| 摘要 |
PURPOSE:To enable highly accurate discrimination by making discrimination corresponding six kinds of number of picture elements data after ternary coding to the state of picture. CONSTITUTION:A ternary dither circuit 35 makes ternary coding of picture signals for each picture element using threshold level for 3X3 dither matrix. Picture signals 38 ternary coded by the ternary dither circuit 35 are supplied to a post dither process picture signal extracting circuit 39, and picture signals 440-448 are supplied respectively to a post dither process white counter circuit 45, a post dither process gray counter circuit 46 and a post dither process black counter circuit 47, and number of picture elements corresponding to picture signals of white, gray and black after ternary coding is counted. A discriminating circuit 67 discriminates whether picture state discriminating area of a remarked picture element P0 is character picture or halftone picture basing on three kinds of signals i.e. white difference signal 66, gray difference signal 71 and black difference signal 74.
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