EP0284108A2 — Video matte generator

USPTO Abstract

A matte generator for generating a video sig­nal representative of a matte having a uniform color, comprises an operator interface for gen­erating signals representing three independent variables which are sufficient to characterize a color. A processor receives the input signals and derives three numerical values from the input sig­nals and from calibration values provided to the processor, and a quadrature modulator receives a subcarrier signal and signals representing the three numerical values and generates an encoded video signal in response thereto. The encoded video signal and a calibration signal are applied to a calibration circuit for comparing the encoded video signal and the calibration signal and pro­viding an output signal representative of the re­lationship therebetween. The output signal of the calibration circuit is applied to the processor and is used to generate calibration values such that the encoded video signal is brought into predeter­mined relationship with the calibration signal.