PURPOSE:To attain data compression for consecutive white or black level information with a high frequency of occurrence in a text picture especially with a high compression rate by setting a color flag set to 0 into 1 or set to 1 into 0 when bits expressing gradation are all 1. CONSTITUTION:A most significant bit is selected as a color flag, and when the color flag is set to 0, a black/white picture is discriminated and when the color flag is set to 1, a color picture is discriminated and other plural bits are used to express the gradation in this compression system. A picture data from an input I/F 104 is compressed by a data compressor 105. When the gradation bits are all 1, the color flag set to 0 or 1 is revised into 1 or 0, and a high compression rate is obtained by the run length coding or the prediction encoding system especially in a text picture.
SERIAL PICTURE DATA COMPRESSION SYSTEM HAVING COLOR INFORMATION