Method of correlation of images in biometric applications
First Claim
Patent Images
1. A method of comparing a first image and a second image comprising the steps of:
- (a) compressing the first image into a first image projection;
(b) compressing the second image into a second image projection;
(c) determining a deviation of symmetry of the first image projection and the second image projection by the steps of;
(i) locating a correlation peak Δ
;
(ii) performing a correlation function at a first point near the correlation peak Δ
+δ
to determine a first correlation result;
(iii) performing the correlation function at a second point near the correlation peak Δ
−
δ
to determine a second correlation result;
(iv) performing the correlation function at the correlation peak Δ
to determine a peak correlation result;
(v) computing a difference between the first correlation result and the second correlation result;
(vi) dividing the difference by the peak correlation result to determine the deviation of symmetry; and
(d) comparing the deviation of symmetry and a predetermined threshold value.
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Abstract
A method and apparatus for computing correlating images for image recognition is provided. In particular, the method is used to compare images of a biometric object to authorize an individual or verify whether an individual is the person he claims to be. The biometric objects may include fingerprints, hand or palm prints, and retina scans. The method uses a deviation of symmetry of correlation functions to determine whether the images are of a same object.
40 Citations
17 Claims
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1. A method of comparing a first image and a second image comprising the steps of:
-
(a) compressing the first image into a first image projection;
(b) compressing the second image into a second image projection;
(c) determining a deviation of symmetry of the first image projection and the second image projection by the steps of;
(i) locating a correlation peak Δ
;
(ii) performing a correlation function at a first point near the correlation peak Δ
+δ
to determine a first correlation result;
(iii) performing the correlation function at a second point near the correlation peak Δ
−
δ
to determine a second correlation result;
(iv) performing the correlation function at the correlation peak Δ
to determine a peak correlation result;
(v) computing a difference between the first correlation result and the second correlation result;
(vi) dividing the difference by the peak correlation result to determine the deviation of symmetry; and
(d) comparing the deviation of symmetry and a predetermined threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of authenticating an acquired image of an object comprising the steps of:
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compressing the acquired image into an acquired image projection;
performing a symmetry process between the acquired image projection and a reference projection of a predetermined reference image to determine a deviation of symmetry;
authenticating the acquired image by comparing the deviation of symmetry and a predetermined threshold value;
wherein the symmetry process comprising the steps of;
providing a correlation function;
locating a correlation peak;
folding the correlation function at about the correlation peak to determine a symmetry of the acquired and reference projections; and
normalizing the symmetry to determine the deviation of symmetry. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification