The iris is an area " relatively stable ".
" Stable " because only some rare diseases can modify quickly appearance its.
" Relatively " because, with the age, the iris changes. One estimates at approximately
5 years the natural period of these changes.
Thus, the great period of the changes makes possible the updating of the data.
It is considered that the images are immutable.
Each eye has a very detailed and single texture.
Even captured with a weak resolution, the image of an iris contains
already more than one hundred of degrees of freedom of freedom. This is
due to the existence of a dense network and tiny tubes which ensure the
statistical independence of the irises observed. The search undertaken
in the laboratories of British Telecom shows a quasi-perfect statistical
independence between the various areas of the eye. It is thus useful to
treat the whole of surfaces of the iris.
The 2 eyes of a same person are not identical.
It is thus necessary to choose an eye for the identification. Or to
store both.
The problem of identical twin.
This problem does not exist in ocular biometrics: the image of the
eye forms part of the phenotype of the individual, and has to only see
very little with its genotype. The irises of two identical twin are thus
different.
The minimum age:
Beyond the age of approximately 24 months, the eye of the child remains
relatively stable.
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