Patent Document ID: 20020034322
Application ID: 09873570
Patent Status: 0

Claim One:
1. A method for determining reference points in a fingerprint image, the method comprising: generating the fingerprint as a gray-scale image; dividing the gray-scale image into image areas; converting the gray-scale image by region from a position range into a frequency range via a transformation; bandpass-filtering the gray-scale image by region in the frequency range for generating a usable frequency range; computing a spectral power density for a particular image area by squaring an absolute value of the usable frequency range in a particular image area; weighting frequencies in the usable frequency range in the particular image area with a particular pertinent spectral power density to provide weighted frequencies; computing a straight regression line using the weighted frequencies for the particular image area for determining an orientation pattern of dermal ridges in the particular image area; and comparing the orientation pattern with stored reference orientation patterns of a preset number of image areas forming an image area region for identifying the reference points.