| 摘要 |
PURPOSE:To reproduce a half tone picture always excellent in picture quality by selecting the optimum dither matrix in accordance with the size of a dot shape recording a binary picture signal. CONSTITUTION:In case of a half tone picture, a selector 24 is controlled by a mode selecting signal 27 so as to select the threshold 25 of a dither matrix. A selector 22 selects a dot concentration type dither matrix 20 or a network type dither matrix 21 in accordance with the size of a recording dot shape. Consequently, the threshold of the matrix 20 or 21 is inputted to a digital converter 32 through the selectors 22, 24 and a multilevel picture signal is encoded to a binary signal. In a picture other than a half tone picture, the selector 24 is controlled by a mode selecting signal so as to select a fixed threshold 26 and the converter 32 converts a multilevel picture signal 31 into a binary signal on the basis of the selected fixed threshold 26.
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