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Once all the projectors have been aligned the next stage is to correct for and brightness non linearity
at the blends. This will adjust the brightness on ALL of the blends. By careful adjustment the user
should be able to find the correct value that removes any brightness rise or fall originally seen.
With the control slid to the right the overlay has a strong gradient applied to both images which will
result in a black edge in the centre of the image.
Moving the slider to the left overlaps the fade out between the projectors so that the black line disappears.
The Linearity Correction can also be applied using Gamma for Red, Blue and
Green channels independently.
This can be useful where your projectors have a different lamp life and they
fade to black in slightly different hues.
To adjust the various Gammas, a good way of seeing colour issues is to use a
Test Signal Generator to output colour bars then White Red, Green and Blue
colour fields making small adjustments until the best match across all colour
fields is obtained.
By clicking on the S-Curve button it is replaced with individual R G and B Gamma adjustments. The
user should change the input source from White to Red green or Blue. For each of these if they see a
projector outputting a different brightness then that output should be selected on the software
(make it the only one red) and then adjust the appropriate gamma to remove any visible difference.
When the Gamma correction has been completed a black source should be used
to adjust the 'Black Level Boost'. In very low light conditions it may be possible
to see a lighter area on the blended edges. By adjusting the 'Black Level Boost'
the level of brightness on each output is raised to match that at the joins.
The user should exit the Projector Alignment by clicking on the highlighted red
button and then press Take to store all the settings for the newly constructed
Layout.
Linearity Correction allows us to control the
overlap between the two projectors.
The overlap is defined in the overlap area in
the line-up graphic (not the amount of the
projectors).
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