| 摘要 |
The readjustment of the image contrast is effected by a processing circuit (12) of the video signal, provided with a contrast control terminal (21). Among the devices which automatically act on the contrast, the device for comparing the peak values of the video signal to a reference threshold (Vref) is also used for manual adjustment. The gain of the amplification of the video signal in the processing circuit is increased such that, for the majority of images, the peak values of the video signal reach the reference threshold (Vref), while a user control varies this reference threshold to effect the manual adjusting.
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