Abstract:
A luminous flux measuring apparatus includes an integrating hemisphere which has a hemisphere shape and an inner wall. The inner wall has a light diffusing material applied thereto. A flat mirror is installed to cover the first opening of integrating hemisphere. A second opening is located at the center of the flat mirror and the window has the same configuration of longitudinal cross section of the illuminant to be measured. A light detector which has a light-intercepting window is located inside the integrating hemisphere. Finally, the flux measuring apparatus includes a means for holding the illuminant in the window of the mirror at the center of curvature of the integrating hemisphere.
Abstract:
A two-stage light collector, including a first stage which admits a scanning beam and a second stage which is optically connected to the first stage and has a light detector therein. The first stage has a shape which re-images diffusely scattered radiation from a target on which the radiation impinges. The first stage directs light toward an entrance aperture in the second stage which indirectly reflects light toward the detector associated with the second stage.
Abstract:
Method of and apparatus for measuring thermal radiation geometric configuration factors - any such factor being that fraction of the total radiant energy emitted from an energyradiating surface which is incident on an energy-receiving surface. The method includes the steps of forming an image of the projected area of an energy-radiating surface at a selected location along an energy-receiving surface, making a photographic reproduction of such image, repeating the image-forming and image-reproduction steps at a plurality of selected locations along such energy-receiving surface, providing a configuration factor grid for subdividing any such image into weighted areas equivalent to known thermal radiation geometric configuration factors, and inspecting each photographic reproduction with such grid to measure the area of the image thereon in terms of its radiation configuration factor, thereby enabling all such factors to be averaged to derive a value for the entire energy-receiving surface. The apparatus includes an image-forming assembly comprising primary and secondary mirrors of hemispherical configuration for collecting and forming an image of the energyradiating surface as the area thereof is projected onto the primary mirror, and further comprising an intermediate optical system for receiving such formed image as redirected thereto by the secondary mirror and for transmitting to and focusing such image at an image plane for photographic reproduction.
Abstract:
An optical instrument including means for selecting one of several magnifications of an image being viewed, the selective magnification means being positioned in a collimated light path between an objective lens and a viewing lens and without change of conjugate distances therebetween; also an aperture stop located at one conjugate plane of a relay lens, the other conjugate plane being the nodal plane of the objective lens, which serves as a light-attenuating means without interference with the viewing optical system or without affecting the field being measured.
Abstract:
Advanced sensor evaluation and test apparatus comprises a vacuum chamber with an inner cryoshroud, housing an on-axis optical parabolic collimator, a radiant energy source assembly having an output aperture located in the focal plane of the collimator, a calibration monitor consisting of a Cassegrainian type radiometer that occupies one portion of the collimated radiant energy beam and which forms an image of the source on a bolometer, and a pair of scanning mirrors directing energy from another portion of the collimated beam into the entrance aperture of the optical sensor under test. In addition, a background radiant energy generator can direct radiant energy simulating elevated radiation background to the sensor under test which, in turn, forms an enlarged image of the background source in its own detector plane. One version of the source assembly includes at least one blackbody radiation source of variable aperture and temperature with a chopper operating to provide modulated radiation which is projected into an integrating sphere coupled with a source projector. An adjustable dual reflector with one specularly and one diffusely reflecting surface is mounted inside the integrating sphere and can be rotated to predetermined orientations to function in either a specularly reflecting mode or diffusely reflecting mode. In a third mode of operation, the mirror is rotated into an inactive orientation in which it does not intercept the beam entering the integrating sphere. This is the integrating sphere mode of operation. Another version of the source assembly includes at least one blackbody radiation source providing radiation to an integrating sphere coupled with a radiation guide (pipe). The radiation guide can be either a single or dual guide (pipe) and is cooperatively structured to operate with selected transmission patterns (transparent portions) on a movable disc sector positioned at the end of the guide.