| 摘要 |
PURPOSE:To make it possible to shadow a video signal matching with a base signal by inserting a color signal by extracting a shadow in an input signal and then by gating the video signal. CONSTITUTION:Video signal 11 is input to shadow generating circuit 101, which detects the level of its shadow to generate shadow signal 123. This signal 123 in supplied to key linear gate circuits 103A and 103B to gate a control signald from key forming circuit 3A. Further, the outputs of circuits 103A and 103B differ is polarity from each other. Then, subcarrier 121 is input to color generating circuit 102, which outputs color signal 122. Gain control 1C controls signal 122 by signal 123 to extract the part of the shadow, which is output to adder circuit 4C. Circuit 4C sums the outputs of gain control elements 1A-1C to output color shadow chroma-key effect signal 13. Consequently, signal 13 is shadowed corresponding to signal 11. |
