Efficient iris localisation using a guided filter

Biometric information is widely used in user identification systems. Iris is one of the most reliable and accurate biometric information. In an iris recognition system, the iris localisation is one the most important parts because the performance of an iris recognition system is highly dependent on the accuracy of iris localisation. If unreliable iris regions are used in the iris recognition system, the recognition rate may be degraded. Therefore many researchers have studied the iris localisation methods. Especially, localising an iris region from noisy images is one of the hot topics in the iris recognition researches. In this study, the authors are concentrating on the iris localisation, where an efficient iris localisation method for noisy iris images is proposed. The proposed iris localisation method consists of two steps: pupil boundary localisation and iris boundary localisation. To localise a pupil region, an efficient block-based minimum energy detection method is used, in which specular reflection removal is performed as a preprocessing. Iris boundary is localised using a guided filter, the circular Hough transform and an ellipse fitting method. Experimental results with various test image sets show the effectiveness of the proposed method.