AAXA Technologies M4 - Manual (Page 41)

Keystone Adjustments
Digital Keystone Adjustments
By adding a special, selectable, algorithm to the scaling, some new projectors
are able to alter the image before it reaches the projection lens. The result is a
squared image, even at an angle.
What is Keystoning?
“Keystoning” occurs when a projector is aligned non-perpendicularly to a screen,
or when the projection screen has an angled surface. The image that results
from one of these misalignments will look trapezoidal rather than square.
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