Abstract: An image display apparatus includes a light valve for controlling at least the intensity of light projected along an optical path from a light source through the light valve. The light valve has a plurality of light transmitting elements at least the translucency of each of which may be adjusted periodically such that the translucency of each element is substantially constant except during intervals within which the translucency is being adjusted. A shutter is provided to obstruct the light path through at least one of the light transmitting elements during intervals within which the translucency of the element is being adjusted.

Abstract: A simulator system in which a visual display assembly is arranged to present an image to be viewed on a display surface and a viewing station is positioned in front of the display surface such that a person looking from a predetermined eyepoint defined within the viewing station can see the display surface through a viewing window defined by the viewing station. The viewing station is displaceable relative to the visual display assembly between first and second positions to adjust the position of the display surface relative to the viewing window when viewed from the eyepoint. During displacement of the viewing station between the two positions, the viewing station is rotated about the eyepoint. The actuator is arranged such that the rate of rotation of the viewing station increases with distance from the first and second positions to a maximum when the viewing station is in an intermediate position.

Abstract: The motion of particles such as snow is simulated in a computer generated image which represents the appearance from a predetermined viewing point of a three-dimensional worldspace through which the particles move. A three-dimensional model is defined which is made up from a regular array of abutting cubes of predetermined dimension. An object is defined which dimensions correspond to the dimensions of each cube, the object having characteristics such that it represents the motion of particles through the volume which it occupies. The three-dimensional model made up of the array of cubes is notionally positioned in worldspace such that the viewing point is located within a region of the model selected such that the field of view of particles from the viewing point is always within the model. As the viewing point travels through worldspace, it is translated in steps with the magnitude of each step corresponding to the length of any one side of the cubes.

Abstract: A multi-processor computer system comprises one or more CPUs (1) connected to a host computer (2) via a common PCI bus system backplane (3). The host computer (2) comprises a host microprocessor and associated memory unit and each CPU comprises a local microprocessor (5) having a local bus (15), an associated local memory unit (6), and a PCI connector (9) connected to the PCI backplane. Each CPU (1) further comprises a bridge (7) having at least two decoders installed between the CPU local bus (15) and the PCI connector (9) and providing an interface between the local microprocessor (5) and the associated local memory unit (6). A first decoder (A) of each bridge (7) is programmed to a first address range for access to the respective local memory unit (6) by the associated local processor (5), and a second decoder (B) of each bridge (7) is programmed to a second address range for access to the same physical memory of the memory unit (6) by another microprocessor (5) of the system.

Abstract: A reflector includes a frame over which is stretched a flexible sheet of reflective material to define a curved reflecting surface of pre-determined geometry. The frame defines arcuate sections portions of which support the sheet and lie on the surface of pre-determined geometry. At least one of the arcuate sections is deformable to displace the respective sheet supporting portion and thereby adjust the tension in the flexible sheet.

Abstract: A vehicle simulator is disclosed in which a first motion platform is driven in translation and rotation from a datum position. A simulator user station is positioned on the first motion platform, the user station defining a predetermined eyepoint position and a predetermined field of view from the eyepoint position relative to the user station. A display surface is mounted on a second motion platform so as to lie within the field of view, and the second motion platform is driven to maintain a predetermined positional relationship between the eyepoint position and the display surface. An image is projected to be viewed from the eyepoint position via the display surface.