Abstract:
System and method for in situ measurement of haze in a transparency, such as an aircraft windscreen, canopies, windows or the like are described which comprise an annular light source for illuminating a selected test area of the transparency along a selected optical axis, a photodetector, and a lens for projecting an image of the illuminated test area along the axis onto the photodetector.
Abstract:
System and method for measuring angular deviation in a transparency are described which comprise the steps of directing a large diameter collimated beam of light along an optical axis through a transparency, focusing a portion of the collimated beam, determining the position of the focus of the beam portion relative to the axis, repeating the above steps without the transparency, measuring any difference in position of the focus with and without the transparency, and calculating the vertical and horizontal components of angular deviation in the transparency according to relationships disclosed.
Abstract:
An optical instrument and method for measuring susceptibility to glare of a human vision system is described which comprises a glare light source of preselected intensity sufficient to generate glare in the vision system of a subject, an acuity target having first opaque or partially transparent areas and second translucent areas defining a pattern of recognizable indicia on the target, a housing supporting target and source side-by-side for simultaneous viewing by the subject, and a reflective surface within the housing for directing light from the source onto the back surface of the target for substantially uniform transillumination of the target with light from the source. Optional optical filters may be placed between the source and subject, target and subject, or source and reflective surface, for selectively filtering light viewed by the subject. A movable cover plate may be included for selectively exposing the source to the subject in certain glare susceptibility measurements.
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 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. Two unpatterned background regions from either of the interlaced beams are projected through individual and orthogonal linears polarizers to individual luminance detectors. Each detector, in turn, regulates its corresponding beam intensity to compensate for drift in the beam generating elements.
Abstract:
A method for measuring optical distortion in a transparency is described which comprises the steps of acquiring an analog image of a grid board through the transparency, digitizing the analog image to form a digitized image comprising a multiplicity of pixels defining the shape of the grid board as viewed through the transparency, locating on the digitized image the pixels defining the grid and determining optical distortion of the transparency by comparing the shape of the grid in the digitized image to the actual grid shape on the grid board.
Abstract:
A system for measuring optical angular deviation in a transparency such as an aircraft or automobile windscreen, visor, optical lens or the like is described wherein orthogonal first and second incoherent light line images are combined and separately optically encoded, such as by wavelength or by polarization vector using suitable color or polarization filters or beamsplitters, and projected through a transparency under examination, the combined images then separated to detect simultaneously and separately the vertical and horizontal components of angular deviation at a specific location in the transparency.
Abstract:
A novel instrument and method for measuring the accommodative amplitude and speed of the eye of a subject is described. The instrument for making the measurements according to the present invention comprises a pair of illuminated or luminous visual displays disposed for viewing along an optical axis, the images of the displays superimposed upon each other for viewing by a subject, one of the displays comprising a pattern having a plurality of distinct and recognizable orientations with respect to the axis along which it is viewed, an orientation generator for randomly and alternately generating one of the orientations for viewing by the subject, a switch operable by the subject for turning the displays off and indicating the observed orientation of the random pattern, and a recorder for recording the last displayed orientation and the time the displays were on or the time between presentation of one display and the correct identification of the other.
Abstract:
An image layout arrangement suitable for transposing small template located images into large work surface located images with any required degree of image resolution and detail, using simple, low-cost tools. An exemplary layout of aircraft images to a runway surface for use in enhancing air base survivability is included and employs point-by-point image transposition according to a plurality of point locating arrangements.
Abstract:
A diffuse incandescent runway marker light apparatus has a housing with a visible light diffusing plate mounted in one end and an infrared light diffusing plate mounted in the other end, and a pair of incandescent light sources mounted in the housing and aimed toward the respective housing end plates. A switch, when flipped to a first position, turns on one light source for producing visible illumination and turns off the other light source. The switch, when flipped to a second position, turns off the one light source and turns on the other light source for producing infrared illumination. In such manner, the appropriate type of illumination for marking the runway for overt or covert landing operation may be selected. When the switch is flipped to a third position, both light sources are turned off.