Algorithm 1. The algorithm of Scan-and-Cluster for saliency points estimation of iris outer boundary.

(1) Define the scanning area from 0.25× to 0.75× height of the ROI of estimated iris mask.

(2) Search all the points within the range for the right and left side of ROI.

(3) Repeatedly do following step for all points:

(a) Compute all possible paired distance of two points using Equation (1).

(b) Find the maximum value of distance.

(c) Form a set Ω consisting of all distance values computed from (b).

(4) Apply K-means algorithm with the value of k = 2 on set Ω. Suppose the subset Θ denotes the cluster that has higher value.

(5) Saliency points are recovered as all the end points corresponding to all lines that belonged to Θ.