  There is uncertainty around the effect of aging of children on biometric
characteristics impacting applications relying on biometric recognition,
particularly as the time between enrollment and query increases. Though there
have been studies of such effects for iris recognition in adults, there have
been few studies evaluating impact in children. This paper presents
longitudinal analysis from 209 subjects aged 4 to 11 years at enrollment and
six additional sessions over a period of 3 years. The influence of time,
dilation and enrollment age on iris recognition have been analyzed and their
statistical importance has been evaluated. A minor aging effect is noted which
is statistically significant, but practically insignificant and is
comparatively less important than other variability factors. Practical
biometric applications of iris recognition in children are feasible for a time
frame of at least 3 years between samples, for ages 4 to 11 years, even in
presence of aging, though we note practical difficulties in enrolling young
children with cameras not designed for the purpose. To the best of our
knowledge, the database used in this study is the only dataset of longitudinal
iris images from children for this age group and time period that is available
for research.
