Grass Valley XtenDD v.4.2.4 - Manual (Page 214)

3. Menu Operation
3 – 67 Operating Instructions – Rev. 1 / 7.2002
Pressing the Auto button starts an automatic key adjustment to Blue. The picture
evaluation includes all those colors which are within an angle range of
"
30 o
around the primary color Blue. Within this range, blue with the highest intensity is
detected as key color. Key color and selectivity are thus adjusted.
If Sel Mask is enabled Sel Auto starts an automatic selectivity adjustment for both
areas inside and outside the mask.
The FGD Fade (foreground fade) key switches over the chroma key procedure.
Now, the cleaned key fill signal and the background signal are faded in one fading
operation by the key control signal.
In the area of the key color, only chrominance is subtractively removed, luminance
is retained. However, this will impair some advantages of the DynaChrom
t proce-
dure (good reproduction of details and transparency).
For optimal adaptation of cross fadings on edges or for optimization in case of
transparencies between foreground and background, the luminance value can be
adjusted in the area of the key color.
Adjustment is made with the L-Offset control in the ChromaKey menu.
This mode is recommended when object edges will show unnatural, extreme brigh-
tenings in details and transparency areas in case of too intense CLEAN-UP adjust-
ment, or extreme darkenings in case of too intense DENSITY adjustment.
This FGD Fade mode may also be selected for improving the clean-up effect. It is
required for eliminating noise and shadows and for adapting original backgrounds
to key-influenced backgrounds with the DVE.
Note: Please note that Foreground Fade is enabled automatically - without
special indication at the control panel - in the following modes:
•
Chroma Key Invert
•
Chroma Key with Border
•
not Self Key.
Before adjusting Chroma Key, you should try to create optimum conditions
on the picture source side to ensure low interference, for example by an
evenly lit blue wall of maximum size and little camera post-amplification.
Selective mask is available with the two chromakey modes DynaChrome
t
and FG
Fade. Thus, it is possible to select inside a mask area another selectivity than out-
side the mask. This means, when – due to color conflicts within the picture – no
compromise can be found between the density of foreground objects of a certain
color and the freedom from fringes of other objects with the same color, the relevant
objects can be separated by the mask.
The separation lines remain invisible in the areas of the background. With correct
adjustment, they also remain invisible in the areas of the foreground. Only colors
at the object edges can be then affected.
Auto
Sel Auto
FGD Fade
Sel Mask