Grass Valley Imagestore 750 v.2.0.1 - Manual (Page 83)

Imagestore 750 User Manual Front Panel Operations
Miranda Technologies Inc. Page 83
and uses this to “cut a hole” in the Background signal and the Fill is then
simply added to this.
An example of this is where the output of a signal generator requires high
quality keying. If a Full key was used it may cause a darkened border around
characters where the character edge on the Fill signal correlates with the
character edge on the Key signal and the resultant Fill signal after
multiplication would be parabolic.
Full keying is where the Fill signal needs to be multiplied by the Key signal
prior to being added to the modified Background signal. In this case, the Fill
has not already been cut by its key external to the Imagestore 750. Then the
Imagestore 750 cuts a hole in the Fill with the Key and then cuts a hole in the
Background with a computed (1-Key) signal. The cut Fill and cut
Background are then added together.