Abstract: Known polarization image detection systems produce an image illustrating structural information of a viewed scene which is representative of the degree of linear polarization. The present invention describes an improved detector system which enables more information to be extracted from the scene. The system comprises an optical arrangement having an optical axis (4) about which a retarder (1) and a linear polarizer (2) can be independently rotated, for producing a focussed image on a detector. This arrangement can be expressed mathematically in terms of Stokes parameters and Mueller matrices, and the expression can then be solved to provide three different polarization images representative of the viewed scene.

Abstract: This invention relates to improvements in so-called "virtual reality" computer systems. The display system described enables the effective integration of computer generated images and real, naturally occurring images in the visual display units which provide the user with his entire visual stimulation. Areas of the user's notional field of view where computer-generated imagery is required (for example the cockpit canopy in an aircraft flight simulator) are coloured with a predetermined colour or intensity. Two video cameras are provided, each of which is mounted so that its field of view corresponds to a respective one of the notional fields of view of the user's eyes. The signals from the video cameras are analysed to determine the presence of the predetermined colour or intensity, thereby giving an indication that a computer generated image is required for that part of the video camera's field of view.

Abstract: A control system suitable for incorporating in control panels and effecting remote control of apparatus includes a light guide bus system including input and output light guides and optical switches carried on a removable optical bridge member bridging in use the input and output light guides so that the switches may be selectively connected into the bus system. Each switch is of a known optically encoding type which on operation of that switch passes its particular control code into the light guide bus system for subsequent decoding and appropriate control of the apparatus.

Abstract: A disclosed canopy testing using an area imaging device, e.g. a T.V. camera, to view a scene, a cross-hatch pattern say, through the canopy. The viewed image is digitized and stored and a computer evaluates the target image by comparing the apparent positions of its features with their real positions and/or by sensing deviations from straightness of the pattern lines. In a development, a polarimeter or polarization sensitive camera is used to test for hazing and curvature defects.