Mutual information analysis of JPEG2000 contexts

Zhen Liu, Lina Karam

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Context-based arithmetic coding has been widely adopted in image and video compression and is a key component of the new JPEG2000 image compression standard. In this paper, the contexts used in JPEG2000 are analyzed using the mutual information, which has a direct link with the compression performance. We first show that, when combining the contexts, the mutual information between the contexts and the encoded data will decrease unless the conditional probability distributions of the combined contexts are the same. Given I, the initial number of contexts, and F, the final desired number of contexts, there are S(I,F) possible context classification schemes where S(I,F) is called the Stirling number of the second kind. The optimal classification scheme is the one that gives the maximum mutual information. Instead of exhaustive search, the optimal classification scheme can be obtained through a modified Generalized Llyod algorithm with the relative entropy as the distortion metric. For binary arithmetic coding, the search complexity can be reduced by using the dynamic programming. Our experimental results show that the JPEG2000 contexts capture very well the correlations among the wavelet coefficients. At the same time, the number of contexts used as part of the standard can be reduced without loss in the coding performance.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsB. Vasudev, T.R. Hsing, A.G. Tescher, T. Ebrahimi
Number of pages10
Volume5022 I
StatePublished - 2003
EventImage and Video Communications and Processing 2003 - Santa Clara, CA, United States
Duration: Jan 21 2003Jan 24 2003


OtherImage and Video Communications and Processing 2003
Country/TerritoryUnited States
CitySanta Clara, CA


  • Context based arithmetic coding
  • Image compression
  • JPEG2000
  • Mutual information

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics


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