Fig. 2 illustrates an example of an iris image and its iris code. The positive coefficients are represented by a white line and the negatives by a black line. For the Matching step, a distance measure between a generated iris code and stored iris code is calculated. The query iris is considered authentic if the distance measure is below a threshold. Daugman has considered the quality of the iris image, and extracted a matching mask from the iris image. He used the Hamming distance (HD) to calculate the distance between two irises. For the identification, Daugman fixed the threshold of the matching around 0.34 [8]. The iris recognition system proposed by Daugman is often used and is a basis of all current iris recognition systems.