Abstract: A method for dynamically recording distortion in a transparency includes a support fixture for mounting the transparency for movement about a predetermined horizontal or vertical axis, with a camera disposed in back of the transparency while a test target is disposed in front of it. The test target has a plurality of small light sources arranged in a rectangular matrix pattern toward which the camera is aimed through the transparency. By opening the camera shutter for a period of time as the transparency is moved through a predetermined angle, a photographic record of distortion at a plurality of regions in the transparency is produced.

Abstract: An improved aerial refueling system, suitable for operation under nighttime or other limited visibility conditions, is described, and comprises a tanker aircraft with refueling boom depending rearwardly thereof, a receiver aircraft having a fuel receptacle for interconnection with the boom, means disposed on the tanker for illuminating the receiver aircraft with infrared light during hookup and refueling, infrared sensitive viewing means and an optical imaging device on the tanker through which the boom operator may view the boom and receiver aircraft to guide the boom into position for connection with the receiver aircraft.

Abstract: An improved system for measuring absolute angular deviation through transparencies, such as aircraft windscreens, uses an incoherent light source and a target configuration in the form of an opaque slide with a transparent "L"-shaped pattern. The positions of images of the legs of the "L" after passing through the transparency are detected at separate times by a single CCD array through rotation of the image of the "L"-shaped pattern ninety degrees by rotation of a Pechan prism about the optical axis of the system. In such manner, horizontal (azimuth) and vertical (elevation) components of angular deviations is measured for each tested point on the transparency, uncontaminated by lateral displacement errors.

Abstract: An improved system for measuring absolute angular deviation through transparencies, such as aircraft windscreens, uses an incoherent light source and a target configuration in the form of an opaque slide with a transparent "L"-shaped pattern. The positions of images of the legs of the "L" passed through the transparency are detected by CCD arrays for measurement of the azimuth and elevation components of angular deviation for each tested point on the transparency, uncontaminated by lateral displacement errors.

Abstract: An apparatus for altering the spatial frequency content of recorded patterns by selectively filtering the patterns after they are transformed into the Fourier domain. The filter characteristics are spatially and temporally variable while the real space image of the altered pattern is being observed. A laser beam is projected through a transparency containing the pattern. The patterned beam, with diffraction interference effects, is transformed to the Fourier domain at the surface of a liquid crystal light valve responsive to a spatially and temporally varying light projector. The projector activated regions reflect areas of the Fourier domain beam, while other areas are absorbed or incoherently reflected. A beam splitter redirects a portion of the reflected beam to a continuously observable image plane after transformation back into real space.

Abstract: A vibration stabilized image projection system includes a viewing screen supported on a vibratory platform, an image projector supported off the platform in a relatively vibration-free environment for projecting an image toward the screen, and an image stabilizing lens interposed between the projector and screeen for providing an optical link between them. The stabilizing lens is supported on the platform for undergoing vibratory movement therewith in X, Y and/or Z planes and relative to the projector. The lens focuses the image at a stationary position on the screen as the stabilizing lens, screen and platform undergo vibratory movement relative to the projector.

Abstract: An apparatus for analyzing the deleterious characteristics of optically transparent bodies, including distortion, multiple imaging and birefringence. A beam of light is projected along an optical axis onto a beam splitter. The reflected segment passes through the transparent body and is then reflected back along nearly the same path toward the beam splitter by a retro-reflective screen lying at the image plane of the beam. The portion of the reflected beam passing directly through the beam splitter is detected by an optical sensor in substantial orientation with the axis of the beam reaching it. Distortions and multiple imaging are detected by shape changes and images, respectively, in a pattern of opaque areas superimposed on the originating beam. Birefringence is analyzed by polarizing the originating beam and observing the color pattern and intensity reaching the sensor.

Abstract: An apparatus for creating images of nonperiodic patterns, which patterns are variable in contrast with respect to a uniform and constant level of background luminance. Two beams of uniform luminance are projected through individual, orthogonally oriented linear polarizers, and then into a common cube beam splitter to be divided and interlaced. One combined output beam from the splitter is projected through a rotatable linear polarizer onto the image sensing optical detector undergoing test. The second beam is projected toward a detection system. The patterned region of the second beam passes through a second rotatable linear polarizer, synchronized to the first rotatable polarizer, and onto a CCD array detector system. Contrast between the pattern and the background is represented by the two electrical voltage levels in the array output, irrespective of the spatial frequencies in the pattern.

Abstract: A measurement apparatus and method for detecting, resolving and quantifying the distortion caused by a relatively large region of a distorting optically transparent medium. A precisely defined pattern is viewed through the transparent medium to introduce the distortion effects. The altered pattern is photographically recorded in thin film transparency format. A beam of coherent luminous energy projected through the transparency, once focused, produces a Fraunhofer diffraction pattern which is the Fourier transform of the original pattern. Conventional distortion characteristics in the Fourier domain appear in a form more amenable to quantification and analysis. The character and magnitude of the distortion is readily ascertained by comparing the transforms of distorted and undistorted patterns, yielding quantitative data comparable to conventional distortion effects in terms of grid line slop and lens factor.

Abstract: An apparatus for detecting contact between an object and the surface of a body, by utilizing various indices of refraction so that electromagnetic energy reaches a detector system only when there is optical contact. A body of transmissive material is irradiated with electromagnetic energy. That portion of the energy which enters the body through a first boundary surface is refracted, thereby striking the body surface leading to the detection system at angles of incidence sufficient to cause total reflection at that surface. Similarly, electromagnetic energy which passes through the body, strikes the object on the opposite side, and reenters the body is refracted upon reentry and totally reflected at the surface leading to the detector system. Contact between the object and the contact detecting surface produces diffusive reflection within the body at all points of actual contact.

Abstract: An optical device for measuring the angles formed between a line-of-sight and the normal to a planar surface intersected thereby. A solid piece of optically transparent material having a relatively large index of refraction is geometrically shaped to have a planar base surface, with a reference mark theron, and a curvilinear viewing surface with scale marks to designate angular orientations. The exterior surfaces are optically polished to create mirrored surfaces for internal reflection. To accentuate contrast, the planar surface containing the reference mark is coated with a layer of contrasting opaque material. Angles are measured by placing the planar base surface of the device on the planar surface intersected by the line-of-sight and aligning the reference mark with the point of intersection. When viewed from the observation point defining the line-of-sight, an image of the reference mark appears on the scaled surface at a location representing the line-of-sight angle.

Abstract: An apparatus for generating patterned images which are variable in color contrast and spatial frequency while retaining a substantially constant, uniform level of photometric luminance. Two broad spectrum beams of luminous energy are individually projected through two orthogonally oriented polarizers and interleaved upon being split. The intensity in one beam is homogeneous while the other contains a spatially periodic pattern. The two beams created by splitting and interleaving are selectively color filtered and combined after one is translated sufficiently to reverse its phase relative to the other. A rotating polarizer in the path of the output combined beam alters the pattern color composition between one extreme where the spatially reversing colors are defined by the color filters and the opposite extreme in which the pattern disappears into a uniform composition of the two colors.

Abstract: An apparatus for detecting the angular deviation from an axis imparted to a ray when passing through a transparent medium, for resolving the angular deviation into its components, and for generating electrical signals accurately representing the magnitudes of such components. A laser beam is projected along an optical axis through the medium and focussed by a displacement compensation lens. The beam is divided into channels with a beam splitter, each channel being incident upon a transmission diffraction grating. Each grating, characterized by fine parallel lines of substantially random size and spacing, generates a fan-shaped region of luminous energy. At a distance equal to the focal length of the lens, the fan-shaped regions cross detector arrays aligned parallel to the grating lines. A change in the angular deviation proportionally translates the crossing point along the detector array.