Video camera, printer apparatus and method of controlling same, and apparatus and method for detecting print inhibit signal

摘要

The levels of video signals obtained by photography at a relatively high shutter speed and photography at an ordinary shutter speed are made approximately equal at all times, irrespective of any change in the characteristics of an AGC. Photography performed at a relatively high shutter speed of one time in a plurality of fields and photography is performed at an ordinary speed at other times is repeated periodically. One field of a luminance signal obtained by photography at the relatively high shutter speed is integrated by a first integrating circuit, and one field of the luminance signal obtained by photography at the ordinary shutter speed is integrated by a second integrating circuit, wherein the luminance signals represent contiguous images. A signal representing the difference between these integrated values is produced by a difference detecting circuit. The difference signal serves as a gain correction signal. The gain correction signal is added to a gain control signal, and the resulting signal is applied to the AGC. The gain control signal of the AGC is corrected by the gain correction signal so that the average level of the video signal resulting from photography at the relatively high shutter speed and the average level of the video signal resulting from photography at the ordinary shutter speed become approximately equal in the AGC.