Distortion correction for oblique projection onto a curved screen

This theoretical discussion deals with obliquely projected images on the surface of curved viewing screens. Resulting perspective and geometrical distortions are usually precorrected with computer software in nearly real time, or by optical printing methods in the case of film. Owing to the significant technical and cost overhead of these methods, there is an interest in producing real-time passive correction using optics supplemental to the normal projection lens. Several concepts to this end are described.