Abstract: A method of measuring haze of an aircraft transparency includes producing a first reading representative of the level of light scattered by an area of a transparency under test while on the aircraft when it is illuminated by a known light source, and producing a second reading representative of the level of light scattered by a predetermined, preferably worst haze condition, reference plate when it is illuminated by the light source in place of the transparency. Then, a ratio of the first and second readings is calculated to provide a quantitative measure proportional to the degree of haze in the transparency test area.

Abstract: A novel optical device and method for measuring intraocular light scatter in a human vision system of a subject is described which comprises first and second light sources of respective predetermined intensities, the images of which are optically folded along a common optical axis and projected into the vision system of the subject, the first source being of intensity sufficient to generate intraocular haze in the vision system of the subject, the second source being movable in a plane substantially perpendicular to the axis along which its image is projected whereby the second source image as viewed by the subject may be selectively viewed with respect to the first source image to measure the apparent peripheral extent of the haze surrounding the first source image.

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: 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: A novel device and method for determining the contrast sensitivity of a subject is provided and comprises a test chart including a plurality of patches systematically organized in a predetermined array, each patch having a plurality of adjacent patterned areas, at least one of which is a pattern of alternate light and dark regions of predetermined contrast, and the remaining patterned areas are solid gray patterns of predetermined reflectance, each contrast pattern being characterized by a space average reflectance equal to the predetermined reflectance value of the adjacent gray patterned areas. The spatial frequency and contrast of the alternate dark and light regions may be varied in the array of patches. In the method for determining the visual contrast sensitivity of the vision system of a subject, a chart of the invention is displayed to the subject at successively shorter distances, and the greatest distance at which the subject can resolve each contrast pattern is determined and recorded.

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: 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: For determining the extent of surface deterioration of a transparency, a method and apparatus is provided for measuring light scatter or halation produced by the deterioration. An intense light source is placed on one side of the transparency to be tested, and a camera and annular neutral density filter are positioned on the opposite side. The filter is aligned between the light source and camera lens so as to occlude or shade the lens from the direct light rays, whereby light scattered by portions of the transparency outside the periphery of the filter may be recorded on photographic film in the camera. The annular filter contains contrasting rings of varying shades of grey which facilitate standardization of halation measurements made on different transparencies or on the same transparency at different periods in its life cycle.

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 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: A portable visual function tester and testing method is described for rapid and accurate measurement of several human vision parameters, including critical fusion frequency, stereopsis, Snellen visual acuity and visual resolution, cyclophoria, eye dominance, and lateral and vertical phoria, which comprises, first and second illuminated visual displays disposed for viewing by respective left and right eyes of a subject along respective parallel first and second optical axes, each display comprising an array of visual display patterns, one pattern of each display comprising a pair disposed for simultaneous viewing by the subject in the measurement of a corresponding vision parameter; the display patterns include an illuminated blinking disk for measurement of critical fusion frequency, a rectangular array of four-dot sets for measurement of stereopsis, an array of Snellen E designs of various sizes and orientations for measurement of visual acuity, and a resolution fan comprising a pattern of a plurality of rad

Abstract: A method of measuring optical properties of a transparency uses a video camera for focusing and then refocusing an image of a point source of light transmitted through a test region when the transparency is first absent and then later present at the test region. The distance the camera needs to be moved together with the focal length of a focusing lens used in carrying out the method provide sufficient quantitative data to calculate the spherical optical power of the transparency. Also, the camera generates video images of the point source both before and after the transparency is present in the test region. These images are displayed on a screen containing a grid pattern which facilitates measurement of the displacement of the image from the center of the grid or from the optical axis due to the presence of prismatic deviation in the transparency. Given the earlier data and supplemented by the latter displacement quantity, the prismatic deviation of the transpareny can also be calculated.