Longest line method and apparatus for fingerprint alignment
First Claim
1. A method for storing a set of reference metrics for a fingerprint in a reference storage, comprising the steps of:
- scanning said fingerprint to obtain a reference image in a reference coordinate system;
selecting a first and a second constraint and defining a space on said fingerprint image;
defining a first subspace on said space and generating a first line segment within said first subspace in accordance with a third constraint;
measuring a first reference set of metrics for said first line segment, determining a fourth constraint using said first constraint and said first reference set of metrics, and defining a second subspace on said space according to said fourth constraint;
generating a second line segment within said second subspace according to said third constraint;
measuring a second reference set of metrics for said second line segment, determining a fifth constraint from said second reference sets of metrics and said first constraint, and defining a third and a fourth subspace on said space according to said fourth and fifth constraints;
generating a third line segment within said third subspace according to said second, fourth, and fifth constraints, and said first set of reference metrics;
generating a fourth line segment within said fourth subspace according to said second, fourth, and fifth constraints, and said second set of reference metrics; and
storing said first to fourth reference sets of metrics in said reference storage.
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Accused Products
Abstract
A non-minutia method and apparatus for comparing a reference fingerprint image to a candidate fingerprint image are disclosed. During enrollment of a reference image, a unique reference set of data is generated in a reference coordinate system by placing a group of line segments on the reference image. A collection of constraints is used for defining the subspace for each line of the reference group. A similar set of candidate line segments is constructed on the candidate fingerprint image in a candidate coordinate system. A candidate set of data is determined and then compared with the reference set of data using translation and rotation of the coordinate systems. Tolerances of the comparison are also provided for.
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Citations
9 Claims
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1. A method for storing a set of reference metrics for a fingerprint in a reference storage, comprising the steps of:
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scanning said fingerprint to obtain a reference image in a reference coordinate system; selecting a first and a second constraint and defining a space on said fingerprint image; defining a first subspace on said space and generating a first line segment within said first subspace in accordance with a third constraint; measuring a first reference set of metrics for said first line segment, determining a fourth constraint using said first constraint and said first reference set of metrics, and defining a second subspace on said space according to said fourth constraint; generating a second line segment within said second subspace according to said third constraint; measuring a second reference set of metrics for said second line segment, determining a fifth constraint from said second reference sets of metrics and said first constraint, and defining a third and a fourth subspace on said space according to said fourth and fifth constraints; generating a third line segment within said third subspace according to said second, fourth, and fifth constraints, and said first set of reference metrics; generating a fourth line segment within said fourth subspace according to said second, fourth, and fifth constraints, and said second set of reference metrics; and storing said first to fourth reference sets of metrics in said reference storage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification