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Adaptive multi-stage vector quantization

  • US 5,398,069 A
  • Filed: 03/26/1993
  • Issued: 03/14/1995
  • Est. Priority Date: 03/26/1993
  • Status: Expired due to Term
First Claim
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1. In a multi-stage vector quantization encoder comprising a plurality of consecutive vector quantization stages wherein each stage comprises a vector quantizer and an associated codebook containing a plurality of codevectors, there being a unique address associated with each codevector in the codebook of each stage, a method comprising the steps of:

  • p1 (a) receiving a data vector indicative of a block of data to be compressed;

    (b) selecting a codevector from the codebook at an initial stage that most closely resembles the data vector, generating a residual vector, and proceeding directly to step (e) if a measure of quantization error at that stage satisfies a threshold value, but otherwise first performing the following steps (c) and (d);

    (c) at a next succeeding stage, selecting a codevector from the codebook at that stage that most closely resembles the residual vector from the immediately preceding stage, and generating another residual vector;

    (d) repeating said step (c) until a measure of quantization error at a particular stage satisfies the threshold value; and

    then(e) transmitting addresses of each codevector selected in said steps (b) and (c) to a remote location.

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