Fast search method for nearest neighbor vector quantization
First Claim
1. A method for searching a codebook having a plurality of codewords for an optimum codeword for quantizing an input vector, comprising the steps of:
- calculating a lower boundary value and an upper boundary value by subtracting and adding a predetermined threshold from/to an element value corresponding to a particular position among a plurality of elements constituting the input vector;
designating, as search object codewords, codewords having element values existing between the lower boundary value and the upper boundary value among element values corresponding to the particular position in the respective codewords constituting the codebook; and
determining optimum codewords having a minimum quantization error value through full search for calculating a quantization error value with the input vector for the search object codewords.
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Abstract
A fast search method for searching for an optimum codeword for nearest neighbor vector quantization. An upper boundary value and a lower boundary value between which an optimum codeword will exist in a codebook are calculated using a distortion of a designated element in an input vector and an experimentally determined threshold. Further, a start point and an end point for codebook search are determined using a binary search method from a codebook rearranged in descending order, and a full search scheme is applied only within a search range calculated by the determined start point and end point, thereby determining an optimum codeword for nearest neighbor vector quantization.
41 Citations
10 Claims
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1. A method for searching a codebook having a plurality of codewords for an optimum codeword for quantizing an input vector, comprising the steps of:
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calculating a lower boundary value and an upper boundary value by subtracting and adding a predetermined threshold from/to an element value corresponding to a particular position among a plurality of elements constituting the input vector;
designating, as search object codewords, codewords having element values existing between the lower boundary value and the upper boundary value among element values corresponding to the particular position in the respective codewords constituting the codebook; and
determining optimum codewords having a minimum quantization error value through full search for calculating a quantization error value with the input vector for the search object codewords. - View Dependent Claims (2, 3, 4, 5)
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6. A computer-readable medium of instructions for searching a codebook having a plurality of codewords for an optimum codeword for quantizing an input vector, the instructions comprising:
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a first set of instructions for calculating a lower boundary value and an upper boundary value by subtracting and adding a predetermined threshold from/to an element value corresponding to a particular position among a plurality of elements constituting the input vector;
a second set of instructions for designating, as search object codewords, codewords having element values existing between the lower boundary value and the upper boundary value among element values corresponding to the particular position in the respective codewords constituting the codebook; and
a third set of instructions for determining optimum codewords having a minimum quantization error value through full search for calculating a quantization error value with the input vector for the search object codewords. - View Dependent Claims (7, 8, 9, 10)
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Specification