Recursive computation method for fast encoding of vector quantization based on 2-pixel-merging sum pyramid data structure

In principle, a multi-resolution distortion computation method can completely reuse the obtained computation result that is already executed at a lower resolution level so that no waste to it will occur at all. This paper aims at improving the search efficiency of the previous work [Pan, Z., Kotani, K., Ohmi, T. 2004. An improved fast encoding algorithm for vector quantization using 2-pixel-merging sum pyramid data structure. Pattern Recognition Lett. 25 (3) 459] further by introducing a multi-resolution distortion computation method into multi-resolution distortion check method so that about half of its computational cost can be reduced mathematically. Experimental results confirmed the proposed method outperforms the previous works obviously.