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Lecture 5: Iris Recognition
Ioannis Pavlidis
COSC 6397
6397- Information Assurance
U of H
Genotype and Phenotype
• Genotype refers to a genetic constitution, or a group
sharing it.
– blood group and DNA
• Phenotype refers to the actual expression of a feature
through the interaction of genotype, development, and
– face, fingerprint, and iris
• Genotypic Error Rate is the minimum False Match Rate
(e.g., identical twins).
• Phenotypic Error Rate is the minimum False Rejection rate
(e.g., facial appearance)
COSC 6397- Information Assurance
U of H
Properties of the Iris
• The iris is composed of elastic connective tissue.
• It consists of pectinate ligaments adhering into a
tangled mesh revealing striations, ciliary
processes, crypts, rings, furrows, a corona,
sometimes freckles, and vasculature.
• Pupillary motion provides a “live ness” test in
high security applications.
COSC 6397- Information Assurance
U of H
Localization and Analysis of Iris Patterns
• We localize the inner and outer
boundaries of the iris. This is
accomplished through integrodifferential operations.
• A normalized coordinate system
is defined, which is invariant to
size (e.g., camera zoom and
distance to the eye).
• The iris pattern is encoded into
a 256-byte “IrisCode” by
demodulating it with 2D Gabor
wavelets, which represent the
texture by phasors in the
complex plane.
max( r, x0 , y0 ) G ( r ) *
COSC 6397- Information Assurance
I ( x, y )
r r , x0 , y0 2 r
U of H
Independence and DOF in IrisCodes
• It is important to establish that
there exists independent
variation in iris patterns, across
populations and across
positions in the iris.
• This is confirmed by tracking
the possibility of a bit being set.
• The fact that the plot is flat at a
value of 0.5 means that any
given bit in an IrisCode is
equally likely to be set or
COSC 6397- Information Assurance
U of H