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Process and apparatus for digital signal coding and transmission by selective replenishment in time of a vector quantizer

  • US 4,845,559 A
  • Filed: 12/17/1987
  • Issued: 07/04/1989
  • Est. Priority Date: 12/17/1986
  • Status: Expired due to Term
First Claim
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1. A process for adaptive coding of a digital signal having a plurality of components by vector quantization, to produce a high quality coded signal under the constraint of a limited information bit rate, comprising partitioning into cells the space of possible states of the components of the digital signal, choosing a single representative for each cell, substituting for each component of the signal the representative of the cell to which it belongs, the set of representatives resulting from the partitioning forming a code-book, and locally replenishing the code-book, the replenishment comprising the steps of:

  • a. selecting cells for which coding of a new set of signal components using the current code-book produces a distortion exceeding a certain threshold;

    b. analyzing the content and occurrence of use of the code-book using the new set of signal components in each cell thus selected as well as in a neighbourhood of said selected cell wherein said neighbourhood includes a set of interdependent cells andf urther includes at least one neighbouring cell of said selected cell, andc. reconfiguring the local partitioning of said neighbourhood of said selected cell by defining one or more new representatives for said set of interdependent cells.

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