Consider positioning the image from a data projector
on a portion of a spherical mirror. The light will be
scattered across a wide angle, the exact coverage depends
on the area of the mirror used, the curvature of the mirror,
and the relative position of the projector. It is relatively
straightforward to achieve 180 degrees horizontally and
140 degrees vertically
An image reflected in
this way and falling onto a surface such as a
hemispherical dome would appear quite distorted. It is
possible to predistort the image (from now on referred to
as warping) so that the result looks correct on the display
surface. Such a warped image for a particularmirror/projector/dome arrangement is shown in fig. 4.
The problem then is how to determine the image such
that when it is reflected from the spherical mirror and
lands onto the final display surface, appears correct.