Digital chromakey apparatus
First Claim
1. A digital chromakey apparatus for use in providing a single display of selected portions of first and second digital video signals, comprising means for generating a digital key signal in response to specified chroma information contained in said first digital video signal, means for mixing said first digital video signal with said second digital video signal in response to said generated digital key signal and, means for adjusting said digital key signal so as to selectively control the location in time of a leading edge and trailing edge of said digital key signal, said means for adjusting including means for detecting said leading edge and trailing edge of said digital key signal and level control means for selectively altering amplitude levels of said leading edge and trailing edge of said generated key signal in response to external commands of expansion or compression.
1 Assignment
0 Petitions
Accused Products
Abstract
In a digital chromakey apparatus, a digital key signal is generated in response to specified chroma information of first digital video signal designating a foreground scene and the first digital video signal is switched into second digital video signal designating a background scene in accordance with level of the digital key signal. According to this invention, the digital key signal is adjusted or compensated in level at portions of leading and trailing edges thereof so as to expand or compress the area of chromakey.
29 Citations
13 Claims
- 1. A digital chromakey apparatus for use in providing a single display of selected portions of first and second digital video signals, comprising means for generating a digital key signal in response to specified chroma information contained in said first digital video signal, means for mixing said first digital video signal with said second digital video signal in response to said generated digital key signal and, means for adjusting said digital key signal so as to selectively control the location in time of a leading edge and trailing edge of said digital key signal, said means for adjusting including means for detecting said leading edge and trailing edge of said digital key signal and level control means for selectively altering amplitude levels of said leading edge and trailing edge of said generated key signal in response to external commands of expansion or compression.
-
8. Apparatus for use in providing a single color video display of selected portions of a foreground color video signal and a background color video signal, comprising:
-
means for producing a digital key signal defining an area of a video display occupied by said foreground color video signal in respone to selected chroma information contained in said foreground color video signal and including back color data generator means receiving said foreground video signal for producing a back color data signal, and means for comparing said back color data signal and said foreground video signal and providing said digital key signal; key signal processing means for processing said digital key signal to produce a waveform-shaped digital key signal; color canceller means receiving said waveform-shaped digital key signal and said foreground color video signal for producing a color cancelled video signal in which said back color data signal is fed to said color canceller means for eliminating the back color video data from said foreground color video signal in response to said waveform-shaped digital key signal; and mixer means combining said color cancelled video signal and said background video signal for producing a mixed color video signal to form said signal video display. - View Dependent Claims (9, 10, 11, 12, 13)
-
Specification