It is widely appreciated that the faithfulness in estimation of an unknown object depends strongly upon what is known a priori about the object. In particular, the knowledge that any object must be positive, called "positivity,” has been well exploited in both restoration schemes1-4 and reconstruction schemes.5-8 Positivity, specifically, produces the benefit of sharper edge gradients where the edge meets the known (or zero) background level,9 the extent where the gradient profile contains spatial frequencies that may exceed appreciably the cutoff frequency in the data.3,4
{"title":"Maximum Bounded Entropy: a New Method of Tomographic Reconstruction","authors":"B. Frieden, C. Zoltani","doi":"10.1364/iact.1984.tua4","DOIUrl":"https://doi.org/10.1364/iact.1984.tua4","url":null,"abstract":"It is widely appreciated that the faithfulness in estimation of an unknown object depends strongly upon what is known a priori about the object. In particular, the knowledge that any object must be positive, called \"positivity,” has been well exploited in both restoration schemes1-4 and reconstruction schemes.5-8 Positivity, specifically, produces the benefit of sharper edge gradients where the edge meets the known (or zero) background level,9 the extent where the gradient profile contains spatial frequencies that may exceed appreciably the cutoff frequency in the data.3,4","PeriodicalId":133192,"journal":{"name":"Topical Meeting on Industrial Applications of Computed Tomography and NMR Imaging","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122374902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Tutorial on Reconstruction on Families of Curves","authors":"A. Cormack","doi":"10.1364/iact.1984.tud1","DOIUrl":"https://doi.org/10.1364/iact.1984.tud1","url":null,"abstract":"Summary not available.","PeriodicalId":133192,"journal":{"name":"Topical Meeting on Industrial Applications of Computed Tomography and NMR Imaging","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126883753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A transmission electron microscope operating in the 100kV range has been designed to perform three dimensional analysis of relatively thick specimens. Specimens can be up to 8mm in diameter and over one micrometer thick, so that the third dimension is useful at sub-micron resolutions. We call our technique microtomography.
{"title":"True 3-D Transmission Electron Microscopy","authors":"A. Nelson","doi":"10.1364/iact.1984.mc6","DOIUrl":"https://doi.org/10.1364/iact.1984.mc6","url":null,"abstract":"A transmission electron microscope operating in the 100kV range has been designed to perform three dimensional analysis of relatively thick specimens. Specimens can be up to 8mm in diameter and over one micrometer thick, so that the third dimension is useful at sub-micron resolutions. We call our technique microtomography.","PeriodicalId":133192,"journal":{"name":"Topical Meeting on Industrial Applications of Computed Tomography and NMR Imaging","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122939274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Both an advantage and a limitation of current nuclear magnetic resonance techniques is the sensitivity of relaxation times to various chemical and physical environmental conditions. Thus accurate determination of flow is foiled by the similar order of magnetude sensitivity of relaxation measurements to molecular oxygen concentrations. Resolution of the ambigarty that results would occur if it were possible to perform measurements far more sensitive to molecular environment effects and less so to physical factors. Unpaired electrons and spectra that can be gathered from them electron spin responce spectra - fulfill this criterion. Not only do they allow resolution of ambiguities from high spatial resolution nuclear magnetic resonance scans but promise chemically and physiologically interesting measurements in and of themselves.
{"title":"In Vivo Tissue Measurements with an Imaging Electron Spin Resonance Spectrometer","authors":"H. Halpern, A. Nelson, B. Teicher","doi":"10.1364/iact.1984.md5","DOIUrl":"https://doi.org/10.1364/iact.1984.md5","url":null,"abstract":"Both an advantage and a limitation of current nuclear magnetic resonance techniques is the sensitivity of relaxation times to various chemical and physical environmental conditions. Thus accurate determination of flow is foiled by the similar order of magnetude sensitivity of relaxation measurements to molecular oxygen concentrations. Resolution of the ambigarty that results would occur if it were possible to perform measurements far more sensitive to molecular environment effects and less so to physical factors. Unpaired electrons and spectra that can be gathered from them electron spin responce spectra - fulfill this criterion. Not only do they allow resolution of ambiguities from high spatial resolution nuclear magnetic resonance scans but promise chemically and physiologically interesting measurements in and of themselves.","PeriodicalId":133192,"journal":{"name":"Topical Meeting on Industrial Applications of Computed Tomography and NMR Imaging","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124899938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We address the problem of industrial materials inspection using computed tomography. Of particular interest is the possibility of checking for defects when there are only a few measured projections. This situation may arise because of physical restrictions on the geometry of the projection collection apparatus, or from a desire to provide rapid measurement and reconstruction in a routine inspection mode.
{"title":"Industrial Materials Inspection Using Computed Tomography with Few Views","authors":"P. Heffernan, R. Robb","doi":"10.1364/iact.1984.mb3","DOIUrl":"https://doi.org/10.1364/iact.1984.mb3","url":null,"abstract":"We address the problem of industrial materials inspection using computed tomography. Of particular interest is the possibility of checking for defects when there are only a few measured projections. This situation may arise because of physical restrictions on the geometry of the projection collection apparatus, or from a desire to provide rapid measurement and reconstruction in a routine inspection mode.","PeriodicalId":133192,"journal":{"name":"Topical Meeting on Industrial Applications of Computed Tomography and NMR Imaging","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127826806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Tutorial on Survey of Non-Medical Applications of Computed Tomography","authors":"Richard Gordon","doi":"10.1364/iact.1984.ma1","DOIUrl":"https://doi.org/10.1364/iact.1984.ma1","url":null,"abstract":"Summary not available.","PeriodicalId":133192,"journal":{"name":"Topical Meeting on Industrial Applications of Computed Tomography and NMR Imaging","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128972357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nuclear Magnetic Resonance Imaging (NMRI) is based on a fundamental relationship in NMR: where ω is the resonant frequency (in radian/sec), ɣ is the gyromagnetic ratio, and H is the magnetic field strength. Application of a linear field gradient across a sample, therefore, gives rise to a spatially dependent distribution of NMR frequencies.
{"title":"Concepts and Nonmedical Applications of NMR Imaging","authors":"W. Rothwell, P. Gentempo","doi":"10.1364/iact.1984.md1","DOIUrl":"https://doi.org/10.1364/iact.1984.md1","url":null,"abstract":"Nuclear Magnetic Resonance Imaging (NMRI) is based on a fundamental relationship in NMR: where ω is the resonant frequency (in radian/sec), ɣ is the gyromagnetic ratio, and H is the magnetic field strength. Application of a linear field gradient across a sample, therefore, gives rise to a spatially dependent distribution of NMR frequencies.","PeriodicalId":133192,"journal":{"name":"Topical Meeting on Industrial Applications of Computed Tomography and NMR Imaging","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134373469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Séguin, P. Burstein, P. Bjorkholm, F. Homburger, R. Adams
A high-resolution, low-dose, tomographic x-ray scanner for small objects is being developed for use as a tool in in vivo clinical tests of substances suspected of being carcinogenic. In such tests a large group of animals (typically mice) is exposed to the substance in question, and the animals are then inspected at specified intervals for tumor growth. Non-destructive methods of inspection are desirable, and tomographic x-ray imaging is a natural possibility.
{"title":"High-Resolution Tomography of Small Laboratory Animals*","authors":"F. Séguin, P. Burstein, P. Bjorkholm, F. Homburger, R. Adams","doi":"10.1364/iact.1984.mc5","DOIUrl":"https://doi.org/10.1364/iact.1984.mc5","url":null,"abstract":"A high-resolution, low-dose, tomographic x-ray scanner for small objects is being developed for use as a tool in in vivo clinical tests of substances suspected of being carcinogenic. In such tests a large group of animals (typically mice) is exposed to the substance in question, and the animals are then inspected at specified intervals for tumor growth. Non-destructive methods of inspection are desirable, and tomographic x-ray imaging is a natural possibility.","PeriodicalId":133192,"journal":{"name":"Topical Meeting on Industrial Applications of Computed Tomography and NMR Imaging","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127704359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In many cross-sectional imaging situations, the object is axisymmetric, ie, a function of radius alone. Examples include plasma spectroscopy and refractive index profiling of optical fibers. In such cases, one projection suffices for reconstruction, and the object f(r) and projection g(R) are related by the Abel transform pair [1]: (1) (2) where prime denotes differentiation.
{"title":"Abel Inversion from Noisy Data: An Optimal Filtering Approach","authors":"E. Hansen, Phain-Lan Law","doi":"10.1364/iact.1984.tuc4","DOIUrl":"https://doi.org/10.1364/iact.1984.tuc4","url":null,"abstract":"In many cross-sectional imaging situations, the object is axisymmetric, ie, a function of radius alone. Examples include plasma spectroscopy and refractive index profiling of optical fibers. In such cases, one projection suffices for reconstruction, and the object f(r) and projection g(R) are related by the Abel transform pair [1]: (1) (2) where prime denotes differentiation.","PeriodicalId":133192,"journal":{"name":"Topical Meeting on Industrial Applications of Computed Tomography and NMR Imaging","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129686675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many applications of computed tomography either require or would benefit from "real-time" data acquisition and image reconstruction. Real-time is a rather nebulus concept that is specific to each application. However, for visual inspection of the image data, real-time may be equated with video-rate processing. There are many applications where projection data can be collected at this rate. Boyd1 has recently described an x-ray gantry that can collect all the projection data in a time on the order of a video frame time. Real-time reconstruction, on the other hand, is quite difficult and has not been demonstrated on data of any appreciable size. We describe a system for real-time image reconstruction. The system implements the filtered back-projection algorithm and is based on an electro-optic implementation of the filtering operation, an optical back-projection, and integration on a video detector. This system when coupled to a fast data acquisition system will enable on-line real-time inspection of a dynamic process (i.e., "CT video").
{"title":"Reconstruction System for Real-Time CT","authors":"A. Gmitro, G. Gindi","doi":"10.1364/iact.1984.mc3","DOIUrl":"https://doi.org/10.1364/iact.1984.mc3","url":null,"abstract":"Many applications of computed tomography either require or would benefit from \"real-time\" data acquisition and image reconstruction. Real-time is a rather nebulus concept that is specific to each application. However, for visual inspection of the image data, real-time may be equated with video-rate processing. There are many applications where projection data can be collected at this rate. Boyd1 has recently described an x-ray gantry that can collect all the projection data in a time on the order of a video frame time. Real-time reconstruction, on the other hand, is quite difficult and has not been demonstrated on data of any appreciable size. We describe a system for real-time image reconstruction. The system implements the filtered back-projection algorithm and is based on an electro-optic implementation of the filtering operation, an optical back-projection, and integration on a video detector. This system when coupled to a fast data acquisition system will enable on-line real-time inspection of a dynamic process (i.e., \"CT video\").","PeriodicalId":133192,"journal":{"name":"Topical Meeting on Industrial Applications of Computed Tomography and NMR Imaging","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128182504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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