Abstract:
A novel decoy providing the deceptive appearance of a genuine three-dimensional object, such as a vehicle, is described which comprises a plurality of modular table units each of predetermined shape and assembled in an abutting relationship to form an outline of the vehicle, each said table unit supported by a framework including leg elements in a spaced relationship above the ground whereby a shadow is cast in said outline, to further the deceptive appearance of said decoy as viewed from the air, and a vertical element, supported by said assemblage of table units, in the shape of an elevational view of said vehicle, to provide a deceptive elevational view of said vehicle.
Abstract:
A method of measuring haze in a transparency includes the steps of illuminating a transparency to be measured from one side using a semi-collimated light source disposed in a predetermined angular relationship to the transparency, measuring the illumination (E) falling on a surface of the transparency from the one side thereof, then along a predetermined line of measurement through the transparency using a photometer to measure the veiling luminance (L) within the transparency from another side of the transparency opposite to the one side thereof, and, finally, calculating the haze index of the transparency by solving H.sub.i =L/E.
Abstract translation:测量透明度中的雾度的方法包括以下步骤:使用以与透明度成预定角度关系设置的半准直光源从一侧照射待测量的透明度,测量落在该透明体的表面上的照度(E) 然后通过使用光度计的透明度沿着预定的测量线测量透明体中与透明体的与其一侧相反的另一侧的遮盖亮度(L),并且最后计算 透明度的雾度指数通过求解Hi = L / E。
Abstract:
A replaceable anti-reflection shield for the glare surface beneath the windscreen of a vehicle is described which comprises a flexible panel of light absorbing material, such as black cloth, velvet, canvas or plastic, of size and configuration corresponding to that of the glare surface for placement on and conformance to the contour of the glare surface beneath the windscreen, and peripheral attaching means such as adhesive strips, snaps, Velcro.RTM. strips, suction cups, or similar devices, on the flexible panel for detachably securing the peripheral edges of the panel to the glare surface, whereby the panel is easily removed for cleaning or replacement.
Abstract:
A novel vision tester and vision testing method is described which comprises a pair of translucent displays, each transilluminated by electroluminescent lighting panels, the images of the two patterns being superimposed to provide a combined image characterized by a pattern of variable contrast. Light sensors near each light panel provide a measure of the relative intensities of the two images, which provides a measure of the contrast of each combined image. Contrast may be directly read out by processing the signals from the light sensors. The tester may be battery powered for portability.
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.
Abstract:
A laser energy window arrangement especially usable in a tactical aircraft having night vision equipment-aided cockpit visual information input requirements. The laser energy window arrangement enables use of laser apparatus directed external to the aircraft for target designation or other purposes while minimizing the amount of energy from such laser returning spuriously inside the cockpit where it inherently acts a noise signal for night vision equipment. The laser energy window limits the portion of the aircraft windshield or canopy exposed to laser radiation and its effects to a relatively small area, an obscurable area generating significantly reduced amounts of spurious return energy in comparison with use of the laser directly through an unlimited windshield, canopy, or other type of transparency. Transmission of spurious return energy from the laser energy window to remaining portions of the windshield or canopy is precluded by interruption of transmission paths within the windshield or canopy material and transducing the interrupted path energy into heat dissipated within or outside of the aircraft and not affecting the remainder of the canopy. Potentially increased aircraft to target standoff range, reduce need for aircrew use of laser eye protection gear, reduced laser induced windshield or canopy degradation and other benefits are identified for aircraft uses of the invention. Use of the window invention in other non aircraft and non military aircraft settings is also contemplated.
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.