Graphics Programs Reference
In-Depth Information
The following screenshot shows the luminance of the same image using three differ-
ent modes of the
Separate YCbCrA
node:
It can be observed that the luminance displayed in all these models is not the same
since the weightage of 100 percent for each channel in RGB is different in each mod-
el. So, the model to be chosen depends on the requirement.
•
Y
in YUVA is the same as
Y
in YCbCrA in the
Jpeg
mode
• UV and CbCr are chrominance components that provide color information
After having a good understanding of luminance and the different models available,
an apt model can be chosen as a starting point in keying, where the color ranges to
be keyed are close to blacks or whites in a specific color model.
Inspecting a green/blue screen footage
The success of keying green/blue screen footage depends on the following factors.
These have to be inspected before proceeding to keying.
• The color to be keyed should have consistent lighting
• The subjects should be far enough from the green/blue screen, to avoid color
spill
• The subjects should be lit properly
• The footage should be uncompressed
