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Template Aging in Iris Biometrics : Evidence of Increased False Reject Rate in ICE 2006

Using a data set with approximately four years of elapsed time between the earliest and most recent images of an iris (23 subjects, 46 irises, 6,797 images), we investigate template aging for iris biometrics. We compare the match and nonmatch distributions for short-time-lapse image pairs, acquired with no more than 120 days of time lapse between them, to the distributions for long-time-lapse image pairs, with at least 1,200 days of time lapse. We find no substantial difference in the non-match, or impostor, distribution between the short-time-lapse and the longtime-lapse data. We do find a difference in the match, or authentic, distributions. For the image dataset and iris biometric systems used in this work, the false reject rate increases by about 50% or greater for the long-time-lapse data relative to the short-time-lapse data. The magnitude of the increase in the false reject rate varies with changes in the decision threshold, and with different matching algorithms. Our results demonstrate that iris biometrics is subject to a template aging effect.