| 摘要 |
PURPOSE:To enlarge and reduce a binarization picture without producing a moire fringe even if the binarization picture has a periodical structure and to make a gradation processing easy by converting the number of picture elements based upon a gradation curve and deciding the density level of each block from the number of converted picture elements. CONSTITUTION:The binarization picture is divided into blocks of appropriate sizes and then the gradation processing is made after counting the number of black picture elements in every block. For example, the number of original black picture elements shown in figure (b) is converted to that of conversion black picture elements shown in figure (c) by using the gradation curve (a). Thus, the density level of every block is decided by the number of conversion black picture elements and the first density matrix pattern is obtained. After the first density matrix pattern is obtained, the second density matrix pattern sizing in proportion to a multiplying facter of an enlargement or reduction is obtained in every block and then the enlarged or reduced scanning is obtained in a block order.
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