Reducing computation for vector quantization by using bit-mapped look-up table

Vector quantization (VQ) is an elementary technique for image compression. However, searching for the nearest codeword in a codebook is time-consuming. In this work, we propose an adaptive scheme "bit-mapped look-up table" (BLUT) which can prune codewords rapidly. This new scheme uses positional information to represent the geometric relation within codewords. Accordingly, the lookup procedure could refer the information to sift candidate codewords easily. This scheme might also cooperate with existing schemes to speed-up searching. Simulation results confirm this effectiveness.