| 摘要 |
PURPOSE:To obtain stable color reproduction even to a wide variety of change of color temperature of a light source by providing an operational amplifier forming a luminance signal comprising red, green and blue signals of a prescribed ratio to eliminate the error component attended with the color temperature change of the luminance signal. CONSTITUTION:The red signal is fed to an input terminal 1, the blue signal is fed to an input terminal 3 and the luminance signal Y is fed to an input terminal 2 respectively. Variable gain control amplifiers 7, 8 are formed by a white balance circuit and the gain is controlled by a control voltage fed respectively from control terminals 9, 10 to attain white balance adjustment of the supplied red and blue signals R and B and correct the level change attended with the change in color temperature. An input/output red signal of a variable gain amplifier 7 and an input/output blue signal of a variable gain amplifier 8 are fed to an operational amplifier 11 and attain the color temperature correction of the luminance signal through the operation processing. The corrected red and blue signals are obtained at output terminals 4, 6 respectively and the corrected luminance signal is obtained at an output terminal 5. |
