Patent Document ID: 9070002
Application ID: 13276159
Patent Status: 1

Claim One:
1. A computer-implemented method of performing fingerprint matching, comprising the steps of: acquiring a first fingerprint image; locating a reference core point within the first fingerprint image in order to initiate feature extraction of the first fingerprint image; establishing a region of interest (ROI) around the reference core point; decomposing the region of interest into eight separate directional sub-band outputs; calculating translation, rotation, and scaling (TRS) independent moment invariants and affine moment invariants from each of the eight separate directional sub-band outputs by: calculating at least one geometric moment invariant M pq , said geometric moment invariant calculation being defined by the relation M pq =∫ −∞ ∞ ∫ −∞ ∞ x p y q f(x,y)dxdy for p, q=0, 1, 2,. .. , n, where n represents a number of stored template features, x and y are Cartesian coordinates, and f(x,y) is a continuous function; adapting the geometric moment invariant calculation to grayscale images having pixel intensities I(x,y), the geometric moment invariant calculation adaptation being characterized by the relation M Ij =Σ x Σ y x I y j I(x,y) for I,j=0, 1, 2,. .. , n; calculating at least one complex moment invariant c pq , the complex moment invariant calculation being defined by the relation c pq =∫ −∞ ∞ ∫ −∞ ∞ (x+iy) p (x−iy) q f(x,y)dxdy, where i is the complex number, the at least one complex moment invariant being based on a polynomial basis k pq characterized by the relation k pq (x,y)=(x+iy) p (x−iy) q ; and calculating at least one orthogonal moment v pq , the orthogonal moment invariant calculation being defined by the relation v pq =n p n q ∫∫ Ω p p (x)p q (y)f(x,y)dxdy, wherein n p and n q are normalized factors and Ω is an area of orthogonality, the grayscale image being scaled such that its support is contained in Ω; combining features calculated from each of the separate directional sub-band outputs into a first feature vector V f characterized by the relation V f ={I θ1 , I θ2 ,. .. , I θk }, where θε{0, 1, 2, 3, 4, 5, 6, 7}, corresponding to the eight separate directional sub-band outputs, k ε{0, 1, 2,. .. , 56}, corresponding to the independent moment invariants from each of the eight separate directional sub-band outputs, and I θk is a feature sub-block of the θ-th directional sub-band and the k-th independent moment invariant; calculating an absolute distance between the first feature vector and a second vector V f2 including features of a second fingerprint having similarly obtained moment invariants, the second vector being characterized by the relation V f2 ={b 1 , b 2 ,. .. , b n }, where each of the {b 1 , b 2 ,. .. , b n }represent one of the n stored template features; and displaying match results based on the first and second fingerprint absolute distance calculation step.