An analysis of iriscode

Adams W.K. Kong, Dapeng Zhang, Mohamed S. Kamel

Research output: Journal article publicationJournal articleAcademic researchpeer-review

51 Citations (Scopus)


IrisCode is an iris recognition algorithm developed in 1993 and continuously improved by Daugman. It has been extensively applied in commercial iris recognition systems. IrisCode representing an iris based on coarse phase has a number of properties including rapid matching, binomial impostor distribution and a predictable false acceptance rate. Because of its successful applications and these properties, many similar coding methods have been developed for iris and palmprint identification. However, we lack a detailed analysis of IrisCode. The aim of this paper is to provide such an analysis as a way of better understanding IrisCode, extending the coarse phase representation to a precise phase representation, and uncovering the relationship between IrisCode and other coding methods. Our analysis demonstrates that IrisCode is a clustering algorithm with four prototypes; the locus of a Gabor function is a 2-D ellipse with respect to a phase parameter and can be approximated by a circle in many cases; Gabor function can be considered as a phase-steerable filter and the bitwise hamming distance can be regarded as a bitwise phase distance. We also discuss the theoretical foundation of the impostor binomial distribution. We use this analysis to develop a precise phase representation which can enhance accuracy. Finally, we relate IrisCode and other coding methods.
Original languageEnglish
Article number5276817
Pages (from-to)522-532
Number of pages11
JournalIEEE Transactions on Image Processing
Issue number2
Publication statusPublished - 1 Feb 2010


  • Biometrics
  • Daugman algorithm
  • Gabor filter
  • Iris recognition
  • Palmprint recognition
  • Phase

ASJC Scopus subject areas

  • Software
  • Computer Graphics and Computer-Aided Design


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