Chroma keyer with correction for background defects
First Claim
1. A circuit for generating a control signal for correcting background defects in a video signal having a color background portion and a foreground object portion comprising:
- means for generating an initial chroma control signal from a chrominance component of the video signal;
means for modifying the initial chroma control signal as a function of the magnitude of a chrominance component of a reference signal representing the color background portion without the foreground object portion to produce a chroma key control signal; and
means for combining the chroma key control signal with the reference signal to generate the control signal.
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Abstract
A chroma keyer with correction for background defects generates a control signal that does not include variations associated with the background defects. The chroma magnitude of a reference signal that represents a chroma key set with a color background scene without a foreground object is used as a divisor for a hue select signal generated by a hue selector from a chrominance component of an input signal that represents the chroma key set with the foreground object to produce a chroma key control signal. The chroma key control signal is combined with the reference signal to produce a control signal for background suppression. The chroma key control signal also is input to a key circuit to produce a key signal for shaping a new background scene. The reference signal also may be combined with a uniform color signal from a reference matte generator to produce an error signal that is combined with the chroma key control signal to produce the control signal for correction of the background defects in the input signal.
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Citations
14 Claims
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1. A circuit for generating a control signal for correcting background defects in a video signal having a color background portion and a foreground object portion comprising:
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means for generating an initial chroma control signal from a chrominance component of the video signal; means for modifying the initial chroma control signal as a function of the magnitude of a chrominance component of a reference signal representing the color background portion without the foreground object portion to produce a chroma key control signal; and means for combining the chroma key control signal with the reference signal to generate the control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification