| 摘要 |
PURPOSE:To attain an accurate white balancing even in the case of an object having many specified colors by generating a specified chrominance signal from plural color difference signals and executing the white balance adjustment by controlling the gain of a color difference signal in such a prescribed relation that the means value level of the specified chrominance signal goes to zero. CONSTITUTION:Color difference signals R-Y, B-Y are inputted to an encoder 10 and an I-signal generation circuit 12 which constitute a white balance circuit 11. The circuit 12 mixes the color difference signals R-Y, B-Y, and generates an I-signal which is the specified chrominance signal. The I-signal is inputted to a means value circuit 13, the means value level of the I-signal is compared with a reference level(zero level) in a comparator 14 and a signal corresponding to the deviation detected in said comparison is inputted to a function generator 15 as a color temperature control signal L. The generator 15 generates gain control signal Sr, Sb based on the color temperature control signal L, and supplies them to an R-signal circuit 6 and a B-signal circuit 7 to respectively control their gains 6, 7; thus the levels of the color difference signals R-Y, B-Y are changed to adjust the white balance so that the mean value level of I-signals goes to zero.
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