Method of and arrangement for inserting a background signal into parts of a foreground signal fixed by a predetermined key color
First Claim
1. A method of inserting a background signal into parts of a foreground signal, said parts being fixed by a predetermined key color, said method including the step of deriving a control signal from the foreground signal, said control signal having a first value when the foreground signal represents a color in the region of the key color, and a second value when the foreground signal represents a different color, and in which the control signal has a transition range between the first and the second values, characterized in that said method further comprises the steps forming a difference, influenced by the control signal, between a vector of the background signal and a vector of a signal representing the key color, and vectorially adding said difference to the foreground signal.
2 Assignments
0 Petitions
Accused Products
Abstract
In a method of and an arrangement for inserting a background signal into parts of a foreground signal fixed by a predetermined key color, in which a control signal is derived from the foreground signal, this control signal assuming a first value when the foreground signal represents a color in the region of the key color and a second value when the foreground signal represents a different color, and in which the control signal has a transition range between the two values, a difference, influenced by the control signal, between the vector of the background signal and the vector of a signal representing the key color is vectorially added to the foreground signal.
36 Citations
7 Claims
- 1. A method of inserting a background signal into parts of a foreground signal, said parts being fixed by a predetermined key color, said method including the step of deriving a control signal from the foreground signal, said control signal having a first value when the foreground signal represents a color in the region of the key color, and a second value when the foreground signal represents a different color, and in which the control signal has a transition range between the first and the second values, characterized in that said method further comprises the steps forming a difference, influenced by the control signal, between a vector of the background signal and a vector of a signal representing the key color, and vectorially adding said difference to the foreground signal.
- 6. An arrangement for inserting a background signal into parts of a foreground signal, said parts being fixed by a predetermined key color, said arrangement including means for deriving a control signal from the foreground signal, said control signal having a first value when the foreground signal represents a color in the region of the key color, and a second value when the foreground signal represents a different color, and in which the control signal has a transition range between the first and the second values, characterized in that the arrangement comprises a first terminal for receiving chrominance components of the background signal and a second terminal for receiving chrominance components of the foreground signal, means for generating a signal (KC) representing the key color, a first adder having a first input coupled to the first terminal and a second input coupled to said signal generating means for adding the chrominance components of the background signal and an inverse of the signal (KC) representing the key color, a multiplier having a first input coupled to an output of the adder and a second input coupled to said means for deriving the control signal, and a second adder having a first input coupled to an output of the multiplier and a second input coupled to the second terminal carrying the chrominance components of the foreground signal, an output of the second adder carrying the output signal of the arrangement.
Specification