Backing color and luminance nonuniformity compensation for linear image compositing
First Claim
1. In a system for generating a foreground video signal, wherein said foreground video signal includes at least a red signal, a blue signal and a green signal, each having an actual color value, said signals generated by scanning a colored backing, and said system includes control logic means for generating a control signal for controlling the compositing of said foreground signal and a background signal, said control signal being formed from said foreground video signal, the improvement comprising:
- means for generating for each of said red, blue and green signals, an error correction signal formed by taking the quotient of a predetermined color value and the actual color value.
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Accused Products
Abstract
A linear image compositing system which corrects for nonuniform luminance and/or color of the colored backing without incurring the penalties of edge glow, edge darkening, loss of edge detail and other anomalies. A control signal is created directly proportional to the luminance of the colored backing and controls the level of the BG scene. Unless the control signal is corrected, the background scene will contain all the brightness and color variations occurring on the colored backing. Correction factors are developed by comparing the RGB video obtained from the backing before the subject is put in place, with the ideal values of RGB that would have been obtianed from a perfect backing. These correction factors correct the RGB video when the scene is scanned with the subject in place. The control signal, being zero in the subject area, may be used to inhibit the corrections in the subject area.
36 Citations
8 Claims
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1. In a system for generating a foreground video signal, wherein said foreground video signal includes at least a red signal, a blue signal and a green signal, each having an actual color value, said signals generated by scanning a colored backing, and said system includes control logic means for generating a control signal for controlling the compositing of said foreground signal and a background signal, said control signal being formed from said foreground video signal, the improvement comprising:
means for generating for each of said red, blue and green signals, an error correction signal formed by taking the quotient of a predetermined color value and the actual color value. - View Dependent Claims (2, 3, 4)
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5. In an electronic compositing method for compositing a foreground video signal and a background video signal, wherein said foreground video signal includes at least a red signal, a blue signal and a green signal, each having an actual color value, said signals generated by scanning a colored backing said method including the step of generating a control signal using said foreground signal for controlling the compositing of said foreground signal and said background signal, the improvement wherein said scanning comprises the step of:
generating (75-88) for each of said red, blue and green signals, an error correction signal formed by taking the quotient of a predetermined color value and the actual color value. - View Dependent Claims (6, 7, 8)
Specification