| 摘要 |
PURPOSE:To contrive to reduce the mixture of a component of chromakey back on a synthesized picture by using a NAM (non-additive mixing) circuit so as to synthesize an output signal of a color selection circuit and a signal being the result of retarding the output signal by a delay circuit and outputting a chromakey signal shaped from a shaping circuit. CONSTITUTION:A chrominance signal fed to input terminals 1, 2 is subjected to color selection by a color selection circuit 3 and the result is a signal expanding timewise the region representing chromakey back by a boundary expanding circuit 4. Then the expanded signal is shaped by a shaping circuit 5 and sent from an output terminal 6 as a chromakey signal. An output signal of the color selection circuit 3, that is, one of signals fed to an input terminal 11 of the boundary expanding circuit 4 via a delay circuit 12 and the other signal directly in this case are input signals to the NAM circuit 13. The output signal (c) from an output terminal 14 of the boundary expansion circuit 4 is converted into a signal having a wide region in the chromakey back and a chromakey signal with more excellent S/N and less flickering is obtained.
|
