain, (c) closeness of the correlation values of certain of the positions, and (d) magnitude of the sum of the ones correlations and zeros correlation for certain of the positions.
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Citations
32 Claims
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1. The method of fingerprint verification by comparison of a reference fingerprint image against an input fingerprint image wherein each image is composed of a field of pixels having first and second values representing respectively fingerprint ridge and valley pixels comprising the steps of:
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providing at least first and second reference segment images representing subfields from a reference fingerprint, providing at least first and second domain images representing subfields from an input fingerprint, said domain images being substantially larger than said reference segment images, scanning said first reference segment image across said first domain image and scanning said second reference segment image across said second domain image to determine significant positions, said significant positions constituting locations of maximum correlation for each reference segment image/domain image pair between pixels having said first value and also locations of maximum correlation for each reference segment image/domain image pair between pixels having said second value, and verifying the input fingerprint from which said domain images are extracted as corresponding to the reference fingerprint from which said reference segment images are extracted by subjecting at least one of said significant locations to pre-determined positional criteria. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. The system of verifying an input fingerprint image by comparison of a reference fingerprint image against an input fingerprint image wherein each image is composed of a field of pixels having first and second values representing respectively fingerprint ridge and valley pixels comprising:
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means to establish at least first and second reference segment images representing subfields from a reference fingerprint, means to establish at least first and second domain images representing subfields from an input fingerprint, said domain images being substantially larger than said reference segment images, scanning means for scanning said first reference segment image across said first domain image and scanning said second reference segment image across said second domain image to determine significant positions, said significant positions constituting locations of maximum correlation for each reference segment image/domain image pair between pixels having said first value and also locations of maximum correlation for each reference segment image/domain image pair between pixels having said second value, and means to verify the input fingerprint from which said domain images are extracted as corresponding to the reference fingerprint from which said reference segment images are extracted by subjecting at least one of said significant locations to pre-determined positional criteria. - View Dependent Claims (31, 32)
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Specification