A Novel Approach of Reordering Color Palette for Indexed Image Compression

The compression efficiency of an indexed image depends on the palette ordering. However, obtaining an optimal palette ordering is not an easy task, and approximate solutions are usually sought in practice. Among the available methods, the pairwise merging technique proposed by Memon is the best in terms of compression efficiency. However, this method needs extensive computations. In this letter, a novel algorithm is presented to find an approximate solution of the palette reordering problem. Combined with Pinho´s method, our approach is better than the pairwise merging technique in terms of compression efficiency and computing time