Process and apparatus for digital signal coding and transmission by selective replenishment in time of a vector quantizer
First Claim
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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Abstract
A data compression process and apparatus using adaptive coding of a digital signal by vector quantization being applicable to transmission of digital audio signals and digital television signals as well as other signals. Quality of the received signal under the constraint of limited transmission bit rate is improved by selective optimized local replenishment of the code-book. Selected high distortion cells are identified using the current code-book and the partitioning of the selected cells reconfigured interdependently with reconfiguration of the neighboring cells to replenish the code-book, and replenishment data transmitted to the receiver. The preferred vector quantization includes classification of the cells according to distortion criteria, the code-book being a concatenation of subcode-books which are separately replenished.
16 Citations
15 Claims
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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:
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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, and c. reconfiguring the local partitioning of said neighbourhood of said selected cell by defining one or more new representatives for said set of interdependent cells. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A process for transmitting a digital signal comprising:
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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 and further includes at least one neighbouring cell of said selected cell, and c. reconfiguring the local partitioning of said neighbourhood of said selected cell by defining one or more new representatives for said set of interdependent cells; transmitting an initial code-book prior to transmitting a useful signal, memorizing said initial code-book at the receiver, periodically replenishing said code-book using at least certain of the new sequences of the digital input signal and, after each periodic replenishment, transmitting selectively to the receiver the information for replenishment of the receiver code-book. - View Dependent Claims (12, 13, 14)
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15. A method for transmitting digital signals comprising the steps of:
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decomposing a digital input signal into blocks; transforming said blocks; image classifying said transformed blocks; and adaptively coding said image classified signal, wherein said adaptively coding comprises the steps of comparing a distortion value associated with a class of signals to a predetermined value; and modifying a code-book for translating said coded signal if said distortion value exceeds said predetermined value wherein said step of modifying comprises, identifying individual cells of said class of signals having a distortion value greater than a second distortion threshold and, modifying a set of cells associated with each of said individual cells identified wherein said modification revises said code-book.
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Specification