An improved full-search-equivalent vector quantization method using the law of cosines

Zhibin Pan, Koji Kotani, Tadahiro Ohmi

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Vector quantization (VQ) is a well-known signal compression method. In VQ, the search process to find the winner for an input vector either at the codebook generation stage or the VQ encoding stage is extremely time consuming. By using the law of cosines to estimate the Euclidean distance first, Mielikainen has developed a highly efficient full-search-equivalent algorithm. However, some computational redundancies still exist in it. In this letter, we introduce an additional new estimation for the Euclidean distance and then optimize the computing way given by Mielikainen. Mathematical analyses show that our proposed search method can improve Mielikainen's method. And experimental results of VQ encoding demonstrate that the proposed method is very search effective.

Original languageEnglish
Pages (from-to)247-250
Number of pages4
JournalIEEE Signal Processing Letters
Issue number2 PART II
Publication statusPublished - 2004 Feb
Externally publishedYes


  • Euclidean distance estimation
  • Fast search
  • The law of cosines
  • Vector quantization (VQ)

ASJC Scopus subject areas

  • Signal Processing
  • Electrical and Electronic Engineering
  • Applied Mathematics


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