Showing papers on "Image quality published in 1973"
01 Jan 1973
TL;DR: The material in this chapter shows that the area between the MTF and the AIM curves, now called “TQF” or “MTFA” by different people, is a metric that is broadly applicable for general scenes but not necessarily a good metric for specific objects.
Abstract: In earlier material we addressed to the reader our misgivings about the parameters chosen by many systems evaluators. The material in this chapter shows that the area between the MTF and the AIM curves, now called “TQF” or “MTFA” by different people, is a metric that is broadly applicable for general scenes but not necessarily a good metric for specific objects.
46 citations
TL;DR: In certain applications, especially x-ray and gamma-ray photography, pinhole cameras provide one of the only methods of producing sharp images, providing theautocorrelation function of the array is sharply peaked.
Abstract: In certain applications, especially x-ray and gamma-ray photography, pinhole cameras provide one of the only methods of producing sharp images. To increase the image quality, the use of an array of multiple pinholes is found valuable. The resulting blurred image must then be decoded. A particularly direct method of decoding using the original array of pinholes is possible, providing theautocorrelation function of the array is sharply peaked. Preliminary results with representative arrays are discussed.
27 citations
TL;DR: The Mertz and Gray analysis of image scanning in terms of multidimensional Fourier transforms is reformulated using a different coordinate system, leading to scanning equations that emphasize the importance of the scanning apertures.
Abstract: The Mertz and Gray analysis of image scanning in terms of multidimensional Fourier transforms is reformulated using a different coordinate system. A simplified mathematical notation is used for this analysis leading to scanning equations that emphasize the importance of the scanning apertures. Other image processes involving scanning are described in terms of their multidimensional Fourier transforms. These include a novel two-dimensional screening technique, and its comparison with a simple screening method and with conventional photographic screening processes. The effect on video spectra of aperture filtering and an analysis of television line interlacing are also given. The conditions for the validity of the unidimensional analysis of some of these image processing systems are indicated.
24 citations
TL;DR: The surfaces of large (approximately 1-m) diffusely reflecting objects can be mapped by automatic following of the holographic real image of the object by using a sinusoidal optical interference pattern projected onto the object when the hologram is taken.
Abstract: The surfaces of large (approximately 1-m) diffusely reflecting objects can be mapped by automatic following of the holographic real image of the object. Large aperture, low f number holograms give the shallow depth of focus required for this method. The ability to apply the technique to situations requiring a pulsed laser is demonstrated. Unity magnification real images from holograms made with a Q-switched ruby laser have a measured metric fidelity of at least one part in 104 over an object field of 60 deg. A sinusoidal optical interference pattern projected onto the object when the hologram is taken provides the type of contrast pattern necessary for unambiguous determination of the location of the focused image surface and facilitates automatic focus detection. The image is scanned by an image dissector that is moved about the image by a 3-axis slide system. A computer analyzes the video signals, directs the machine motions to follow the image, and provides an output of surface dimensions in digital form. A prototype machine using cw helium–neon lasers for object illumination and image reconstruction is described and performance data presented.
11 citations
TL;DR: A method is suggested for inserting viewer criteria directly into coding algorithms; any complex visual model may be used and the first-order entropy of the DPCM signal can be reduced by 30 percent for a high-detail picture with only a small reduction in picture quality.
Abstract: A method is suggested for inserting viewer criteria directly into coding algorithms; any complex visual model may be used. The technique is applied to a DPCM-type coder, and a number of variations are compared on the basis of entropy, quality, and complexity. It is found that, using a simple one-dimensional filter model, the first-order entropy of the DPCM signal can be reduced by 30 percent for a high-detail picture with only a small reduction in picture quality. Furthermore, by means of a single threshold control, one can efficiently trade off bit-rate and picture quality over a large range for use in adaptive strategies.
10 citations
01 Mar 1973
TL;DR: In this article, an edge definition criterion is proposed for overcoming image unsharpness effects in taking accurate diametral measurements from radiographs, and an electronic density slicing method for automatic edge definition is described.
Abstract: Means of obtaining improved dimensional measurements from neutron radiographs of nuclear fuel elements are discussed. The use of video-electronic image analysis relative to edge definition in radiographic images is described. Based on this study, an edge definition criterion is proposed for overcoming image unsharpness effects in taking accurate diametral measurements from radiographs. An electronic density slicing method for automatic edge definition is described. Results of measurements made with video micrometry are compared with scanning microdensitometer and micrometric physical measurements. An image quality indicator for estimating photographic and geometric unsharpness is described.
9 citations
TL;DR: The unusual transfer function characteristics of the SAS are shown to obtain larger sampling distances than those required by the Whittaker-Shannon sampling theory.
Abstract: This paper discusses the application of a synthetic aperture system (SAS) for the formation of infrared, images The SAS of primary interest is a hexagoiial array of six circular apertures; special emphasis is placed on a one-dimensional model that describes the salient features of the two-dimensional model In infrared images, in the 8–14-μm region, conventional detectors are too large to sample the image without aliasing the spatial spectrum The unusual transfer function characteristics of the SAS are shown to obtain larger sampling distances than those required by the Whittaker-Shannon sampling theory One possible detector array that will correctly sample the image is presented
8 citations
TL;DR: A model of visual performance is presented that has predictive capabilities over a wide range of situations, when used in conjunction with objective performance data relating to visual aids and the optics of the eye.
Abstract: When vision through an optical aid is being considered it is desirable to know something of the effect of the optical quality of the aid on performance. Methods of image evaluation are discussed with particular reference to visual aids. All major methods of image evaluation are distinctly limited in predictive capability when the human observer is the final element in the chain. A model of visual performance is presented that has predictive capabilities over a wide range of situations, when used in conjunction with objective performance data relating to visual aids and the optics of the eye.
7 citations
TL;DR: In this article, the U.S. Geological Survey (USG.G.S) developed methodologies for predicting the imaging capabilities of photogrammetric camera systems, comparing conventional systems with new or different types of systems, and analyzing the image quality of photographs.
6 citations
28 Feb 1973
TL;DR: The research program has as its primary purpose the analysis and development of techniques and systems for efficiently generating, processing, transmitting, and displaying visual images and two dimensional data arrays.
Abstract: : The research program has as its primary purpose the analysis and development of techniques and systems for efficiently generating, processing, transmitting, and displaying visual images and two dimensional data arrays. Research is oriented toward digital processing and transmission systems. Five task areas are reported on: (1) Image Coding Projects: the investigation of digital bandwidth reduction coding methods; (2) Image Restoration and Enhancement: the improvement of image fidelity and presentation format; (3) Image Data Extraction Projects: the recognition of objects within pictures and quantitative measurement of image features; (4) Image Analysis Projects: the development of quantitative measures of image quality and analytic representation; (5) Image Processing Support Projects: development of image processing hardware and software support systems.
5 citations
16 Apr 1973
TL;DR: The purpose of this paper is to describe the image processing research at MIT and to present some qualitative considerations about picture quality as mentioned in this paper, which is the same as the purpose of the paper in this paper.
Abstract: The purpose of this paper is to describe the image processing research at MIT and to present some qualitative considerations about picture quality.© (1973) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: Results showed that hypocycloidal motion degrades the input to the imaging system considerably, implying that an imaging system of high resolution may not be necessary to obtain tomograms of diagnostic quality.
Abstract: A method of measuring the one-dimensional input x-ray pattern of a bone phantom exposed with tomographic motion was used to study image quality in laminagraphy. Results showed that hypocycloidal motion degrades the input to the imaging system considerably, implying that an imaging system of high resolution may not be necessary to obtain tomograms of diagnostic quality.
TL;DR: Several types of speckle-free modulation have been investigated which appear to provide high redundancy for continuous-tone transparencies with coherent light.
TL;DR: A dramatic reduction in image distortion resulting from turbulent water has been demonstrated using speckle reference holography, demonstrating that the holographic technique eliminates most image distortion.
Abstract: A dramatic reduction in image distortion resulting from turbulent water has been demonstrated using speckle reference holography. Conventional photographs taken simultaneously over the same path clearly show that the holographic technique eliminates most image distortion.
TL;DR: In this paper, it is shown from test object and clinical radiographs that the image quality of Class I detail is affected mainly by the optical properties of the system and the image image quality is affected by quantum mottle, and therefore the system MTF as well as receiver operating characteristic (ROC) curves are needed to evaluate radiographic image quality.
Abstract: The quality of radiographic images recorded by screen-film systems depends on the contrast and shape of the image detail which is of diagnostic interest. As a first approximation, the complex world of radiographic detail can be divided into two categories, one containing high contrast, inherently sharp detail (Class I), and the other containing low contrast, inherently unsharp detail (Class II). It is shown from test object and clinical radiographs that the image quality of Class I detail is affected mainly by the optical properties of the system and the image quality of Class II detail by quantum mottle. Therefore, the system MTF as well as receiver operating characteristic (ROC) curves are needed to evaluate radiographic image quality.
Patent•
24 Aug 1973TL;DR: In this article, an imaging system consisting of a scanning illumination source to illuminate an object field and a real-time thresholding photoelectric transducer is provided for environments where light scattering reduces image quality.
Abstract: An imaging system is provided for environments where light scattering reduces image quality. The imaging system comprises a scanning illumination source to illuminate an object field. A first photoelectric transducer converts a focused image of the illuminated object field to an electric analog. A second realtime thresholding photoelectric transducer is physically and electrically connected to the first transducer to recreate an optical image of the object field having electrical analog values in excess of a predetermined value. Utilization of the optical output from the second transducer is by conventional optical or electro-optical systems.
DOI•
20 Feb 1973TL;DR: S Snyder as discussed by the authors discusses the problem of determining the quality of an image produced by a line-scanning system with the advent of low-light-level television and infrared imaging systems formilitary aircraft.
Abstract: VIDEO IMAGE QUALITY AND FACIAL RECOGNITIONHarry L. Snyder, Ph.D.Virginia Polytechnic InstituteIntroductionThe problem of determining the quality ofan image produced by a line -scanning systemreceived increased attention in the early1960's with the advent of low -light -leveltelevision and infrared imaging systems formilitary aircraft. In addition, the interestin manned lunar exploration, with the attend-ant need for better evaluation of the lunarsurface, made necessary the telemetering ofimage data by such systems as Lunar Orbiterand Surveyor. An understanding of imagequality became more critical once it was real-ized that digitizing of the video signal fortransmission introduced a different form ofnoise (the so- called "striping ") into thevideo signal. As a result of these severalmore -or -less simultaneous needs, research intothe nature of line -scan image quality and itseffect upon image interpretability was begunabout 1961, and has continued through thepresent.The early studies focussed upon the re-
Journal Article•
TL;DR: In this paper, the authors evaluated the performance of the I2S Mark I MULTI- SPECTRAL CAMERA and the PARAMETERS in terms of image quality and showed that an accuracy in the NEIGHBORHOOD of PLUS or MINUS 3 percent ABSOLUTE GROUND ReFLECTION could be achieved by the system.
Abstract: UNDER A USGS-EROS GRANT THE UNIVERSITY OF WASHINGTON HAS ACQUIRED AN INTERNATIONAL IMAGING SYSTEM (I2S) MARK I MULTI- SPECTRAL CAMERA. A PRELIMINARY EXAMINATION OF THE PHOTOGRAPH SHOWED IMAGE QUALITY VARIATIONS OF SUCH AN EXTENT THAT THE DATA WERE OF QUESTIONABLE VALUE FOR ACCURATE TONAL ANALYSIS. AS A CONSEQUENCE IT WAS DECIDED TO RE-EXAMINE THE IMAGING SYSTEM AND THE PARAMETERS AFFECTING IMAGE QUALITY. AFTER CALIBRATION AND WITH THE AID OF AN IDEALIZED ATMOSPHERIC MODEL, THE RELIABILITY OF THE RADIOMETRIC MEASUREMENTS WAS CONSIDERABLY INCREASED. A FIRST TEST SHOWED THAT AN ACCURACY IN THE NEIGHBORHOOD OF PLUS OR MINUS 3 PERCENT ABSOLUTE GROUND REFLECTION COULD BE ACHIEVED BY THE CALIBRATED SYSTEM.
TL;DR: In this article, a comprehensive study on the correlation of physical parameters with the psychometric judgment values in regard to photographic images has been attemtped, and it has been shown that there is no unique correspondences between any one ofthe physical parameters that we considred.
Abstract: — A comprehensive study on the correlation of physical parameters with thepsychometric judgment values in regard to photographic images has been attemtped. It has been?shown that there is no unique correspondences between the psychometric value and any one ofthe physical parameters that we considred. Two different combinations of physical parameters?have been suggested as reliable guides for specifying the psychometric figure of merit. Theresults show how closely the proposed combinations correspond to the over all picture quality?values of photographic images.
01 Jan 1973
TL;DR: This experiment was an analysis of the difference in objective measures of image quality between chemical and physical development methods, including prefixation and postfixatiorr processes, including postfixation physical development.
Abstract: This experiment was an analysis of the difference in objective measures of image quality between chemical and physical development methods, including prefixation and postfixatiorr processes . Of particular interest was the process outlined by Matejec for postfixation physical development. An investigation of resolving power and MTF for two fine grain films was carried out for four different development processes all possessing approximately the same speed capability. Both the effect of combined chemical and optical spread functions and the chemical spread alone were investigated through edge analysis using Fourier
01 Sep 1973
TL;DR: In this paper, image quality criteria are defined and mathematically formulated for the prediction computer program which is to be developed for the Viking lander imaging experiment. And the general goal to encompass, but not exceed, the range of the scene radiance distribution within single, commandable, camera dynamic range setting is also considered.
Abstract: Image quality criteria are defined and mathematically formulated for the prediction computer program which is to be developed for the Viking lander imaging experiment. The general objective of broad-band (black and white) imagery to resolve small spatial details and slopes is formulated as the detectability of a right-circular cone with surface properties of the surrounding terrain. The general objective of narrow-band (color and near-infrared) imagery to observe spectral characteristics if formulated as the minimum detectable albedo variation. The general goal to encompass, but not exceed, the range of the scene radiance distribution within single, commandable, camera dynamic range setting is also considered.