| 摘要 |
PURPOSE:To improve picture quality and to eliminate a diaphragm by providing a detection means detecting the brightness of an observation object part and an adjustment means adjusting charge storage time against the picture by each color in a solid-state image pickup element based on the sensitivity by each color of the solid-state image pickup element and the brightness of the observation object part. CONSTITUTION:The charge storage time of a CCD 16 is changed so as to obtain required exposure based on the difference of a luminance signal VY in proportion to the accuracy of the observation object part and a luminance reference level Vref. For example, the output of a differential amplifier 68 is enlarged when the luminance signal VY becomes larger than the reference level Vref (when the observation object part is too light), and the output levels of respective amplifiers 64, 64 and 66 are raised. As the result, an AND gate 28A passes through an unnecessary charge sweeping pulse so that the charge storage time of the CCD 16 can be shortened. On the other hand, the luminance signal VY becomes small when the observation object part gets dark, and the optimum luminance level can be obtained while the charge storage time gets longer contrary to the above-mentioned case.
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