| 摘要 |
An image pickup apparatus having a light source for providing an illumination light; an endoscope including illumination fiber optics for transmitting the illumination light to a foreground subject, and image fiber optics for sensing an optical image of the subject and transmitting this image; a video circuit for converting the optical image into a video signal; and a feedback circuit for converting the video signal into a light source drive signal and for continuously feeding the light source drive signal back to continuously set the light source so that the video signal is maintained at a substantially constant prescribed level. The light source, illumination fiber, optics image fiber, optics video circuit and feedback circuit jointly constitute an automatic level control loop which is continuously actuated as to continuously set the video signal to the substantially constant prescribed level.
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