Commensurability of Iris Codes

A critical feature of this coding approach is the achievement of commensurability among iris codes, by mapping all irises into a representation having universal format and constant length, regardless of the apparent amount of iris detail. In the absence of commensurability among the codes, one would be faced with the inevitable problem of comparing long codes with short codes, showing partial agreement and partial disagreement in their lists of features. It is not obvious mathematically how one would make objective decisions and compute confidence levels on a rigorous basis in such a situation. This difficulty has hampered efforts to automate reliably the recognition of fingerprints. Commensurability facilitates and objectifies the code comparison process, as well as the computation of confidence levels for each decision. It thereby greatly increases both the speed and the reliability of iris recognition decisions.