Abstract: Using the Extense Source Formulation (Irazoqui et al., 1973a), a radiation distribution model for the tubular lamp-elliptical reflector system was developed for predicting energy density profiles inside the elliptical cavity of the system. It introduces a significant improvement over the linear-lamp models since it avoids any form of singularities in the prediction of radiation energy density profiles at the focal points of the elliptical reflector. Also, all lamp and reflector dimensions are parameters of the model. Calculated results agree well with published experimental data for a similar lamp reflector set up. One of the most important conclusions is the absence of uniform irradiation from all radial directions at the reactor location.

Abstract: A reproduction camera has a carrier for a replaceable objective lens and a carrier for the image plane, both carriers being movable to different distances from a copy holder by electric motors, and an electronic digital computer, which determines the actual distances of the carriers from the holder by counting electrical pulses generated upon incremental movements of the carriers (as by pole passages of the motors, or directly); the desired distances for sharp focus, corrected for T (distance of the objective lens from the objective carrier) and HH'' (distance between principal focal points) are computed on the basis of the desired magnification and the focal length of the selected lens, and are compared with the actual distances; and the motors are controlled as the results of the comparisons of the actual and the desired distances.

Abstract: This invention integrates a spectrometer capability with the basic imagery function of facsimile cameras without significantly increasing mechanical or optical complexity, or interfering with the imaging function. The invention consists of a group of photodetectors arranged in a linear array in the focal plane of the fascimile camera with a separate narrow band interference filter centered over each photodetector. The interference filter photodetector array is on a line in the focal plane of the facsimile camera along the direction of image motion due to the rotation of the facsimile camera''s vertical mirror. As the image of the picture element of interest travels down the interference filter photodetector array, the photodetector outputs are synchronously selected and sampled to provide spectral information on the single picture element. The selection of the proper photodetector and data sampling is controlled by information derived from the servo system controlling the vertical mirror rotation.

Abstract: An anamorphotic optical system comprising a spherical lens unit and two cylindrical lens units, one in front of the spherical lens unit and one behind it, the two cylindrical lens units being individually parfocal between their cylindrically active and cylindrically passive planes with respect to the object plane and the focal plane of the spherical lens unit.

Abstract: A system for determining the direction from which an illuminating laser beam is received. A cylindrical optical system focuses a laser beam from the field of view as a sharp line image at its focal plane. An encoder plate having a plurality of encoder tracks of differing resolution is located at the focal plane with the tracks positioned perpendicular to the line image. An array of radiation detectors nonfocused radiation passed by the plurality of tracks. The output of the array is a digital word representing the position of the line image on the encoder plate which in turn defines the position of the laser source in the field of view.

Abstract: Infrared radiation can be gathered from a number of discrete, spaced-apart fields of view and focused on a single sensing element with a multifaceted mirror. Each facet of the mirror is a concave surface, preferably spherical, which is focused on the radiation sensing element. This focusing can conveniently be accomplished by the use of a spherical surface having a radius of curvature half that of the individual segments which constitute the facets of the multifaceted mirror. The individual segments'' focal points, which are midway between the spherical segments and the centers of curvature of the spherical segments, are thus all located in a common point, at which the radiation sensing element is located.

Abstract: This invention relates to a method and apparatus for acceptance testing of photographic objective lenses. It includes evaluating the lenses' optical performance at several representative locations in the focal plane. The apparatus incorporates certain features that simplify the signal processing necessary to determine whether a specific objective lens is acceptable or not.

Abstract: A quadrant detection system having an objective lens and a holographic lens positioned at the back focal plane of the objective lens. Four photoelectric detectors are positioned on the side of the holographic lens remote from the objective lens. The holographic lens has lens elements in four quadrants with each quadrant having a focal point corresponding to the position of the photoelectric detectors.

Abstract: A cathode-ray tube arrangement for presenting third dimensional effects without the use of special glasses and without mechanical motion. The device combines the features of integral photography with a unique set of electron optics duplicating the action of the ''''fly''s eye'''' lens array looking at a moving point of light. A mosaic of tiny pictures is generated at the phosphor plane, and these are carried forward to the focal plane of the lens array through a fiber-optic face plate. These multiple pictures represent the light rays from a point of light as some position in the image space. The electron beam within the tube acts in a manner equivalent to the source of light for the picture mosaic. Ordinary deflection and focusing circuits are used to provide for shifting the image of the point of light very rapidly, and beam intensity modulating means are used to produce a complex flickerfree three-dimensional presentation in the image space.

Abstract: Specific arrangements of optical elements are utilized in various demagnifier embodiments to provide scan angle demagnification of a scanning beam in a light scan system which utilizes a rotating mirror polygon, and further beam redirecting optics, to produce the scan. Scan angle demagnification may be achieved by locating the rotating mirror polygon within the beam redirecting optical means relative to a spot forming lens to provide a ratio of conjugates, and thus a final scan angle of proportionately smaller angle than the initial scan angle. That is, the initial scan beam reflected from the rotating mirror polygon to the elements of the beam redirecting optics form an angle theta with respect to the optical axis of the system. Upon traverse of the beam redirecting optical elements, the resulting scan beam crosses the optical axis again at a point beyond the beam redirecting optics at a smaller angle phi , thus providing a final scan beam with scan angle demagnification. The invention may employ negative and positive reflector and/or refractor lens elements in association with, or as part of, the beam redirecting optics, to provide the scan angle demagnification effect. In the invention combination, selected refractor lens elements inherently provide a nonlinear distortion, which is utilized to advantage to make the spot position on the focal plane substantially a linear function of the tangent of the field angle. The distortion correction may further be utilized to advantage to produce a flat focal field, and thus a flat scan line at the recording medium.

Abstract: A system for forming an image of an object in an image plane is described By disposing a reflecting diaphragm in the back focal plane of an objective lens system, the curvature of this diaphragm being adjustable by means of a control element to which an electric signal supplied by an image detection system is applied, the size of the image in the image plane can be rendered independent of a change in the distances from the object to the optical system and from this system to the image plane

Abstract: An optical measuring device employs an objective lens and an adjustable diaphragm disposed in a focal plane of the lens. The diaphragm has a portion formed as a reflecting surface so that part of the light from the object focused by the lens on the diaphragm passes through the aperture, while the remaining light is reflected by the reflecting surface. Measuring means is disposed behind the diaphragm to receive and measure the light passing through the aperture, and a viewing optical system receives the light reflected by the reflecting surface of the diaphragm.

Abstract: Previous calculations of electron trajectories and first-order focal properties of the two-tube electrostatic lens have been extended to a voltage ratio of 1000. Considerable ultrafocal refraction occurs in these strong lenses, with the result that near the highest voltage ratio studied the two focal points are both on the low-voltage side of the lens and nearly coincident. The results are presented in the form of a table and P-Q (image-object) curves.

Abstract: An active optical fuze is provided for detecting the transit of a target through a given focal plane and energizing a firing circuit in response to such event. A pair of optical transmitters are alternately pulsed at a known pulse frequency to illuminate two related foci on an approaching target. When the target is not at the focal plane a pair of optical receivers receive light reflected from both foci in-phase. When, however, the target is at the focal plane, the two receivers are illuminated out of phase by only corresponding ones of said foci. In this latter mode of illumination the receivers drive, respectively, the SET and RESET terminals of a bistable multivibrator to thereby generate a firing signal of the same known pulse frequency as that driving the transmitter, which firing signal is then applied to a detecting and firing circuit to energize the latter as the target transits the focal plane.

Abstract: This paper is concerned with the interaction of an electromagnetic cylindrical coherent wave with a single cylindrical lens. The fields outside and inside the lens are derived from the rigorous solution of a boundary-value problem. The lens used here is double convex and has dimensions of the order of the wavelength. Three types of incident waves are used, a plane wave, a cylindrical wave produced by a line source, and a limited-wave-front wave. There is no energy concentration at the geometrical focus; nevertheless, the lens remains convergent and concentrates energy near the optical axis. The computed results are compared to those obtained by means of well-known optical methods. Good agreement exists between the two methods, at least on and near the optical axis. The plane wave is a good approximation for a limited-wave-front wave over a large part of the lens axis and for off-axis points in the angular sector (−30°, +30°).

Abstract: : It is proposed to use the method of finite elements to calculate the strength of ship structures. The structure is broken down into a definite number of structural finite elements that interact with each other at a limited number of contact (nodal) points. Writing out the equilibrium conditions for these points, the authors obtain the necessary linear algebraic equations to determine the main unknowns (displacement components of the nodal points). Using the unknowns that have been found, the stress state is then determined in each of the elements and, consequently, in the structure as a whole.

Abstract: It is proposed to use the method of finite elements to calculate the strength of ship structures. The structure is broken down into a definite number of structural finite elements that interact with each other at a limited number of contact (nodal) points. Writing out the equilibrium conditions for these points, the authors obtain the necessary linear algebraic equations to determine the main unknowns (displacement components of the nodal points). Using the unknowns that have been found, the stress state is then determined in each of the elements and, consequently, in the structure as a whole.

Abstract: The feasibility of designing and fabricating a small optical system to compensate for motions of a stellar field image on the focal plane of a large orbiting telescope is examined for a single-axis system. An all-reflecting two-mirror star image motion compensator maintains both a flat focal plane and image focus for one or more star images. Both theoretical and experimental evaluations show that only one adjustment is needed to aline the system since the change in focus is linearly related to the misalinements of all critical components. Results of an error analysis show that the focus error resulting from fabrication tolerances is very small compared to the adjustment capability of the system.

Abstract: A radiometric non-scanning extended-source position-indicating device is provided for determining the position of the edge of an extended source which is independent of the irradiance of the source and relatively independent of any radiation variation of the source. The radiometric device includes an objective lens having a rectangular aperture with radiation detector means optically positioned at the focal plane of the objective lens. The radiation detector means has a rectangular field stop in the focal plane of the objective which determines the rectangular field of view. A reflective vane extending from the detector means along the optical axis toward the objective lens splits the radiation applied from the rectangular objective aperture onto the detector means, producing signal from the detector means which is linearly proportional to the object position in the field of view. The same result is obtained by utilizing a rotating chopper which extends to the optical axis at the proper point for splitting the radiation falling on the detector means.

Abstract: An optical data processing system using paraboloidal reflecting surfaces is disclosed. In the preferred embodiment the paraboloidal reflecting surfaces are segments of a paraboloidal mirror. A source of coherent light is in the focal plane of the first paraboloidal mirror segment which collimates the beam and reflects it toward a second paraboloidal mirror surface. The information to be analyzed, on a transparency for example, is placed in the collimated beam. The beam is reflected from the second paraboloidal mirror segment and focused on a Fourier transform plane. A photon detector could be placed in the Fourier transform plane or suitable spatial filters can be placed thereat, with the filtered beam then being reflected from a third paraboloidal mirror segment to be focused on a reconstruction plane.

Abstract: 1332954 Photo-electric direction finders THOMSON-CSF 1 Dec 1971 [4 Dec 1970] 55829/71 Heading H4D A light source tracking device comprises an input device focusing the tracking field on to a rectangular area in its focal plane, means for detecting the radiation received on said area, divided into rectangular juxtaposed strips parallel to one axis of the area, an optical scanning means interrupting the radiation by a succession of transparent lines on a dark background forming a pseudo-random code (PRC) parallel to the second axis of the area and moving parallel to the first and processing means including autocorrelation of the detected signal with a reference signal synchronized with the PRC to provide indication of the angular coordinates of the source. In an aircraft or missile tracking system utilizing optical, infra-red or ultra-violet radiation lens 1 focuses the source on to an array of photodetectors D 1 -D N . Support 3 which may be a disc (Fig. 2, not shown) has strips R 1 -R P representing a PRC photographically produced thereon and moves with velocity V in the direction of the X axis. The detector outputs pass to shaping amplifiers C 1 -C N and thence to photo-emitters E 1 -E N . These emitters are focused on to the support 3 to form a replica 4 of the detection area and the patterns on the support are identical at each instant at the detection and correlation areas. The correlation area 4 is imaged on to the screen 7 of a TV camera. The screen 7 receives the correlation of the detector output modulated by the PRC with the pattern of the correlation area 4. This provides a correlation peak at the position of the source image and the cartesian co-ordinates thereof are determined by scanning the screen 7 line-by-line. The cartesian coordinates are then processed to give the angular mis-alignment of the tracking device. In a modification there are provided N tracks on the support 3 each having a unique PRC. In this case the detection area is focused by a cylindrical or spherical lens on to a single rectangular or point detector and only one emitter is necessary.

Abstract: This paper presents a method of full-field displacement measurement which is very advantageous in auto-safety studies. A linear ruling of parallel lines is projected on the object with an ordinary projector. A view camera completes the apparatus and is used to image the object in its local focal plane. If the object is of arbitrary shape, the image of the ruling becomes "warped" when the camera axis is offset from the projector axis. This "warped" ruling contains information about the object contour which can easily be extracted. Superposition of a linear ruling with the warped ruling yields absolute contour information directly. Superposition of two warped rulings yield contour difference information. The latter process may be conventionally used for studies of deformations due to impact. Examples dealing with knee impact upon instrument panels will be shown. The sensitivity of the method may be varied over a wide range and the need for extreme degrees of vibration isolation is eliminated.© (1973) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Abstract: A compilation of analytical and experimental data is presented concerning the stellar figure sensor. The sensor is an interferometric device which is located in the focal plane of an orbiting large space telescope (LST). The device was designed to perform interferometry on the optical wavefront of a single star after it has propagated through the LST. An analytical model of the device was developed and its accuracy was verified by an operating laboratory breadboard. A series of linear independent control equations were derived which define the operations required for utilizing a focal plane figure sensor in the control loop for the secondary mirror position and for active control of the primary mirror.

Abstract: The image properties of a parabolic radio telescope have been investigated The uncertainty relation has been used for an evaluation of the minimum resolvable intensity within the focal plane and for the calculation of the useful image field The studies have provided that a reception with the whole aperture permits an image field of $$\sqrt \pi $$ beam-widths without any error for a Gaussian illumination

Abstract: The structure of the electromagnetic field near the focus of a stigmatic lens is investigated by use of the vectorial integral representation and the Fresnel formulas of refraction. The electric and magnetic vectors are calculated in the image space; from these, the energy densities and the Poynting vector are obtained. Numerical results, calculated for the focal plane and illustrated by diagrams, emphasize the departure from scalar theory. At the limit of small angular apertures, the results approach the scalar theory, i.e., the known Airy pattern.

Abstract: The second Rayleigh–Sommerfeld (RS) diffraction integral, wherein the normal derivative is specified, is evaluated in simple closed form for all axial points when a divergent or convergent spherical wave is incident upon a circular aperture or disk. These evaluations (solutions) are compared with known corresponding solutions of the first RS diffraction integral. These sets of solutions are intercompared with their mean value, i.e., the derived solutions of the Kirchhoff diffraction integral. The three diffraction formulations are shown to be in agreement for incident divergent spherical waves when the source and observation points are equally distant from the aperture or disk. Conversely, for convergent spherical waves, the three formulations are never in exact agreement for focal and observation points located at finite distances from the aperture, though at optical frequencies the relative error at the geometric focal point is vanishingly small. The second RS formulation predicts, in the limit of plane waves incident on a disk, that the axial irradiance is everywhere equal to the incident irradiance, whereas the first RS formulation predicts that the irradiance goes to zero at the back of the disk.