A new method for iris pupil contour delimitation and its application in iris texture parameter estimation

Abstract

The location of the texture limits in an iris image is a previous step in the person's recognition processes. The iris localization plays a very important role because the speed and performance of an iris recognition system is limited by the results of iris localization to a great extent. It includes finding the iris boundaries (inner and outer). We present a new method for iris pupil contours delimitation and its practical application to iris texture features estimation and isolation. Two different strategies for estimating the inner and outer iris contours are used. The results obtained in the determination of internal contour is used efficiently in the search of the external contour parameters employing a differential integral operator. The proposed algorithm takes advantage of the pupil's circular form using well-known elements of analytic geometry, in particular, the determination of the bounded circumference to a triangle. The algorithm validation experiments were developed in images taken with near infrared illumination, without the presence of specular light in their interior. Satisfactory time results were obtained (minimum 0.0310 s, middle 0.0866 s, maximum 0.1410 s) with 98% of accuracy. We will continue working in the algorithm modification for using with images taken under not controlled conditions. © Springer-Verlag Berlin Heidelberg 2005.