METHOD FOR ESTIMATING HALFTONE PICTURE OF BINARY PICTURE

摘要

PURPOSE:To estimate satisfactorily an original halftone picture from a binary picture by comparing the binary picture within each opening with the picture binary coded again by means of the value estimated based on the ratio between the white and black areas in the opening and defining the estimated value of the opening obtained when the coincidence is obtained between both pictures as the estimated value of the halftone picture. CONSTITUTION:Various types of openings G F E D C B A are set within a binary picture consisting of white and black areas for each picture element of the halftone picture to be estimated. Then the estimated value is obtained based on the binary picture in each opening and the ratio between the white and black areas in the corresponding opening. Based on this estimated value, the binary picture of each opening is compared with the picture binary coded again by a dither matrix corresponding to the size of the corresponding opening. Then the estimated value of the opening obtained when the coincidence is obtained between both binary pictures is defined as the estimated value of the halftone picture of the corresponding picture element. In such a way, an excellent picture is obtained.