JPS612230B

PURPOSE:To shorten the graphic process time by avoiding the mixture of the code showing the unnecessary neutral tints in case the binary graphic, for example, is encoded. CONSTITUTION:In case the color graphic, for example, is encoded as the multi- value graphic, the graphic is divided into R, G and B components with n-bit applied to each component. When the graphic of P-bit smaller than n-bit such as the binary white/black graphic is encoded under these conditions, all of R, G and B components have a change in the color component. In this connection, the quantizing bit of each component is coincided with the highest-rank bit when the highest-rank bits of all components have some change. Otherwise, a bit conversion is given so that all color component bits are coincided with the highest-rank bit Q2 of G component for instance. As a result, the conventional same encoding system can be applied even though the input graphic is binary or multi-value. Furthermore, the undesired code of neutral tints, for example, can be prevented from being mixed into the code of the binary graphic.