IrisCode
Definition
The 2048-bit binary template produced by quantising the phase of 2D Gabor wavelet responses across the normalised iris strip. Phase encoding provides photometric invariance.
- Size
- 2048-bit binary template
- Source
- 2D Gabor wavelet phase responses across normalised iris strip
- Encoding basis
- Phase, not amplitude
- Benefit of phase encoding
- Photometric invariance
Common questions
Why does IrisCode encode phase rather than the raw texture image?+
Phase information from the Gabor filter response stays stable under changes in illumination and camera gain, while amplitude varies with lighting conditions, so encoding phase lets two captures of the same iris under different lighting still produce closely matching codes.
How is the IrisCode used to compare two iris images?+
Two IrisCode templates are compared bit by bit using a Hamming distance calculation, with the fraction of differing bits providing a match score; a low fraction indicates the same iris, and the comparison can run in a fraction of a second even against very large enrolled databases.
Related terms
- DOD ABIS
- US Department of Defense Automated Biometric Identification System, administered by the Defense Forensics and Biometrics Agency, holding iris, fingerprint, face and DNA...
- Hamming Distance (HD)
- The fraction of bit positions where two IrisCodes disagree, computed only over mutually unmasked bits. Genuine pairs centre around HD 0.10-0.15; impostor...
- HIIDE
- Hand-held Interagency Identity Detection Equipment: a handheld iris and fingerprint capture device used by US military forces in Iraq and Afghanistan for...
- Integro-Differential Operator
- Daugman's boundary-detection method: it maximises the magnitude of the line-integral intensity gradient around circular paths, locating the pupillary and limbic boundaries of...
- NIST IREX
- NIST Iris Exchange: the series of iris recognition algorithm evaluations conducted by the National Institute of Standards and Technology since 2009, providing...
- Puttaswamy V. Union of India (2018)
- Supreme Court of India judgment upholding Aadhaar's constitutional validity while classifying iris and other biometric data as sensitive personal information within the...
- Rubber-Sheet Model
- The coordinate transform that maps the annular iris region (between pupillary and limbic circles) to a normalised rectangular strip of fixed dimensions,...
- UIDAI
- Unique Identification Authority of India, the statutory body created by the Aadhaar Act 2016 that operates the world's largest biometric identity system,...
- Usable Bit Fraction
- The proportion of IrisCode bits not masked for eyelid, eyelash, or specular reflection occlusion. Values below 0.7 reduce match confidence; values below...