| 摘要 |
PURPOSE:To attain proper luminous amount adjustment in matching with both dark and bright visual field lighting by using a mean value of signals from an object to be detected as a control signal and using a maximum value respectively at bright visual field lighting and a dark visual field lighting so as to control the luminous amount of a light source. CONSTITUTION:A video signal from an image pickup tube 6 is transmitted to a switching circuit 22 via a TV camera control section 21, an aperture detector 16 detects whether the state is in the bright or the dark visual field state, the changeover circuits 22, 23 switch the signal and give the said video signal to a signal averaging circuit 24 or a signal peak hold circuit 25. The signal averaging circuit 24 averages the video signal at the bright visual field lighting, the signal peak hold circuit 25 obtains the maximum value of the video signal at the dark visual field lighting, and after they are amplified by an amplifier circuit 27, the result is fed to a control section 28 so as to adjust the luminous amount of the lighting light source 7.
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