Patent ID: 8036466

Claim:
A method of approximating an iris boundary, comprising the steps of: acquiring an image of an eye, including an iris boundary; noting a plurality of unequally spaced boundary points on the boundary of the image; selecting a fixed reference point in the image; and generating an approximate boundary representation comprising a least squares approximation by a discrete cosine transform series as a function d ⁡ ( θ ) = C 0 2 + ∑ n = 1 N - 1 ⁢ C n ⁢ cos ⁢ ⁢ n ⁡ ( θ 2 + π 2 ⁢ N ) of angle θ i about said fixed point of the distance of said boundary points in the image from said fixed point; the spaced boundary points being not all equally spaced in θ i , and in which said least-squares approximation minimizes the sum of squares of errors in the distances taken over the boundary points.