Patent ID: 6876757

Claim:
A method for fingerprint recognition, the method comprising the steps of: acquiring an enrolled fingerprint having a plurality of ridge curves and valleys; blocking the enrolled fingerprint to form a blocked enrolled fingerprint; separating enrolled foreground blocks from enrolled background blocks of the blocked enrolled fingerprint thereby forming an enhanced enrolled image; determining for each of the enrolled foreground blocks in the enhanced enrolled image the corresponding orientation angle and amplitude, thereby forming an orientation field of the enrolled fingerprint; extracting the minutiae from the orientation field of the enrolled fingerprint by dividing each of the enrolled foreground blocks into a plurality sub-blocks, creating a core mask, convolving each of the sub-blocks of the enrolled foreground blocks with the core mask, normalizing the results of the convolution of each of the sub-blocks of the enrolled foreground blocks with the core mask, estimating the curvature in each sub-block as proportional to the convolution of the respective sub-block, determining Poincare indices of sub-blocks having a curvature that is greater than a predetermined curvature threshold, grouping the sub-blocks having a curvature that is greater than a predetermined curvature threshold according to the corresponding Poincare index, identifying the sub-blocks having a curvature that is greater than a predetermined curvature threshold as cores and deltas according to the corresponding Poincare index, if the estimate of the curvature of a sub-block exceeds a predetermined curvature threshold, surrounding the respective sub-block with a closed curve and calculating the direction integration of the closed curve, and if the calculated direction integration is substantially zero then reducing the diameter of the closed curve and recalculating the direction integration and continue reducing the diameter of the closed curve until the value of the direction integration is non-zero; creating an enrolled fingerprint template of the enrolled fingerprint from the extracted minutiae; and storing the enrolled fingerprint template in a database.