| 摘要 |
PURPOSE: To eliminate a troublesome and visually unpleasant archifact due to a spurious signal that is visible as a hallow or a shade in a resulting image affected by a black background in the case of keying a foreground image to the background image. CONSTITUTION: First image data V denote keyed image including a 1st object F that is keyed on a part of a 1st background B according to keying data K. Second image data Bg denotes a background. The 2nd image Bg are weighted by respective control dataαrelating to the keying data K, combined with the 1st image and an output of R=V+Bg(1-α) is obtained, where V=F.K +B(1-K). In the case of B=0, a relation of R=FK+Bg(1-K) is obtained by substituting V=F.K to R=V+Bg(1-α). Then the result R outputted from an external keyer circuit indicates the foreground F keyed to the external background Bg without the effect from the original background B.
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