| 摘要 |
PURPOSE:To obtain nearly uniform sense of sharpness extending all over a picture frame by providing a switching means, which changes the frequency characteristic of a luminance signal for every prescribed range in an image pickup picture frame. CONSTITUTION:The luminance signal from a CCD is impressed to a terminal (a), and a switching pulse PX is sent to a characteristic switch circuit 14 from a switching position set circuit 13, only during the period corresponding to the right lower part of the picture frame, shown in a figure, while being synchronizing with the read-out timing of a CCD drive circuit 12. The circuit 14 leads the luminance signal to a high frequency band emphasizing circuit 11, by connecting the terminal (a) to (c), and (c') to (d) while the pulse PX is impressed. For a period, during which the pulse PX is not sent, the terminal (a) is connected to (b), and the terminal (b') to (d). Therefore, the frequency characteristic C after inserting the circuit 11 comes nearly equal to the frequency characteristic of the left upper part of the picture frame, and the curvature of an image field or the unsymmetric blur of an image pickup lens can be compensated.
|
