| 摘要 |
<p>A noise reduction circuit arrangement for video signals under low brightness condition has a high-pass filter (3A, 3B) which detects the level of a video signal to switch the amount of passage of a high-frequency band component in accordance with a magnitude of the level. The video signal, produced from an image pickup element, is supplied to a low-pass filter (2) and the high-pass filter. The high-frequency band component produced from the high-pass filter and changed in amplitude in accordance with the level of the video signal and a low-frequency band component produced from the low-pass filter are added at an adder (10) so as to effect aperture correction in principle. The high-frequency band to be added is so controlled. as to more decrease when the brightness of the video signal is low than when the brightness is not low.</p> |
