Luma Keying; Luma Key Installation - Datavideo DVK­100 Mk II Instruction Manual

Luma Keying
As well as being a Chroma Keyer the DVK­100 can also be used as a Luma Keyer. A Luma Keyer can key
out luminance values. In simple terms you can remove either the white end of the grey scale, or the black
end of the grey scale. If for example you have an image on a white or black background it is possible to use
Luma Keying to superimpose the image over a video background. Here are two examples that show some of
the possibilities.
Foreground Image with Black Matte Finished Image with Background Video
showing through the Black Matte Area
Text on a white background Text superimposed over background video
by using Luma Keying
Luma Key Installation
The following installation diagram offers a number of possibilities. Please bear in mind that, despite their
name, CAM­1 and CAM­2 do not necessarily have to be connected to Cameras, they are merely the
Foreground video inputs.
The CAM­1 input has a computer connected to it. This could be connected via a Scan Converter (also known
as a Down Converter), or the DV Output could be connected via a Digital to Analogue Converter such as the
Datavideo DAC­100 (see page 30 for more details). Using the DV Output you could use footage directly from
an NLE system, or you could run PowerPoint pages via the Datavideo PPT­100 software (see page 30 for
more details).
The CAM­2 input has a DVD Player / VCR playing pre­recorded video with matte effects.
The Background Video could be live video from a camera, or pre­recorded footage from a DVD Player or
VCR.
The output has been illustrated running to a DVD Recorder / VCR, but it could just as easily be going to a
distribution amplifier supplying a number of live screens, or a DAC­100 supplying a stream to a PC for a live
webcast.
The connections for these products are the same as those used in our Chroma Keying Installation (see page
12).
Example Luma Key Installation Diagram.
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