| 摘要 |
PURPOSE:To improve color reproducibility automatically by detecting the level of each color video signal obtained by photographing of a prescribed color chart and detecting difference from the ideal value of video signals of each color under this state stored beforehand, and calculating a controlling signal that makes the differential signal an optimum value. CONSTITUTION:Signals of each color R-B obtained by photographing of a prescribed color chart are gain controlled 4-6 and applied to color level detecting circuit 20-22 and level of each signal R-B is detected. Each detected level signal is inputted to the reference color signal comparator 30 of an arithmetic processing circuit 23 in which an ideal value at the time of photographing color chart is stored beforehand. Each signal level detected by the comparator 30 and reference level of stored ideal value are compared. The result of comparison is inputted to a microprocessor 31 and calculation to eliminate differential voltage of each color is performed. Controlling voltage is outputted from a matrix coefficient control voltage outputting circuit 32 to control gain controlling circuits 24-29, and color difference signals of differential amplifiers 7-9 are adjusted.
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