Accurate iris localization using contour segments

We consider the problem of locating pupillary and limbic boundaries in iris images captured in non-cooperative environment. This work presents an efficient segment search algorithm, which takes advantage of shape information and learned iris boundary detectors, to enable exclusion of most noisy edges and extraction of genuine pupillary contour segments. Pupillary boundaries can then be accurately fitted as ellipses using the extracted segments. To locate limbic boundaries more stably, the shapes of pupillary boundaries constrain limbic boundary localization by adding inferred points during ellipse fitting. Extensive experiments on the challenging CASIA-Iris-Thousand iris image database demonstrate the effectiveness and efficiency of the proposed method.