GB945395A - Improvements in optical illusion devices - Google Patents

Abstract

945,395. Flight training apparatus. GENERAL PRECISION SYSTEMS Ltd. March 28, 1962 [March 28, 1961], No. 11375/61. Heading B7W. In flight training apparatus of the kind providing for relative motion between a model terrain and the entrance pupil of an optical viewing device so that a trainee has an illusion of motion of the terrain as seen from the viewpoint defined by the entrance pupil, means are provided for simulating the effect of atmospheric mist or haze comprising a screen member having a substantially straight edge and so positioned that its face may form the sky in the scene image and its edge the apparent horizon, the member being so adjustable that its edge can appear controllably diffuse in simulation of the effect of haze or mist. A perspective image of a flat model terrain M is produced on the photomosaic A of a television camera by lens L 1 having an internal stop S of small dimensions. The entrance pupil formed by the stop is transferred forward by a pair of lenses L 2 and L 3 to a position S 1 , which becomes the effective viewpoint of the system. An opaque white screen B is positioned with its lower edge substantially coincident with the true horizon level and is mounted for travel bodily along a line approximating to the horizon viewing direction so that as it approaches the position S 2 the image of its lower edge becomes more and more blurred thus producing a more progressive obscuration of the scene over a larger vertical viewing angle. Means c may be provided for illuminating the face of the screen.