Showing papers on "Image plane published in 1971"

Shearing interferometer using the grating as the beam splitter.

Abstract: The theoretical interpretation of the shearing interferometer based on the moire method using the fourier image of the grating is described. To obtain a pattern with good contrast, the observing plane must coincide with the normal fourier image plane of the grating or with the reversed fourier image plane. The information obtained by this method is the first partial derivative and under certain conditions the second partial derivative of the distortion from the reference wavefront, which is planar or spherical. Applications to measurement of the phase gradient and lens aberration are shown.

Light scanning and printing system

Abstract: A light scanning system of controlled spot motion variation perpendicular to the direction of scan utilizing a rotating mirror and two cylindrical or toroidal lenses positioned relative to the rotating mirror to allow increased nominal axis of rotation to facet angular tolerances while maintaining a distinct non-overlapping line scan. Specifically, for one application the axis of rotation of the mirror is orthogonal to the plane formed by the incoming and reflected beam from the mirror. The first cylindrical or toroidal lens, which has little or no power in the scan plane, focuses the incoming beam in the azimuth perpendicular to the scan onto the mirror while the second cylindrical lens acts as a beam configurer to configure the beam to substantially collimated shape while directing it towards a spherical lens for focusing onto an image plane.

Infrared receiver for optical radar

Abstract: There is disclosed a receiver for an optical radar utilizing a two-dimensional array of microlens image dissectors which completely fills an area of an image plane. Each microlens is directly coupled to a mixer-detector element. The array is adapted to be illuminated with returned focus radiation from a remote reflecting target and with a planar wave of optical energy from a local oscillator. The output signals of the mixer-detectors are analyzed and utilized to orientate the array such that the maximum amplitude output signal corresponds to the central microlens of the array.

Optical field curvature corrector

Abstract: The invention is a device utilizing one or more carefully oriented optical prisms to alter the optical path length of a converging radiant-energy-ray bundle between the lens and the image plane of an optical system and to effect a focal correction in the information which may be collected through sequential scanning of the image plane.

Optical system for focusing spaced object planes in a common image plane

Abstract: An optical system for focusing spaced object planes into a common image plane by means of a compensating optical element alternately placed and removed from between an objective and the object planes which equalizes the optical paths thereof.

Holographic interferometry employing image plane holograms

Abstract: A hologram of a test specimen is formed in an optical arrangement including a lens which focuses coherent light reflected by the object onto a photographic plate. A real-time interferometric analysis of the deformation of the object as a result of loading is made using the resulting image-plane hologram. The interference fringe frequency in particular area resulting from gross deformation of the object is decreased to allow the detection of fringe anomalies in that area by suitable translations of the hologram relative to the reconstruction beam. In an alternate embodiment, a pair of image-plane holograms of the object at two states of loading are formed on the same photographic plate by a double-exposure technique using reference beams which bear different angles to the photographic plates during the two exposures. To reconstruct the holograms a pair of reconstruction beams are employed and motion of the beams relative to one another allows the fringe frequency on various areas of the object to be modified.

Diffrimoscopic Image Formation under Partially Coherent Illumination (Slits and Opaque Strips)

Abstract: Intensity distributions in diffrimoscopic images have been derived for rectangular objects like slits and opaque strips under partially coherent illumination. The illuminating slits, objects, obstructions and apertures are assumed to be of infinite length in one direction and of finite width perpendicular to it. Therefore the mathematical treatment reduces to that of one dimension. Expressions representing the complex amplitudes and the intensity distribution in the image plane have been suitably split to show separately the interfering effect of one edge over the other and the effect of partial coherence. The centre of the dark fringe does not always coincide with the geometric image of the edge. The relative shifts between them have been shown to vary almost linearly with the degree of coherence. The effect of the degree of coherence upon the intensities at the geometric image of the edge and at the centre of the image has been discussed. The effects of the widths of obstructions, aperture and objects u...

Facsimile and microfilm apparatus

Abstract: The disclosed embodiment of the present invention is a facsimile and microfilm apparatus for simultaneously recording photographically on a strip of microfilm and a strip of photosensitive paper. A beam splitter is employed for projecting an image from an object plane onto a strip of photosensitive paper at an image plane. An optical system and film drive system mounted behind the beam splitter is employed with a shutter as a microfilm camera and with an illumination source as a microfilm projector. When employed as a camera, the photosensitive paper forms an object plane for photographically recording an image of the original object on microfilm. When employed as a projector, the photosensitive paper forms an image plane for recording the information contained on the developed film strip onto the photosensitive paper. A second beam splitter mounted in front of the projector is employed for viewing the film strip through an eyepiece so that the operator can select the appropriate frame on the film strip.

Optical spatial frequency filter

Abstract: IN AN OPTICAL SYSTEM FOR FORMING A REPRESENTATION OF A SCENE AT AN IMAGE PLANE, A WEDGE STRUCTURE OF OPTICAL QUALITY MATERIAL IS DISPOSED BETWEEN THE SCENE AND THE IMAGE PLANE. THE LIGHT PASSING THROUGH DIFFERENT SECTIONS OF THE WEDGE STRUCTURE IS DEFLECTED IN DIFFERENT DIRECTIONS, FORMING A PLURALITY OF DISPLACED IMAGES AT THE IMAGE PLANE. THE SUMMATION OF THE VARIOUSLY DISPLACED IMAGES RESULTS IN A MODULATION TRANSFER FUNCTION EXHIBITING SUBSTANTIAL ATTENUATION OF THE SPATIAL FREQUENCY COMPONENTS WITHIN A PREDETERMINED FREQUENCY RANGE. THE WEDGE IS DESIGNED AND ORIENTED TO PRODUCE ANGULAR DEFLECTIONS WHICH YIELD SPECIFIC DISPLACEMENTS OF THE IMAGES AND A CORRESPONDING SPATIAL FREQUENCY REJECTION BAND. THE FILTER MAY BE USED TO AVOID ALIASTING IN COLOR TELEVISION CAMERAS HAVING STRIPED COLOR MODULATING GRATINGS BY UTILIZING THE WEDGE TO INSURE HIGH ATTENUATION IN THE VICINITY OF THE SPATIAL MODULATION FREQUENCY PRODUCED BY THE STRIPED COLOR GRATINGS. D R A W I N G

Super-wide angle photographic objective

Abstract: A ten group, twelve element, super-wide angle photographic objective lens which corrects chromatic aberration over the whole image plane to be used and to obtain an aberration condition balanced therewith.

The Influence of the Radiation Spectrum Bandwidth on the Resolution of an Image Up-Converter

Abstract: The influence of the infra-red spectrum bandwidth on the transverse resolution of an image up-converter is investigated. It is shown that by suitable placing of the infra-red image plane, the deterioration of the resolution due to the infra-red spectrum bandwidth does not occur.

Phase Aberrations in Bragg Imaging

Abstract: Theoretical investigations of Bragg imaging in three dimensions show that a cylindrically convergent light beam reconstructs each plane wave component of the sound field unambiguously. However, aberrations in the image plane arise for those sound components that project out of the plane normal to the line formed by the light. Particularly it is shown that images from long objects oriented parallel to the convergence of the light beam are free from significant phase aberrations (i.e., the components at the image plane have essentially the same phase with respect to each other as the associated sound components). However, similar analysis and experiments show that images of objects oriented at right angles to this direction do indeed have a significant phase aberration.

Weather time display

Abstract: A weather-time display, such as for use in a closed-circuit of cable television system, includes a plurality of sensors for producing signals proportional to a corresponding plurality of selected environmental parameters. Those signals are sequentially applied to a meter to which a rotatable mirror is coupled. An image of an indicator is projected onto that mirror and from there it is reflected onto an image plane located at the viewing plane of a video camera. Images of scales calibrated in units appropriate to the sensed parameters are sequentially superimposed with the image of the indicator at the image plane such that sequential composite images of the scales and the indicator are formed for viewing and transmission by the video camera. If desired, and as herein shown, an image of the time may also be superimposed on the composite scale-indicator image at the image plane.

Optical ranging device

Abstract: A thin interrupter is moved through the image plane of a converging optical system to interrupt light impinging on a pair of equal size detectors The output signals from the detectors are used as a measure of the distance between the light source or target and the lens and the optical system

Method and apparatus forming plural focused images with a common lens system

Abstract: Method and apparatus for focusing a selected portion of an object at a conjugate plane different from the conjugate plane of focus of other portions of the object. A focus change member made of a material having a refractive index different from that of air is placed adjacent the object, which may be a film negative or transparency. The portion of the object which is covered by the focus change member appears to lie closer to the focusing lens than does the uncovered portion of the object, so that the lens projects the focused image of the portion covered by the focus change member to a greater distance than the focused image of the uncovered portion of the object. A technique is also described for photographically enlarging an object to obtain discrete areas of dissimilar magnification on an image plane, and to obtain a magnification which is variable along a dimension of the image plane.

Coherence in the Image Plane of an Incoherent System

Abstract: Coherence in the image plane of an optical system depends on the conditions of illumination and the impulse response of the optical components. The propagation of the mutual intensity function from object to image plane is evaluated for various conditions. Experimental measurements verify an increase of coherence under conditions where the mutual intensity function in the object plane is not resolved. These considerations demonstrate the requirement for quality in condenser optical components and care when imaging components are cascaded.

Elimination of Coherent Noise in a Coherent Light Imaging System

Abstract: Optical imaging systems using coherent light introduce objectionable noise into the output image plane. Dust and bubbles on and in lenses cause most of the noise in the output image. This noise usually appears as bull's-eye diffraction patterns in the image. By rotating the lens about the optical axis these diffraction patterns can be essentially eliminated. The technique does not destroy the spatial coherence of the light and permits spatial filtering of the input plane.

Large-picture camera

Abstract: A large-picture camera for producing a positive photographic picture of an object especially a human being, in essentially natural size, comprises means for supporting a positive photographic material at an image plane which is adjacent a pickup area, a reflective objective constituted by a concave reflector for forming an image of the object positioned at the pick-up area in the image plane, illuminating means including at least one flashlamp arranged to illuminate the object at the pick-up area, second supporting means for adjustably supporting the reflector in opposed relationship to the pick-up area, and the adjacent first supporting means such that an object at the pick-up area is imaged by the reflective objective at the image plane. Screen means prevent any substantial amount of light stemming from the illuminating means from arriving at the image plane via any other path than via the reflective objective.

Influence of Partially Spatially Coherent Illumination on the Measurement of Two-dimensional Correlation Function†

Abstract: A coherent optical filtering is often applied to the measurement of correlation function of two-dimensional patterns. The present report treats the influence of spatial coherence on such an optical filtering. A general formula for optical filtering with partially spatially coherent illumination is obtained. The intensity distribution of correlation in the output image plane for several special cases is calculated, where different kinds of coherence conditions of illumination in the process of holographic recording of a filter, or of filtering are assumed. An experiment is performed to verify the theory.

Illumination optical system for projecting multi-photographic image

Abstract: An illumination optical system for projecting multi-photographic images wherein the illumination light loss is minimized is provided by disposing a group of micro-lenses substantially similar to that used in the photographing optical system in the of and backwardly of an image plane; or displacing an illumination light source relative to said image plane in plane symmetrical relation with a movable photographing aperture; or disposing a light diffusion plate between said image plane and said micro-lens group; or disposing photographing and projection condenser lenses in symmetrical relation with respect to said image plane; or disposing the light source and the aperture in point symmetrical relation with respect to the center of said image plane; or positioning the light source relatively closer to said image plane; or focusing the optical image of the light source forwardly of the image plane after the light beams have passed through the image plane.

Image-region fields for a stepped reflector

Abstract: A method is presented for the calculation of the field in the image space of a stepped reflector, when the incident field is a plane wave inclined at an angle to the reflector axis. Each field component is obtained as a Fourier series in the azimuthal variable of the image plane.

Computer simulation of the performance of advanced underwater optical viewing systems

Abstract: A simulation model has been formulated for the parametric analysis of the capabilities of advanced underwater viewing systems and to facilitate the comparison of the different systems The water medium is characterized in the model by the absorption coefficient, a , the scattering coefficient, s , the volume scattering function, \sigma , and the polarization coefficient, \psi_{p} , of the backscattered light Monte Carlo techniques are used to calculate effective attenuation coefficients for illuminating, image-forming, and backscattered light These coefficients permit the most significant effects of multiple scattering to be incorporated into the model The output of the simulation is the expected signal and backscattered irradiance functions across a strip in the image plane of the receiver

The design and construction of kaleidoscopes to modify the energy distribution in the image plane of the AWRE arc image furnace

Abstract: The energy distribution in the focal space of any image furnace is not uniform. For target irradiation purposes a uniform flux density is required over an area that may lie between 1 and 100 cm2. The polygonal lightpipe or kaleidoscope is a convenient method for averaging out a non-uniform flux distribution over a square or rectangular target. The general principles behind a particular application are discussed in relation to the AWRE argon arc image furnace.

A hardware approach to acoustic imaging

Abstract: Three basic approaches to acoustic imaging are described: focused imaging, which uses acoustic lenses or reflectors to form an image; holographic imaging, which reconstructs images from detected wavefronts; and high-resolution beamforming imaging, which maps the object plane into the image plane by scanning. For each system type, possible hardware implementations are described with specific examples of existing systems. In addition, problems associated with each technique are discussed.

Detecting device for focusing in optical instrument

Abstract: A plurality of photoelectric elements connected in series to each other are arranged on an image plane through an objective lens of an optical instrument, a variable divided voltage of a separate electric source is loaded across said photoelectric elements connected in series for arranging the output voltage of said photoelectric elements connected in series to each other to hold it near on zero voltage, and a galvanometer connected across said photoelectric elements connected in series detects the minimum voltage for detecting a focusing point of an object on the image plane through the objective lens, by changing the spacing between the lens and the image plane.

Some analytical investigations of phase contrast imaging

Abstract: An analytical study of phase contrast imaging is performed. It is shown that the complex disturbance in the image plane can be represented as a convolution of the object disturbance and the Fourier transform of the transmission function of the phase plate. The simple theory of the phase contrast microscope is then derived as a limiting case of this more general result that is applicable when the size of the phase object is small compared to the area of the entrance aperture of the system. The response of a general system to several simple large phase objects is also examined, and it is shown that qualitative information about these objects can be obtained from the intensity pattern when the phase perturbations are small, providing the background is sufficiently uniform, and the size of the phase spot on the phase plate is carefully chosen. The study provides insight into the type of performance that can be achieved, for example, if phase contrast imaging is used to extract phase information from an optical memory or if it is used as an experimental tool to study the qualitative behavior of such phenomena as clear air turbulence.