| 摘要 |
PURPOSE:To obtain a reduced picture without spoiling the property of half-tones by outputting reduced picture element blocks after making a black/white decision by using a dither matrix generated by generating random numbers for every two- dimensional block. CONSTITUTION:A reduced block area dividing part 102 divides binary black/ white digitized picture information in a reduction objective rectangle in video memory 101 into reduction processing unit blocks. A reduction picture element point determining circuit part 103 calculates change point position information in a processing unit block after reduction simultaneously with the block division. Then, the picture element level at a change point is calculated by a calculating circuit part 104 for reduction picture element point picture element level and the two-dimensional picture element level matrix in this processing unit block is outputted. This output is supplied to a reduction picture element point dither processing circuit part 105, which makes a black/white decision by using the dither matrix as a threshold value to output the result as output picture information to reduced dither picture memory 106.
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