Fingerprint identification system
First Claim
1. A machine method of comparing an M×
- N data array to an X×
Y data array, said arrays being representative of fingerprint patterns, comprising the steps of;
A. dividing said X×
Y array into a plurality of sub-arrays;
B. comprising elements of a sub-array of said X×
Y array with elements of said M×
N array and generating a correlation value indicative of the degree of correlation existing between corresponding elements;
C. repeating step B for a plurality of sub-arrays of elements of said M×
N array;
D. identifying a highest correlation value generated in step C;
E. repeating steps B, C and D for each sub-array of said X×
Y array;
F. identifying a relative location of said sub-arrays corresponding to said highest correlation values to provide a measure of relative distortion of said fingerprint patterns; and
G. comparing said highest correlation values and said measure of relative distortion to respective predetermined threshold values.
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Accused Products
Abstract
A fingerprint identification system includes a scanner, a memory for storing data representative of fingerprints received from the scanner, means for comparing newly received data to reference data, and means for determining the degree of distortion and misregistration present in the new data relative to the reference data. The new data and the reference data are stored in arrays. The arrays are compared by a method which includes dividing the reference array into sub-arrays and comparing the elements of each sub-array with the elements of a number of sub-arrays of the new data array. This technique allows the reference array to be stretched and/or compressed to account for distortion and/or misregistration in the new data array. Apparatus designed to insure nominal finger registration and to protect the optical surface of the scanner from dirt, grease and other contamination is also provided.
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Citations
20 Claims
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1. A machine method of comparing an M×
- N data array to an X×
Y data array, said arrays being representative of fingerprint patterns, comprising the steps of;A. dividing said X×
Y array into a plurality of sub-arrays;B. comprising elements of a sub-array of said X×
Y array with elements of said M×
N array and generating a correlation value indicative of the degree of correlation existing between corresponding elements;C. repeating step B for a plurality of sub-arrays of elements of said M×
N array;D. identifying a highest correlation value generated in step C; E. repeating steps B, C and D for each sub-array of said X×
Y array;F. identifying a relative location of said sub-arrays corresponding to said highest correlation values to provide a measure of relative distortion of said fingerprint patterns; and G. comparing said highest correlation values and said measure of relative distortion to respective predetermined threshold values. - View Dependent Claims (2)
- N data array to an X×
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3. A machine method of comparing an M×
- N array to an X×
Y data array, said arrays being representative of fingerprint patterns, comprising the steps of;A. dividing said X×
Y array into a plurality of sub-arrays;B. comparing elements of a sub-array of said X×
Y array with elements of said M×
N array and generating a correlation value indicative of the degree of correlation existing between corresponding elements;C. repeating step B for a plurality of sub-arrays of elements of said M×
N array to generate a correlation array of said correlation values;D. identifying a highest correlation value in said correlation array; E. repeating steps B, C and D for each sub-array of said X×
Y array;F. identifying a relative location of said highest correlation values in said correlation arrays to provide a measure of relative distortion of said fingerprint patterns; and G. comparing said highest correlation values and said measure of relative distortion to respective predetermined threshold values. - View Dependent Claims (4)
- N array to an X×
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5. Apparatus for comparing an M×
- N data array to an X×
Y data array, said arrays being representative of fingerprint patterns, comprising;means for dividing said X×
Y array into a plurality of sub-arrays;means for comparing elements of each sub-array of said X×
Y array with elements of a plurality of sub-arrays of said M×
N array and for generating a correlation value indicative of the degree of correlation existing between elements of each of said sub-arrays and corresponding elements of said plurality of sub-arrays;means for identifying a highest of said correlation values for each sub-array; means for identifying a relative location of said sub-arrays corresponding to said highest correlation values to provide a measure of relative distortion of said fingerprint patterns; and means for comparing said highest correlation values and said measure of relative distortion to respective predetermined threshold values. - View Dependent Claims (6, 7, 8, 9, 10, 11)
- N data array to an X×
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12. Apparatus for identifying fingerprint patterns, comprising:
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memory means for storing at least one X×
Y data array representative of a first fingerprint pattern;scanning means for scanning a second fingerprint pattern and for generating an M×
N data array representative of said second fingerprint pattern;correlation means for comparing said M×
N data array with said at least one X×
Y data array and for generating a correlation value representative of said comparison;distortion correction means for compensating for a degree of distortion and misregistration of said second fingerprint pattern relative to said first fingerprint pattern and for generating a measure of relative distortion representative of said degree of distortion; and threshold means for producing an indication signal when said correlation value and said measure of relative distortion are compared to respective threshold values. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification