| 摘要 |
PURPOSE: To preserve a thin line and a void thin line in source pictures in reduced pictures and to reduce density change by selecting a thinning method corresponding to the characteristics of the source pictures. CONSTITUTION: A reduction circuit part 201 is provided with a function for switching simple thinning, OR thinning and AND' thinning corresponding to a truth table. Since printing is performed with the high density of the reduced pictures by the OR thinning and the printing is performed with the low density by the AND thinning, when the density of the source pictures is low and when it is required to preserve the thin line, the OR thinning is used. On the other hand, when the density of the source pictures is high and when it is required to preserve the void thin line, the AND thinning is used. Also, when it is not required to preserve the thin line or the void thin line in the case of color printing, the simple thinning is used. In this case, inputs S0 and S1 are the switching signals of the thinning method, the simple thinning is selected at the time of S1=0, the OR thinning is selected at the time of S1=1 and S0=0 and the AND thinning is selected at the time of S1=1 and S0=1. |
