Systems and methods that facilitate automatic convergence and geometry
alignment in projection systems such as a PTV. The automatic convergence
system (ACS) preferably includes a CCD camera mounted inside the PTV and
focused on the entire inside of a projection screen Fresnel lens.
Alternatively, the ACS may include a deployable reflective sheet,
preferably in the form of a roll up screen. In operation, signals from
the CCD camera corresponding to test patterns projected onto the Fresnel
lens or reflective sheet are analyzed and used to align, center or steer
raster patterns to compensate for convergence error at a particular
location. In a convergence mode, the video is blanked and then successive
monochrome video test patterns are projected on the screen. The images
captured by the CCD camera are used to memorize the location of landing
points of one color test pattern from one of the projection units and
then to align the other color patterns from the other projection units to
the same landing points as the first color pattern. In a geometry
alignment mode, the difference in brightness between an image striking
the Fresnel screen and the over scanned area of the PTV cabinet is used
to determine the border of the screen. This information is then used to
provide reference marks for all geometrical adjustments done
automatically using a similar process of successive test patterns and
analysis.