9 Edge Enhancement Computed Tomography (original) (raw)
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Edge Enhancement Computed Tomography
Numerical Analysis - Theory and Application, 2011
In tomography, the probe must be able to cross the sample and carry the information of the structure to the outside. The action exerted upon the object due to the interaction with the medium is known as the projection or profile f and the predominant physical property in
Nature Reviews Methods Primers, 2021
| X-ray computed tomography (CT) can reveal the internal details of objects in three dimensions non-destructively. In this Primer, we outline the basic principles of CT and describe the ways in which a CT scan can be acquired using X-ray tubes and synchrotron sources, including the different possible contrast modes that can be exploited. We explain the process of computationally reconstructing three-dimensional (3D) images from 2D radiographs and how to segment the 3D images for subsequent visualization and quantification. Whereas CT is widely used in medical and heavy industrial contexts at relatively low resolutions, here we focus on the application of higher resolution X-ray CT across science and engineering. We consider the application of X-ray CT to study subjects across the materials, metrology and manufacturing, engineering, food, biological, geological and palaeontological sciences. We examine how CT can be used to follow the structural evolution of materials in three dimensions in real time or in a time-lapse manner, for example to follow materials manufacturing or the in-service behaviour and degradation of manufactured components. Finally, we consider the potential for radiation damage and common sources of imaging artefacts, discuss reproducibility issues and consider future advances and opportunities.
Some sources of artefact in computed tomography
Physics in Medicine and Biology, 1980
A number of sources of error and artefact that may arise in x-ray computed tomography are considered. The importance of temporal and spatial non-uniformities in x-ray tube output and detector sensitivity, of changes in voltage supply, of an incomplete field of view, and of scattered radiation, are analysed by calculating their effect on the reconstructed image, and by estimating the noise power that they introduce. Computer simulation is used whenever the error is dependent on the object. The particular relevance of these errors in CT scanners employing arrays of detectors, such as an image intensifier, is emphasised.
X-ray tomography: the way from layer-by-layer radiography to computed tomography
Computer Optics, 2021
The methods of X-ray computed tomography allow us to study the internal morphological structure of objects in a non-destructive way. The evolution of these methods is similar in many respects to the evolution of photography, where complex optics were replaced by mobile phone cameras, and the computers built into the phone took over the functions of high-quality image generation. X-ray tomography originated as a method of hardware non-invasive imaging of a certain internal cross-section of the human body. Today, thanks to the advanced reconstruction algorithms, a method makes it possible to reconstruct a digital 3D image of an object with a submicron resolution. In this article, we will analyze the tasks that the software part of the tomographic complex has to solve in addition to managing the process of data collection. The issues that are still considered open are also discussed. The relationship between the spatial resolution of the method, sensitivity and the radiation load is re...
Advanced Applications of Computed Tomography by Combination of Different Methods
2006
Advanced applications of materials need sophisticated measurement methods for research, process development and quality control. X-ray Computed Tomography (CT) is a very powerful method for non-destructive testing of materials. A CT-scanner generates a series of X-ray attenuation measurements, which are used to produce computed reconstructed images of an object. In the last years 3D-CT systems with matrix detectors have become
NDT & E International, 2000
An image intensifier based computed tomography scanner and a tube source of X-rays are used for nondestructive evaluation, imaging of small objects for archaeological studies and conservation of works of art and micro analysis of soft materials. It consists of a charge coupled device (CCD) camera and an acquisition board. The CCD camera and the acquisition board allow image processing, filtration and restoration. The object is irradiated by an X-ray tube with a conical collimator and rotated on 180Њ. Projections are obtained at various angles as cross sectional image slices. A reconstruction program written in pascal is able to give the reconstruction matrix of the linear attenuation coefficients, simulates the matrix and related tomography. The flux emitted by the tube is filtered using the appropriate filters at the chosen optimum energy and reasonable monochromacy is achieved for all the images. Although X-ray imaging is a potential tool for strongly attenuating materials, the images of weakly attenuating materials provide new information to know about their structure and also the foreign body for the image reconstruction at an optimum value. The image of the plastic material which contains the internal defect is studied thoroughly at the optimum value in order to image the small objects for nondestructive testing, archaeological studies and conservation of works of art. The images are analysed using the profile data showing the internal defect of the object to obtain information at the optimum value. At the optimum value and with the aid of the tomographic image, the size and location of the defect could be ascertained. ᭧