| 摘要 |
PURPOSE:To realize a more effective achromatic operation by forming an achromatic control signal from a chrominance signal in an achromatic circuit. CONSTITUTION:When the incident light of a color image pickup element (CCD1) has a high brightness part, any (or all) of the signals R-B supplied to transistors Q1-Q3 correspondingly thereto, for instance the level of the signal R is higher than a voltage Vk. Then, since the collector current of the transistor Q1 becomes larger, the collector current of the transistor Q5 becomes small, a voltage Vc is raised, the gain of an attenuator 11 becomes smaller than a standard value, and accordingly, a carrier chrominance signal Cm is attenuated and the achromatic operation is carried out. In such a case, especially, the level of the chrominance signals R-B before the white balance is corrected is detected and when either one thereof is saturated, the level of the carrier chrominance signal Cm is made small or 0. Thereby, even when the spectral characteristic of the CCD1 is different, or the color temperature of an object is changed, a proper achromatic operation can be performed.
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