| 摘要 |
PURPOSE:To minimize the missing of tilt lines or thin lines by executing the processing to extract a median of change point address between a scanning line to be interleaved and its adjacent scanning line as to the subscanning direction. CONSTITUTION:In case of reducing the scanning line, a scanning line expansion/ intermediate point extraction circuit 33 applies the processing of taking a median of change point addresses corresponding between the scanning lie to be interleaved and the scanning processed just precedingly with respect to the subscanning direction. Moreover, the change point address to be processed is subject to integral number processing while being multiplied with magnification/reduction factor by a change point address calculation circuit 34, and the result is given to a change point address correction circuit 35 of the next stage, where the processing preserving black or white level isolated point is applied so as to prevent that they are not missing. Thus, the missing of lateral thin lines or tilt lines due to interleaving is minimized and the ratio of black and white level data of the scanning line to be interleaved and the scanning line to be processed just precedingly is made constant even at reduction. |
