| 摘要 |
<p>PURPOSE:To reserve the information of a detailed part of an image in a state that a halftone reproducibility remains maintained as it is, by detecting whether density information and edge information exist or not by a small block unit, from a binary original image, and switching adaptively a variable power processing method in accordance with the presence and absence of the edge information. CONSTITUTION:As for an image whose density variation is flat, the deterioration of a halftone expressiveness is related to the deterioration of the picture quality as a visual sense, and on the contrary, as for an image containing many edge information, the deterioration of a resolving power is related to the deterioration of the picture quality. Accordingly, by switching these two variable power methods in accordance with the quantity of edge information, the deterioration of the picture quality is reduced. A binary data outputted from a dither processing circuit 2 and a line buffer 7 is inputted to an edge information detecting circuit 8. An area deciding circuit 9 adds the edge information of a 4-line portion, and outputs a select signal 1, when the edge information exceeds 4 picture elements at every 4X4 areas. The result of decision outputted from the area deciding circuit 9 is inputted to a selector 6, and uses as a select signal for switching adaptively variable power images of 2 systems from a dither circuit 3 and a variable power circuit 5.</p> |
