Classified vector quantisation (CVQ) of images is a vector quantisation-based coding method for preserving perceptual features while retaining simple vector quantiser distortion measures during codebook design and enc...
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Classified vector quantisation (CVQ) of images is a vector quantisation-based coding method for preserving perceptual features while retaining simple vector quantiser distortion measures during codebook design and encoding process. In the paper, a new algorithm for CVQ codebook design the ‘classified nearest neighbour clustering’ (CNNC) algorith, is presented. The CNNC algorithm is based on a classification process of small image blocks and on an agglomerative clustering algorithm, and is used to design simultaneously M codebooks for M different classes, defined for a CVQ system. The CNNC algorithm can be used with squared error and weighted squared error distortion measures employing one of two optimisation criteria which are presented and tested in the paper. In addition, fast search algorithm is presented aimed at reducing computational efforts encountered during codebook design. The CNNC algorithm is shown to provide a systematic and effective method for CVQ codebook design making CVQ more feasible and easy to implement.
This paper establishes a nonparametric test to compare estimators in Markov random fields. It is particularly useful when the behaviors of estimators are unknown. The proposed methodology is used to compare two estima...
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This paper establishes a nonparametric test to compare estimators in Markov random fields. It is particularly useful when the behaviors of estimators are unknown. The proposed methodology is used to compare two estimators, based on coding method and maximum pseudo-likelihood method, in the generalized Ising and auto-binomial texture models. Experiments show that the estimator based on maximum pseudo-likelihood is superior to the estimator based on coding method.
The sources of bit-rate variation in a conditional-replenishment videoconference coder were found experimentally to be due to the interaction between coding method and image content. The isolation of the components of...
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The sources of bit-rate variation in a conditional-replenishment videoconference coder were found experimentally to be due to the interaction between coding method and image content. The isolation of the components of variation and the effect on them of buffering and packetisation are reported.
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