ISSN : 1796-217X
Volume : 4    Issue : 4    Date : June 2009

Lossless Compression Schemes of Vector Quantization Indices Using State Codebook
Chin-Chen Chang, Guei-Mei Chen, and Chia-Chen Lin
Page(s): 274-282
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In a memoryless vector quantization system, each image block is independently encoded as a
corresponding index and then an index table will be generated. In this paper, we propose two novel
schemes to compress the index table without introducing extra encoding distortion. Both our
schemes exploit the characteristic that the blocks of images are highly correlated to find the same
or similar ndex from the neighboring indices in the compression process. To increase the
compression, the principal component analysis (PCA) technique is also employed to sort the
codewords in the codebook for minimizing the difference of neighboring indices. In addition, our  
second scheme excludes the repetitive indices from the search path to further decrease the bit rate.
Simulation results show that our schemes are superior to SOC and traditional memoryless VQ on
the compression rate.

Index Terms
Vector quantization system, SOC, PCA