| 摘要 |
PURPOSE:To enable a picture drawing processing according to the density level of a display picture by detecting the maximum value and the minimum value of the density level of a picture element displayed on a CRT picture. CONSTITUTION:Picture data of one picture is transferred to a frame memory part 103 from a picture memory part 102. At this time, at the same time, in a peak hold circuit 107, the maximum value and the minimum value of the density level of the transferred picture data are held. The picture data of the one picture transferred to the frame memory part 103 is displayed on the CRT 106 through a D/A converter 105. In the case of the picture drawing processing, a main control part 101 reads the maximum value and the minimum value held in the peak hold circuit 107 and writes the data of white (maximum value) or black (minimum value) suitable for the display picture in the frame memory part 103. Thus, the picture drawing processing according to the density level of the display picture can be performed. |
