Abstract: A system using a ray-tracing algorithm and a hierarchy of volume elements (called voxels) to process only the visible surfaces in a field of view. In this arrangement, a dense, three-dimensional voxel data base is developed from the objects, their shadows and other features recorded, for example, in two-dimensional aerial photography. The rays are grouped into subimages and the subimages are executed as parallel tasks on a multiple instruction stream and multiple data stream computer (MIMD). The use of a three-dimensional voxel data base formed by combining three-dimensional digital terrain elevation data with two-dimensional plan view and oblique view aerial photography permits the development of a realistic and cost-effective data base. Hidden surfaces are not processed. By processing only visible surfaces, displays can now be produced depicting the nap-of-the-earth as seen in low flight of aircraft or as viewed from ground vehicles.

Abstract: A system for washing the air in a coastal environment in which a volume of air moves from a land mass to a water mass. The system includes a plurality of fountains 12 mounted offshore which spray a volume of water into the path of the air flow. Water is stored under pressure and selectively released to form the spray. In specific embodiments, wave motion is used to provide the power to pressurize the stored water. Wave power is extracted by dual reciprocating pumps 50 and 51 connected to a float 40. Wave power is amplified by lenses 20 which focus the waves onto the floats 40. A control system 100 senses pollution and controls the generation of the spray. In addition, wave motion is sensed and used to control the position of the lens 20 for optimum performance and minimum wear.

Abstract: An analog optical processor for performing affine transformations and constructing fractal objects. An optical processor for optically performing an iterated affine transformation includes a rotating prism, an imaging lens and a translatable mirror, together with a pulsed laser as an input light source and an image detector array to record the final transformed image. The amount of rotation is determined by the setting of the rotating prism. The imaging lens provides the required magnification or demagnification. The translating mirror is shifted to provide the necessary translation. The pulsed image passes through the optical loop many times to perform the transformation. An optical Iterated Function System is implemented by connecting a plurality of the optical loops in parallel, together with shutters or beamsplitters for guiding the pulsed image to different loops according to the probabilities assigned by the Iterated Function System.

Abstract: A display system is disclosed which employs multiple holographic elements for selectively reflecting images from separate projectors to one or more distinct viewing volumes. The display system provides the capability to project differing perspective images to individual crew members located at separated positions within a training simulator.

Abstract: An electro-optical system that implements the self-tiling process of fining proper Iterated Function Systems for modeling natural objects. The system can operate in two different modes, a real-time interactive mode and an automated mode. The purpose of the system is to speed up the process of finding a proper IFS for a given object to be modeled. The system makes use of optical processing, including optical means for rotating, magnifying/demagnifying and translating an input image. Optical beamsplitters are used to combine transformed images to produce a tiled output image. In one embodiment, an automated controller evaluates the goodness of the match between the tiled image and the input image and generates control signals which cause adjustment of the settings of the optical means. The process is repeated automatically until the match is sufficiently good. The invention can also be operated in a manual, man-in-the-loop mode.

Abstract: The invention provides a non-linear projection system, which includes a variable acuity non-linear holographic optical element (HOE), and an apparatus for creating the HOE. The projection system comprises a computer, a light valve which projects images generated by the computer, a lens train for focusing the images projected by the light valve, an HOE for the non-linear refraction of the focused images and a hemispherical viewing screen. The system additionally provides means for maintaining the center of the projected images in alignment with center of the field of view of an observer. The variation of the pixel size and spacing created by the system matches the variation of the human visual acuity of the observer permitting a realistic view to be presented while requiring a minimum of computer data to be generated and projected. The apparatus for creating the HOE utilizes a laser beam, three lens trains and a holographic recording medium.

Abstract: A system for detecting the presence of known materials in a body or container. The system incorporates a gamma or X-ray source for irradiating the body with gamma rays to produce X-ray fluorescence of materials contained therein. A directionally discriminate X-ray detector is positioned to intercept X-rays emitted from the body and is adapted to pass only those X-rays having a predetermined wavelength and incident from a specific direction that are characteristic of a material of interest contained in the body. The detector includes a dislocation free single crystal having substantially parallel input and output surfaces. A second crystal aligned parallel to the first crystal may be disposed at a position offset from the first crystal to receive the X-rays transmitted by the first crystal in order to discriminate between materials fluorescing within the body. In a specific embodiment of the invention, the first detector comprises an elongated crystal which pass X-rays in accordance with the Borrmann effect.

Abstract: A method for use with a vehicle simulator which provides for the rapid update of displayed terrain data in areas of non-visible terrain surfaces and terrain image discontinuities. The method is for use with a system which projects a time-varying computer-generated image scene representative of the terrain as viewed from a moving vehicle. The image scene is derived from a digital data base stored in slow speed secondary memory. The method includes the steps of predicting, by means of line-of-sight sampling ray, which segments of the data base could be visible after a predetermined time interval. The data base is accessed for the predicted segments of data and these segments are retrieved therefrom. The data segments designated are then stored in predetermined memory locations in high-speed main memory. Finally, selected ones of the stored segments are displayed based on the actual vehicle path and position after the predetermined time interval has elapsed.

Abstract: A deformable mirror system for reduction of projected image distortion in an optical system is disclosed. The mirror is adapted to correct for ray direction. In accordance with the invention, a mirror is located near an intermediate image plane. The distortion in the image is predetermined, and the mirror is contorted in a manner determined by the distortion to be corrected; relationships are prescribed for the desired contortion. Significant reduction in distortion can be achieved by placement of a mirror near the image plane; furthere reduction can be achieved in accordance with the invention by the placement of an additional contorted mirror at a subsequent image-forming aperture in the optical system.

Abstract: An improved radiation source is disclosed, exploiting the spontaneous radiation generated from the interaction of an electron beam and a conductive grating. Conditions are defined for generating coherent or noncoherent radiation, and for extending the tunability of the radiation source from millimeter, IR, visible and UV wavelengths to x-ray wavelengths, and for generating multiple wavelengths simultaneously. Conditions are disclosed for enhancing the intensity of the spontaneous radiation, anf for modulating the radiation.

Abstract: An orthogonal coil metal detector with nesting rectangular coils, each comprising a plurality of turns encapsulated in an insulating material and having a layer of electrical resistive material thereon. An encapsulating material in the gap between the coils bonding the coils together. A fixture for supporting the coils in spaced relations and providing for translation and rotation of one coil relative to the other for adjusting the coil position to a minimum coupling condition, and for holding the coils in the adjusted condition during curing.