Abstract: A security system is provided. The security system includes a terminal system and a smart card. The terminal system generates relative fingerprint information of a user from absolute fingerprint information of the user, determines a similarity between the generated relative feature information of the user and registered relative fingerprint information of a smart card owner transmitted from the smart card to generate variation information, and applies the variation information to the user absolute fingerprint information to generate modified user absolute fingerprint information. The smart card determines the similarity between the modified user absolute feature information and registered absolute feature information of the smart card owner to perform a certification operation.

Abstract: Methods and apparatus for estimating an orientation are disclosed. Methods of estimating an orientation include: dividing a fingerprint image into first partial regions, measuring the gradient of each pixel of the fingerprint image, and estimating a representative orientation of each of the first partial regions; obtaining an improved fingerprint image by filtering the fingerprint image using a double orientation filter, and remeasuring the representative orientation of each of the first partial regions by remeasuring the gradient of each pixel of the improved fingerprint image; and dividing the first partial regions into second partial regions, and estimating the representative orientation of the second partial regions with respect to the curvatures of the first partial regions in response to the remeasured representative orientation of each of the first partial regions and the remeasured gradients of the pixels.

Abstract: In a Gabor filter, a modified Gabor mask function is generated from an original Gabor mask function. A convolution of an image is performed with the modified Gabor mask function to generate a filtered image. The modification of the original Gabor mask function to the modified Gabor mask function reduces a number of calculations during such a convolution.