| 摘要 |
If the subject pixel density I is the minimum density (0), the input conversion portion H1 controls the output conversion portion H4 to output a level of OFF. If the subject pixel density I is the maximum density (255), the input conversion portion H1 controls the output conversion portion H4 to output the other level of ON. The input conversion portion H1 outputs the imaginary density A of one (1) to the input modification portion H2 if the subject pixel density I is the minimum density of zero (0). The input conversion portion H1 outputs the other imaginary density B of 254 to the input modification portion H2 if the subject pixel density I is the maximum density of 255. The conversion portion H3 compares, with the threshold value, a modified value I' supplied from the input modification portion H2. Even in the uniform density region having the density of zero (0) or 255, the comparison judgment attained by the conversion portion H3 will frequently change. The calculation process attained by the binary error generating portion H5 will frequently switch between two types of calculation processes (2) and (3). Uniformity in conversion errors distributed from the error distributing portion H6 to the error storing portion H7 is disturbed. Pixels will be turned On and OFF irregularly, thereby preventing occurrence of undesirable textures.
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