Large dome simulators for air-to-air and air-to-ground aircraft weapons tactics trainers are coming into prominence. In such devices, the training objective is to improve pilot proficiency and coordination by allowing the pilot to train in the use of weapons in realistic operational and threat environments. Typically, the pilot will fight against a TV projected image that is slewed across the field of view. From geometrical considerations, a standard rectangular or square TV image looks distorted to the pilot. The degree and shape of the distortion changes with the shift in location of the "target" on the screen relative to the pilot as it is slewed either by servo pointing the entire projector or by optical means. This paper describes the design and development of a TV projector that is capable of predistorting the TV raster such that from the pilot's viewpoint the image will look rectilinear at all times. This dynamic raster shaping can be updated at the TV field rate (typically 60 times per second) so that there is no perceptible jumpiness in the image as the shape is varied. In addition, the raster can be zoomed to create the appearance of distance change to the target and rotated to compensate the effects caused by the mirror steering of the target image across the dome.
Richard E. Holmes,
"Target TV Projector With Dynamic Raster Shaping For Use In Dome Simulators", Proc. SPIE 0303, Visual Simulation and Image Realism II, (29 June 1982); doi: 10.1117/12.932654; https://doi.org/10.1117/12.932654