1. A method to correct for rotational distortions of an image projected from a projection source on a viewing surface, said method comprising: acquiring an image of a scene containing the viewing surface, using at least one image capture device with a known orientation relative to the projection source; identifying at least a first pair of parallel lines in the image; identifying at least a second pair of parallel lines, orthogonal to the at least first pair of parallel lines, in the image; obtaining coordinates of vanishing points corresponding to the at least first and the at least second pair of parallel lines; computing angles of rotation of the at least one capture device with respect to a frame of reference, using the coordinates of the vanishing points; and constructing a correction transformation using the rotational angles and the orientation of the at least one capture device relative to the projection source.