A method of authenticating users is provided that includes capturing biometricauthentication data of a user and processing the captured biometric data intoan image.Moreover, the method includes determining a region of interest of the imageand a gray scaleimage from the image, determining an optimum transformation parameter setwithin the regionof interest, and aligning the gray scale image with an enrollment gray scaleimage generatedduring enrollment of the user using results of the optimum transformationparameter setdetermination. Furthermore, the method includes extracting biometric featuredata from thegray scale image and verifying an identity of the user with extractedbiometric feature dataincluded in a region of agreement.
