An Improved Codeword Search Algorithm Based on Hadamard Transform

A fast algorithm of VQ codeword search is proposed. A fast codeword search is performed in the Hadamard transform (HT) domain. The process to get the best matched codeword is as follows: First, some number of codewords in which Chebyshev distortion is the minimum are selected from the codebook according to the Chebyshev distortion measure; second, the best matched codeword will be gained from above codewords based on the PDS algorithm. The simulation result and theory analysis indicate that the codeword searching time in the algorithm has been reduced greatly on the precondition of good performance and visual effect.