Browsing by Author "Lu, ZM"

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A tabu search based maximum descent algorithm for VQ codebook design
(2001-09-01)
Huang, HC
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Chu, SC
;
Pan, JS
;
Lu, ZM
;
電子工程學系及電子研究所
A maximum descent (MD) method has been proposed for vector quantization (VQ) codebook design. Compared with the traditional generalized Lloyd algorithm (GLA), the MD algorithm achieves better codebook performance with far less computation time. However, searching for the optimal partitioning hyperplane of a multidimensional cluster is a difficult problem in the MD algorithm. Three partition techniques have been proposed for the MD method in the literature. In this paper, a new partition technique based on the tabu search (TS) approach is presented for the MD algorithm. Experimental results show that the tabu search based MD algorithm can produce a better codebook than can the conventional MD algorithms.
Vector quantization based on genetic simulated annealing
(2001-07-01)
Huang, HC
;
Pan, JS
;
Lu, ZM
;
Sun, SH
;
Hang, HM
Genetic algorithm (GA) has been successfully applied to codebook design for vector quantization (VQ). However, most conventional GA-based codebook design methods need long runtime because candidate solutions must be fine tuned by LBG. In this paper, a partition-based GA is applied to codebook design, which is referred to as genetic vector quantization (GVQ). In addition, simulated annealing (SA) algorithm is also used in GVQ to get more promising results and the corresponding method is referred to as GSAVQ. Both GVQ and GSAVQ use the linear scaling technique during the calculation of objective functions and use special crossover and mutation operations in order to obtain better codebooks in much shorter CPU time. Experimental results show that both of them save more than 71-87% CPU time compared to LEG. For different codebook sizes, GVQ outperforms LEG by 1.1-2.1 dB in PSNR, and GSAVQ outperforms LBG by 1.2-2.2 dB in PSNR. In addition, GVQ and GSAVQ need a little longer CPU time than, the maximum decent (MD) algorithm, but they outperform MD by 0.2-0.5 dB in PSNR. (C) 2001 Elsevier Science B.V. All rights reserved.