Sony MVS-6000 User Manual page 153

Chroma key window
You can adjust the range over which the key signal is determined as matching
the specified hue. When this adjustment is off the default ranges are used.
Chroma keying generates a key signal based on a particular color (reference
color) in the foreground (typically a plain blue background), and the "window"
refers to the range of colors which are regarded as matching this specified
reference color to create the key signal.
As seen on a vectorscope (that is, in the hue-saturation color space), the range
for this matching corresponds to a truncated sector. This range is specified by
two parameters: the "Angle" parameter, which determines the range of the hue
parameter, and the "Crop" parameter, which determines the degree of
truncation (see the following figure).
a)
Crop
Range of colors remaining
as foreground
a) The Crop and Angle values do not change even if
you use the auto chroma key function.
Y balance
In normal chroma keying, the key signal is based on the chrominance
component only, and all elements of the foreground with the same hue are
replaced by the background. Using the Y balance function, you can specify a
luminance level range within which the key is active, and replace the specified
part by the background.
You can use the Y balance function independently on the key signal for the
composition and the key signal for the color cancel function. When applied to
the key signal for the composition, this produces the foreground with the color
cancel effect applied. This can therefore be used to provide an impression of
smoke, for example.
a)
Angle
Range of colors creating the key signal
(to be replaced by background signal)
Window adjustment
Key Setting Operations Using Menus
Reference color
specified by Hue
setting
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