| 摘要 |
PROBLEM TO BE SOLVED: To change the shutter speed to low when AGC voltage becomes maximum without operation of a BLC(back light compensation) function. SOLUTION: Sampling and gain control or the like are performed to a video signal from a CCD 1 at an S/H and AGC circuit 2, the video signal is converted into a digital signal at an A/D converting part 3, it is formed as an analog Y/C signal by performing a gamma correction or the like to it at a DSP(digital signal processor) and D/A circuit 4, formed as a composite signal and outputted at an MTX circuit 5. A BLC control signal from a DSP circuit and the AGC voltage are monitored by a microcomputer 9, when no BLC function is operated (maximum voltage) and the AGC voltage is maximum, luminance data is taken out by communicating with the DSP circuit, when brightness is judged to be in short, an electronic shutter control signal to lower the shutter speed is outputted from the DSP circuit, an equivalent signal is generated by a timing generator 12 and the shutter speed is switched to low by a shutter control part 13.
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