| 摘要 |
PURPOSE:To record a halftone picture including line drawing at high reproducibility by making halftone recording of both line drawing part and continuous drawing part by different intermediate modulating systems. CONSTITUTION:When a controlling section 6 outputs a line select signal to a picture data memory section 1 and sends a reading signal phis once, watched picture elements and peripheral picture element data are stored in shift register 11-13 of a line drawing detecting section 2. Subtracting circuits 14-17 calculate difference between picture data of each peripheral picture element and watched picture element, i.e. density, gradient. Comparators 18-21 compare the density gradient data with a reference value, and decides whether inputted data is line drawing or continuous drawing. When the result of decision of the line drawing detecting section 2 is continuous drawing, the halftone modulating section 3 makes halftone modulation by density pattern dither process. In the case of line drawing, halftone modulation is made only by binary density pattern of small matrix.
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