High Quality Montage Pictures by a New Color Killer Soft Chromakey System

A new technique for producing high quality montage chromakey pictures which were not obtainable by the conventional chromakey method has been developed by NHK. In early chromakey methods, gating signals with steep rise and fall times were shaped from the chromakey blue signal. Frequently the borderlines of the pictures produced were very unnatural. In later systems, gating signals with gentle rise and fall times are obtained from the chromakey blue signal, avoiding any clipping or stretching procedures. These gating signals control the level of the foreground key camera video signal and the level of the background video signal to be combined with it, so that the borderline of the two pictures will look more natural. In addition, a blue color killer circuit is provided, in order to eliminate the blue border between the two pictures, caused by the key camera signal. In the new technique, the color killer circuitry operates on the encoded signal rather than on the RGB signals normally used for the purpose. Furthermore, this new blue color killer circuit can be used as a color converter, not only for the blue color but also for other colors, to obtain special color effects. Because the operation is on an encoded signal, it is much easier to integrate into an existing studio complex. Some of the results are illustrated.

Print ISSN

0036-1682

Published

1981-02

Content type

Information

DOI

10.5594/J01500