JPS6461169A - Halftone picture separation processor - Google Patents

Abstract

PURPOSE:To contrive the improvement of picture quality by using a deciding means so as to decide whether a split picture element block and a picture element block deviated therefrom are respectively in a binary picture area or a gradation picture area and applying picture processing to an input picture in response to the result of decision, thereby preventing the occurrence of raggedness in a character or a thin line part. CONSTITUTION:Block area deciding circuits 37, 38 decide whether a designated block is in a binary picture area or in a gradation picture area. The deciding circuit 38 applies the decision of a block deviated from the block decided by a block area deciding circuit 37. When the block is decided to be a binary picture area, '1' is outputted. A threshold level switching circuit 40 selects the threshold level of a binary picture threshold level generating circuit 41 when the output of an OR gate 39 is '1' and selects the threshold level of a dither picture threshold level generating circuit 42 when '0'. A binarization circuit 43 uses a threshold level selected by a threshold level switching circuit 40 to output a picture signal stored in a picture memory 36 as a binarization picture signal. Thus, the binarization processing suitable for respective pictures is applied and the resolution and gradation of the original where characters and photographs exist in mixture are reproduced in an excellent way.