Adaptive iris matching database indexing

An adaptive iris matching approach 58 for processing images of irises having a quality not sufficient for conventional non-adaptive matching approaches 43. Visible regions (23) in a radial direction of an iris may be processed 48 without segmenting a circumference of the iris. A boundary of the visible region of the iris may also be estimated 49. An iris map may be constructed 51 with the non-visible portion of the iris masked. The iris map may be at least partially encoded 52. Partial codes of the iris map may be extracted 53 to index at least portions of a database containing iris information. Iris images may be retrieved 54 from the database with an iris code as a query. The adaptive matching approach may be incorporated into a system which evaluates image quality 42 and chooses the adaptive or non-adaptive method accordingly.