| 摘要 |
PURPOSE:To obtain a chroma-key device which prevents erroneous composition of an achromatic color area by detecting the distance of a foreground color video signal from the position of an achromatic color on color coordinates, and correcting the level of a key signal according to the distance. CONSTITUTION:Foreground color video data FG.VID and background color video data BG.VID applied to an interface 1 are adjusted to proper phases by a timing signal TRS and outputted. The data FG.VID is applied to a correcting circuit 3 to correct the level of color difference data on each sample according to the distance from the origin (achromatic color) of each sample of the data FG.VID on the color coordinates. The level-corrected signal is compared with a reference point corresponding to a back color, sample by sample, by a key signal generating circuit 4 to generate a key signal with a specific level. |
