Optimization adjustments – Tektronix Grass Valley 3000 User Manual
Page 177
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Chroma Keying Operations
Optimization Adjustments
It is now time to optimize the keyer setups.
1.
If you are using an external analog key source such as RGB
from a camera, verify that the input timing is correct.
Temporarily turn on
FGD RESHAPE
in the
CHR KEY/
KEY ADJUST
, and look for unequal black lines at the left and
right sides of the foreground object.
Refer to “System Timing” in Section 2, Installation and Service
manual for adjustment details if necessary.
2.
Turn
FGD RESHAPE
off.
3.
Optimize the
CLIP
and
GAIN
. Refer to
Manual Adjustment on
, but do not start from
scratch settings. Remember, adjust
CLIP
first, then
GAIN
.
4.
Optimize
SELECTIVITY
to obtain as much foreground as
possible looking closely at areas which contain some blue
fringing (for example, hair or glass). Observing the
SHOW KEY
display may help this with adjustment.
5.
Optimize
CHROMA
background suppression to eliminate the
color of the background. Too much suppression results in the
background taking on its complementary color. If a vector
monitor is available, the correct adjustment places the
background “dot” in the center of the display. The initial
adjustment usually produces the correct setting, but it is
important to verify it now.
6.
Evaluate the Key and make the following adjustments
depending on the amount of lighting variation visible in the
background. Large lighting variations make luminance
background suppression difficult or impossible without
darkening the foreground.
Decrease the
LUMA
background suppression (on the panel)
and observe the Key in the picture and the waveform monitor.
As suppression is decreased, the background begins to
lighten. If the background shading does not remain relatively