Dynamic Iris Localisation: A Novel Approach suitable for Fake Iris Detection

Abstract

High resolution images not only provide high recognition rate but are also useful in safeguarding the iris recognition system from fake iris attack. To safeguard the iris recognition system against fake irises, one of the very popular technique is to detect the change in pupil size due to change in illumination. Many of existing methods assume that iris and pupil are circular or elliptical in nature , which is seldom true. They are actually of irregular shapes. Such methods fail in accurate iris segmentation from high resolution images. because these images show low intensity gradient across the sclera-iris boundary and iris-pupil boundary. This paper presents a novel approach of accurate iris segmentation using two images captured at two different intensities. This method is completely robust for fake iris detection because it exploits the pupil dynamics for iris localization. The success rate of accurate iris localization from high resolution image (UPOL database) is 99.45% and that from moderate resolution images (UBIRIS database) is 100%. Only occlusion-free images of UBIRIS database have been considered. The FAR and FRR values of the composite method of fake iris detection are 0.625% and 0.625% respectively.