A Coding Method of Multicolored Images Using Dynamic Pattern Generator

Abstract

AbstractThe mosaic method and geometric method have been used for coding the multicolored image. This paper proposes a dynamic pattern generation method aiming at a more faithful image representation. In the proposed method, the color boundary is extracted from the original picture. The result is divided into smaller blocks, and the pattern code is generated for each block.A different set of patterns is defined according to the joining state of the color boundary to the adjacent already‐encoded blocks. By this scheme, a variety of patterns can be generated by a limited coding complexity. When patterns with high occurrence frequencies are encoded by 4 bit and those with low frequencies by 8 bit, approximately 9500 kinds of patterns can be provided. Approximately 90 percent of the actually appearing patterns belong to the patterns encoded by 4 bit, and the coding efficiency is improved.The color of the region surrounded by the color boundaries should be specified only for the case where the color cannot be determined from the joining relation from the adjacent blocks. Consequently, the color specification data occupies only 10 percent of the total code. Since a large number of patterns can be prepared, an image faithful to the original picture can be restored.