| 摘要 |
PURPOSE:To perform color temperature compensation with high precision by inputting the output of an external sensor to the control input terminal of a color gain control circuit through a circuit which corrects the spectral characteristic of an image pickup device. CONSTITUTION:When an image of a white subject is picked up and the color temperature of a light source is varied, control characteristics of an R-ch gain control circuit 4 and a B-ch gain control circuit 5 are so determined as shown by solid lines in a graph so that white is represented with an NTSC output 11 obtained through the signal processing of the camera. On the other hand, signals outputted from the external light sensor 12 through an inverting amplifier 13 and a noninverting amplifier 14 are not coincident with each other as shown by broken lines because of a difference in the spectral characteristic between the image pickup device 1 and sensor 12. The characteristic shown by the broken lines is corrected as shown by arrows through gamma circuits 15 and 16 and de- gamma circuits 17 and 18 to make a white balance adjustment in case of variation in the color temperature of the light source.
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