| 摘要 |
PROBLEM TO BE SOLVED: To provide a dither mask generating system to generate a dither mask which does not cause moire or rosetta patterns, can transfer ink satisfactorily, and keeps the consistent gray level characteristic in order to obtain high definition half-tone images of high quality, a produced dither mask, half-tone images obtained by using the dither mask, and printed matters. SOLUTION: This dither mask producing system comprises a mask storage means for storing a dither mask, a block division means for dividing the dither mask into blocks, a random number generating means for allocating random numbers to pixels in those blocks, an evaluation function value computing means for computing the variations in the evaluation function values before and after the exchange of two pixel values that were selected from each block by the random numbers, an exchange determination means for deciding whether the exchange should be performed based on the differences, a pixel value exchange means for exchanging the pixel values based on the result by the exchange determination means, and a process repeating means for repeating those processes.
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