CODING METHOD FOR STILL NATURAL PICTURE WITH MIXED EXISTENCE OF BINARY PICTURE

摘要

PURPOSE:To realize coding by which a white/black gradation picture and a color picture including a character area are less deteriorated by coding the character area through the use of the binary picture coding system and coding the remaining picture with the natural picture coding system. CONSTITUTION:A character area discrimination circuit 9 analyzes a received picture S' and gives a command to a picture element binarizing circuit 2 so as to apply binarizing processing to a picture element block only including a character. A binary picture coder 5 codes a picture B received from the circuit 2. A coder 9 codes mean values Sh, S1 of the picture received from the circuit 2 for each block, and a natural picture coder 7 codes a picture D received from a differential picture generating circuit 4. A signal output circuit 8 receives data Bc, Shc, S1c, Dc coded from the coders 5-7 and outputs a signal in a specific format. Thus, it is possible to realize the coding causing less deterioration of a white/black gradation picture and a color picture including the character area.