Showing papers on "Image resolution published in 1970"
TL;DR: In this article, the general considerations and principles involved with IR image up-conversion are presented and discussed, the factors that limit the resolution of the upconverted image are analyzed and the merits of three types of optical systems are discussed with regard to resolution and efficiency of upconversion.
Abstract: The general considerations and principles involved with IR image up-conversion are presented and discussed. The factors that limit the resolution of the up-converted image are analyzed and the merits of three types of optical systems are discussed with regard to resolution and efficiency of up-conversion. Several characteristics of six nonlinear crystals are calculated and compared.
68 citations
TL;DR: It is pointed out the applicability of optical Hadamard-transform coding to detector- noise-limited image scanning and approximate signal-to-noise ratio gains over conventional point-by-point scanning for several whole-image multiplex scanning schemes.
Abstract: We point out the applicability of optical Hadamard-transform coding to detector-noise-limited image scanning and give approximate signal-to-noise ratio gains over conventional point-by-point scanning for several whole-image multiplex scanning schemes.
55 citations
TL;DR: In this article, the position of incidence of any detected photon can be found within the limits of the electronic dead time for one and two dimensional x-ray image dissection using a channel multiplier array.
Abstract: Methods of one and two dimensional x-ray image dissection using a channel multiplier array are discussed in which the position of incidence of any detected photon can be found, within the limits of the electronic dead time. Results for one dimensional systems in which spatial resolutions of 50 pm have been achieved and of a prototype two dimensional system having a similar resolution are reported and further developments and alternative methods of dissection are considered.
32 citations
Patent•
07 Jul 1970
TL;DR: An inventory control system for rapidly taking an inventory of items in an array including an optical scanning system which provides an image of variable size of each item in accordance with the number of units of the item in the inventory, a larger image denoting more units, a signal generator which converts the image to a train of electrical signals, a storage device for storing the signals for later use, retrieval apparatus for regenerating the stored signals at a subsequent time, and a display system for displaying and size quantizing the original image as mentioned in this paper.
Abstract: An inventory control system for rapidly taking an inventory of items in an array including an optical scanning system which provides an image of variable size of each item in accordance with the number of units of the item in the inventory, a larger image denoting more units, a signal generator which converts the image to a train of electrical signals, a storage device for storing the signals for later use, retrieval apparatus for regenerating the stored signals at a subsequent time, and a display system for displaying and size quantizing the original image The item identified by its quantized image is checked against a data bank to determine for that item how many units correspond to the particular image size displayed The checking may be automatic or manual, and an automatic print-out may be provided if desired
29 citations
TL;DR: In this article, a method for eliminating the astigmatism of a Czerny-Turner spectrograph is described in which the grating is used in divergent illumination.
Abstract: A method for eliminating the astigmatism of a Czerny-Turner spectrograph is described in which the grating is used in divergent illumination. Expressions are given for the distances of the tangential and sagittal astigmatic images from the camera mirror in terms of the separation between the entrance slit and the collimating mirror and the condition for the elimination of astigmatism is derived. These results are compared with ray tracing data for a practical instrument. Experimental tests of spatial and spectral resolution for an f/15 spectrograph of 06 m focal length are given at wavelengths 5461 and 2800 A. Over a spectral range of 100 A centred on 2800 A a spatial resolution along the slit in excess of 50 cycles mm−1 has been achieved for a flat inclined image plane. For the same spectrograph with the grating in collimated light the spatial resolution is only 3 cycles mm−1.
25 citations
TL;DR: In this article, the phase aberration at position t across the aperture is assumed to have a power law structure function, E{[(?(t)-?(?)]2} = c|t-?|n.
Abstract: Resolution limits and corresponding optimum linear apertures are determined in the presence of phase errors. Let ?(t) be the phase aberration at position t across the aperture; it is assumed that the random process ? has a power law structure function, E{[(?(t)-?(?)]2}= c|t-?|n. Beam tilting caused by the phase error is "removed" (for each sample of ?), then resolution formulas are developed. An approximate analysis is obtained in closed form and yields an optimum resolution proportional to c1/n for O < n < 2. The exact analysis is given for Gaussian ?, and again the optimum resolution is proportional to c1/n. In applications n= 5/3 is of interest, and in the Gaussian case the best obtainable equivalent rectangle resolution is ? ?)/2? (0.975)c3/5 radians with a corresponding optimum linear aperture of 14c-3/5. When long exposures are considered, imaging without removing beam tilting is of interest, and resolution is degraded by a factor of about 2.5 for a linear aperture. Alternatively, in some applications optimum focus as well as beam tilt should be considered, in this case resolution is improved by a factor of about 1.4 (again for n= 5/3). Finally, joint (tilt corrected) optimization over aperture length and taper is treated; however, as one might expect, the use of taper offers negligible resolution improvement.
23 citations
TL;DR: In this paper, a useful expression for the complex amplitude of the reconstructed holographic image is derived, which shows how the reconstructed image is affected by the optical transfer function of the recording media and by the size and shape of the hologram.
Abstract: A useful expression for the complex amplitude of the reconstructed holographic image is derived. This expression shows how the reconstructed image is affected by the optical transfer function of the recording media and by the size and shape of the hologram. Special cases that are studied include perfect film, very good film, Fourier-transform holograms, and large holograms. Detailed solutions for the general case are obtained by assuming a gaussian optical transfer function and either a rectangular hologram aperture or one having gaussian weighting.
18 citations
TL;DR: A multiplex technique is described that can be used in photoelectric observations of dispersed spectra and an application at the solar eclipse (Mexico, 1970) is described.
Abstract: A multiplex technique is described that can be used in photoelectric observations of dispersed spectra. The encoding pattern is a set of pseudo-random binary sequences. The data processing requires a minimum possible number of operations. A special purpose device could give the spectral intensity distribution on-line. An application at the solar eclipse (Mexico, 1970) is described.
16 citations
TL;DR: In this paper, a method of one dimensional X-ray image dissection using a channel multiplier array and giving a spatial resolution of better than 0.2 mm was developed, where electron pulses are collected from the array on a grid of evenly spaced wires which are capacitatively coupled; positional information is then obtained by comparison of the pulses from each end of the condenser chain.
15 citations
Patent•
14 Dec 1970
TL;DR: In this article, a method for producing a photographic record showing the identification of a moving vehicle, its speed, conditions of visibility, date and time is provided, which can be combined for purposes of corroborating the speed of the moving vehicle.
Abstract: A method is provided for producing a photographic record showing the identification of a moving vehicle, its speed, conditions of visibility, date and time. Conditions of visibility are established by periodically making a first photographic record of a target at a selected location along a highway. In one embodiment, identification and speed are established in a second photographic record by simultaneously photographing a vehicle moving along the highway in the vicinity of the target and a radar speed meter indicating the speed of the photographed vehicle. In a second embodiment, identification and speed are established by taking two pictures with the same photographic means of the identical portion of a moving vehicle in the vicinity of the target at a known time interval in order to make up a second photographic record, and measuring the relative sizes of the image of the identical portion of the vehicle in the two pictures; and thereafter calculating the speed of the vehicle by interrelating the time interval and vehicle image sizes with the image size of an object in a picture taken by said photographic means located at a known distance from the object, the object having an actual dimension corresponding to an actual dimension of the portion of the moving vehicle appearing in the second photographic record. The first and second embodiments for establishing identification and speed can be combined for purposes of corroborating the speed of the moving vehicle. Date and time are established by simultaneously photographing in all exposures making up the first and second photographic records date and time means showing the date and time at which the exposures are made.
15 citations
TL;DR: Using Monte Carlo methods gamma -ray scattering in the detector has been studied in relation to its effect on the spatial resolution attainable in gamma cameras and the application of pulse height discrimination to various types of gamma camera is discussed.
Abstract: Using Monte Carlo methods gamma -ray scattering in the detector has been studied in relation to its effect on the spatial resolution attainable in gamma cameras. Gamma-ray energies ranging from 0.10 to 0.67 Mev were considered, with crystal thicknesses between 6.3 and 50.8 mm of NaI(Tl) and 5 to 20 mm of germanium. For a monoenergetic gamma -ray, incident along the axis of a cylindrical detector, the distribution of energy depositions occurring in individual interactions in the detector is given as a function of the perpendicular distance from the incident ray to the location of the interaction. The application of pulse height discrimination to various types of gamma camera is discussed.
TL;DR: In this paper, a pinhole camera system giving time resolved photographs of the x-ray source in an intense plasma discharge is described, where each pinhole projected an image of the source onto a sheet of scintillation plastic which converted the x rays into a visible light image that was photographed with an image convertor camera.
Abstract: A pinhole camera system giving time resolved photographs of the x‐ray source in an intense plasma discharge is described. Each pinhole projected an image of the x‐ray source onto a sheet of scintillation plastic which converted the x rays into a visible light image that was photographed with an image convertor camera. Use of twin pinholes with appropriate filters and scintillator thicknesses provided some spectral resolution. A spatial resolution of 2 mm was achieved with a time resolution of 10 nsec.
Patent•
29 Apr 1970
TL;DR: In this article, a beam-imaging means, which may be a separate electronic lens, or part of the electric field sector deflection arrangement suitably energized, is located in advance of the beam energy aperture, by a distance such that the exit slit of the ion source is imaged in the plane of thebeam energy aperture.
Abstract: To provide for improved energy output and image resolution of Mattauch-Herzog type mass spectrographs, a beam-imaging means, which may be a separate electronic lens, or part of the electric field sector deflection arrangement suitably energized, is located in advance of the beam energy aperture, by a distance such that the exit slit of the ion source is imaged in the plane of the beam energy aperture. A second electronic lens is arranged between the beam energy aperture and the magnetic field sector deflection arrangement, of similar focal length, and arranged to image the target plane of the mass spectrograph at the same plane of the beam energy limiting means, so that the image focused thereon by the first imaging arrangement is received and focused on the target plane by the second electronic lens; the magnetic field sector deflection arrangement is rotated with respect to the electric field sector deflection arrangement by 180* to compensate for the effects of the lenses. The presence of the lenses permits independent adjustment of dispersion angles and energy band width of the ion beams.
Patent•
20 Apr 1970TL;DR: In this paper, an encoder mask with a plurality of tracks having alternate opaque and clear segments for passing sunlight to associated photo cells is used to provide a coded digital output corresponding to the image position and having sub-image resolution, that is, resolution smaller than the image.
Abstract: A sun sensor having an aperture for receiving sunlight and forming an image of the aperture on an encoder mask, the position of the image corresponding to the angle of the sun relative to the sensor. The mask has a plurality of tracks having alternate opaque and clear segments for passing sunlight to associated photo cells which provide in response thereto a coded digital output corresponding to the image position and having sub-image resolution, that is, resolution smaller than the image. Circuit means combines certain bits of the coded output to provide a Gray Code output having the minimum number of bits required for the desired resolution and maximum angle measurement.
01 Mar 1970
TL;DR: In this article, the authors demonstrated image conversion at millimeter wave frequencies using reflection coefficient modulation of a bulk germanium panel, and demonstrated that the modulation can be applied to a variety of applications.
Abstract: Image conversion at millimeter wave frequencies has been demonstrated using reflection coefficient modulation of a bulk germanium panel.
Patent•
IBM1
TL;DR: In this article, reflective or refractive materials are used to recover normally lost object radiation to produce higher spatial frequencies in the reconstructed image, enlarge the effective numeric aperture at relatively long object-to-hologram distances, and improve image resolution.
Abstract: Apparatus for constructing holograms in which reflective or refractive materials are used to recover normally lost object radiation to thereby produce higher spatial frequencies in the reconstructed image, enlarge the effective numeric aperture at relatively long object-to-hologram distances, and improve image resolution. Image intensity is also improved.
TL;DR: The use of multifrequency linear gratings as test objects satisfies the need for a method which measures resolution at all points in the image format and its principal application seems to be for qualitative testing.
Abstract: Testing of coherent optical data processing systems has shown a need for a method which measures resolution at all points in the image format. The use of multifrequency linear gratings as test objects satisfies this need. Quantitative data may be obtained if care is taken to calibrate and linearize the photographic process. However, the method’s principal application seems to be for qualitative testing. A comparison is made between calculated wavefront aberrations and experimental results obtained using linear gratings.
TL;DR: This paper presents experimental horizon profiles of the earth seen from outside the atmosphere, expressed as variations ofradiance with respect to tangential height for the different spectral channels.
Abstract: This paper presents experimental ir horizon profiles of the earth seen from outside the atmosphere. Measurements were made from a capsule which reached 175 km. The attitude was controlled during the whole flight by means of a gyroscopic device. Seven spectral channels were studied, especially: ozone (9.6 μ), CO2 (14–16 μ), the range of atmospheric window (11 μ), and a broad channel (1–50 μ) that was the only one of the first experiment in 1965. The spatial limit of resolution is 0.16°, and the attitude in space of the capsule has been reconstructed with an accuracy equal to 0.05° due to a star mapper. Results are expressed as variations of radiance with respect to tangential height for the different spectral channels.
TL;DR: The beam ratio (reference beam intensity to object beam intensity) which produces maximum contrast photographic reconstructions from double-exposure holographic interferograms was experimentally determined to be 1.2 +/- 0.2.
Abstract: The beam ratio (reference beam intensity to object beam intensity) which produces maximum contrast photographic reconstructions from double-exposure holographic interferograms was experimentally determined to be 1.2 ± 0.2.
TL;DR: In this paper, the error in the estimation of the edge density trace and the line spread function was investigated for low-contrast edges, and an expression was derived for low contrast edges.
Abstract: The evaluation of image quality parameters directly from the image is often required when the imaging system point spread is not known. The derivation of the parameter values from microdensitometer scans across the images of inferred edges in the scene format is a popular technique. This paper presents the results of a study to determine the errors incurred and the simplification that results from making certain approximations in deriving the values of two particular parameters. The measures of image quality sought are "resolution", which is defined as the area under the transfer function, and "passband", which is the area under the square of the transfer function. An expression is derived for low contrast edges which provides a simple relation between the edge density trace and the line spread function which is independent of film gamma, and the error in resolution and passband resulting from its use as an approximation for edges of higher contrast is given. The second approximation considered is due to the practical requirement that the density trace of the edge is truncated. Closed-form edge-density functions derived from transfer functions consisting of weighted superpositions of exponential and gaussian terms were terminated by "visual" inspection and used to evaluate the errors introduced in the computations of the resolution and passband.
TL;DR: In this article, a two-dimensional position sensitive detector of single charged particles is presented. But the system is read out by a scanning electron beam and the spatial resolution is only 30 microns for the lower energies.
Abstract: Multiple diode arrays of the type developed for optical image sensing in vidicon-type TV camera tubes have been investigated as two-dimensional position sensitive detectors of single charged particles. The approximately half-inch square arrays consist of more than 700,000 diffused silicon diodes. The array is read out by a scanning electron beam. With such a system we have observed individual pulses from helium ions alpha particles and fission fragments in the 0.5 to 50 MeV energy range. The spatial resolution of the system is observed to be about 30 microns for the lower energies.
TL;DR: A new technique is proposed for achieving high accuracy using very low spatial frequency sampling and reconstructing a high-resolution binary image of the pupil from a low-resolution grey-level frame, acquired with a solid-state sensor.
Abstract: Current Video-Oculography (VOG) permits multidimensional, drift-free, noninvasive measurement of eye movements, but cannot be used for fine recording of fast eye movements (saccades), which would require high spatial and high temporal resolutions, corresponding to global data rates in the range of 300Mb/s -5-10Gb/s. A new technique is proposed for achieving high accuracy using very low spatial frequency sampling and reconstructing a high-resolution binary image of the pupil from a low-resolution grey-level frame, acquired with a solid-state sensor. A recursive fitting algorithm for eye position detection is also introduced, allowing correct measurements also when the pupil contour is only partially available.