scholarly journals Scatter analysis and correction for ultrafast X-ray tomography

2015 ◽  
Vol 373 (2043) ◽  
pp. 20140396 ◽  
Author(s):  
Michael Wagner ◽  
Frank Barthel ◽  
Johannes Zalucky ◽  
Martina Bieberle ◽  
Uwe Hampel
Keyword(s):  
Phase Distribution ◽  
Imaging System ◽  
Image Data ◽  
Reconstruction Algorithms ◽  
X Ray ◽  
Correction Technique ◽  
Correct Determination ◽  
Ct Radiation ◽  
X Ray Computed ◽  
Radiation Scatter

Ultrafast X-ray computed tomography (CT) is an imaging technique with high potential for the investigation of the hydrodynamics in multiphase flows. For correct determination of the phase distribution of such flows, a high accuracy of the reconstructed image data is essential. In X-ray CT, radiation scatter may cause disturbing artefacts. As the scattering is not considered in standard reconstruction algorithms, additional methods are necessary to correct the detector readings or to prevent the detection of scattered photons. In this paper, we present an analysis of the scattering background for the ultrafast X-ray CT imaging system ROFEX at the Helmholtz-Zentrum Dresden-Rossendorf and propose a correction technique based on collimation and deterministic simulation of first-order scattering.

scholarly journals Optimization of the energy for Breast monochromatic absorption X-ray Computed Tomography

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Pasquale Delogu ◽  
Vittorio Di Trapani ◽  
Luca Brombal ◽  
Giovanni Mettivier ◽  
Angelo Taibi ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Imaging Techniques ◽  
Fixed Dose ◽  
X Rays ◽  
Reconstruction Algorithms ◽  
Contrast Resolution ◽  
X Ray ◽  
X Ray Imaging ◽  
X Ray Computed ◽  
Dose Levels

Abstract The limits of mammography have led to an increasing interest on possible alternatives such as the breast Computed Tomography (bCT). The common goal of all X-ray imaging techniques is to achieve the optimal contrast resolution, measured through the Contrast to Noise Ratio (CNR), while minimizing the radiological risks, quantified by the dose. Both dose and CNR depend on the energy and the intensity of the X-rays employed for the specific imaging technique. Some attempts to determine an optimal energy for bCT have suggested the range 22 keV–34 keV, some others instead suggested the range 50 keV–60 keV depending on the parameters considered in the study. Recent experimental works, based on the use of monochromatic radiation and breast specimens, show that energies around 32 keV give better image quality respect to setups based on higher energies. In this paper we report a systematic study aiming at defining the range of energies that maximizes the CNR at fixed dose in bCT. The study evaluates several compositions and diameters of the breast and includes various reconstruction algorithms as well as different dose levels. The results show that a good compromise between CNR and dose is obtained using energies around 28 keV.

Radiography registration for mosaic tomography

2017 ◽  
Vol 24 (3) ◽  
pp. 686-694 ◽  
Author(s):  
R. F. C. Vescovi ◽  
M. B. Cardoso ◽  
E. X. Miqueles
Keyword(s):  
Computed Tomography ◽  
Phase Correlation ◽  
Field Of View ◽  
Experimental Setup ◽  
Reconstruction Algorithms ◽  
X Ray ◽  
Synchrotron Tomography ◽  
Correlation Image ◽  
X Ray Computed ◽  
Single Dataset

A hybrid method of stitching X-ray computed tomography (CT) datasets is proposed and the feasibility to apply the scheme in a synchrotron tomography beamline with micrometre resolution is shown. The proposed method enables the field of view of the system to be extended while spatial resolution and experimental setup remain unchanged. The approach relies on taking full tomographic datasets at different positions in a mosaic array and registering the frames using Fourier phase correlation and a residue-based correlation. To ensure correlation correctness, the limits for the shifts are determined from the experimental motor position readouts. The masked correlation image is then minimized to obtain the correct shift. The partial datasets are blended in the sinogram space to be compatible with common CT reconstructors. The feasibility to use the algorithm to blend the partial datasets in projection space is also shown, creating a new single dataset, and standard reconstruction algorithms are used to restore high-resolution slices even with a small number of projections.

Visualization of diffusion phenomena in porous media by means of X-ray computed tomography (CT) scanning

2015 ◽  
Vol 52 (10) ◽  
pp. 1448-1456 ◽  
Author(s):  
Akira Sato ◽  
Koichi Ikeda
Keyword(s):  
Computed Tomography ◽  
Porous Materials ◽  
Diffusion Coefficients ◽  
Image Data ◽  
Ct Scanning ◽  
One Dimensional ◽  
X Ray ◽  
Water Permeation ◽  
X Ray Computed ◽  
Stone Structures

The migration of water and contamination materials in rock structures is a significant issue in projects that utilize deep underground locations such as “carbon-dioxide capture and storage” (CCS) and disposal of high-level nuclear waste. These phenomena are also important in the area of preservation of stone structures of cultural heritage signficance, as such stone structures are usually located outside, exposed to wind and rain. The migration of contamination materials in the underground environment, especially in porous rock mass, is governed mainly by water permeation and diffusion. In this study, one-dimensional diffusion testing was conducted and the process in the porous materials was visualized by X-ray computed tomography (CT) scanning. Diffusion is the process caused by the concentrate or density gradient, and is a suitable phenomenon for X-ray CT analysis. In this paper, information related to diffusion is extracted from X-ray CT image data and the distribution of concentration is estimated. From the obtained density distribution, diffusion coefficients are evaluated. One-dimensional permeation tests were also conducted and intrinsic permeabilities of porous materials are evaluated, then the relation between diffusion coefficients and intrinsic permeability is discussed.

scholarly journals Development of Metrological NDE Methods for Microturbine Ceramic Components

2000 ◽  
Author(s):  
H.-R. Lee ◽  
W. A. Ellingson
Keyword(s):  
Data Acquisition ◽  
Vertical Plane ◽  
Coordinate Measuring Machine ◽  
Image Intensifier ◽  
Reconstruction Algorithms ◽  
Volume Data ◽  
X Ray ◽  
Computed Tomographic ◽  
X Ray Computed ◽  
Measuring Machine

In this work, X-ray computed tomographic imaging technology with high spatial resolution has been explored for metrological applications to Si3N4 ceramic turbine wheels. X-ray computed tomography (XCT) data were acquired by a charge-coupled device detector coupled to an image intensifier. Cone-beam XCT reconstruction algorithms were used to allow full-volume data acquisition from the turbine wheels. Special software was developed so that edge detection and complex blade contours could be determined from the XCT data. The feasibility of using the XCT for dimensional analyses was compared with that of a coordinate-measuring machine (CMM). Details of the XCT system, data acquisition, and dimensional comparisons will be presented. Comparison between XCT and CMM dimensions shows that the 3D XCT data have an accuracy of ± 0.2 mm in all three axis whereas the CMM data have an accuracy of ± 0.5 mm in the horizontal plane and ± 0.025 mm in the vertical plane.

scholarly journals XDesign: an open-source software package for designing X-ray imaging phantoms and experiments

2017 ◽  
Vol 24 (2) ◽  
pp. 537-544 ◽  
Author(s):  
Daniel J. Ching ◽  
Dogˇa Gürsoy
Keyword(s):  
Computed Tomography ◽  
Data Acquisition ◽  
Software Package ◽  
Reconstruction Algorithms ◽  
X Ray ◽  
X Ray Imaging ◽  
Imaging Phantoms ◽  
Open Source Software Package ◽  
X Ray Computed ◽  
Image Reconstruction Algorithms

The development of new methods or utilization of current X-ray computed tomography methods is impeded by the substantial amount of expertise required to design an X-ray computed tomography experiment from beginning to end. In an attempt to make material models, data acquisition schemes and reconstruction algorithms more accessible to researchers lacking expertise in some of these areas, a software package is described here which can generate complex simulated phantoms and quantitatively evaluate new or existing data acquisition schemes and image reconstruction algorithms for targeted applications.

Development of novel statistical reconstruction algorithms for poly-energetic X-ray computed tomography

2008 ◽  
Vol 92 (3) ◽  
pp. 289-293 ◽  
Author(s):  
Ho-Shiang Chueh ◽  
Wen-Kai Tsai ◽  
Chih-Chieh Chang ◽  
Shu-Ming Chang ◽  
Kuan-Hao Su ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Reconstruction Algorithms ◽  
X Ray ◽  
Statistical Reconstruction ◽  
X Ray Computed

Ultrafast X-Ray Computed Tomography Imaging for Hydrodynamic Investigations of Gas–Liquid Two-Phase Flow in Centrifugal Pumps

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Thomas Schäfer ◽  
Martin Neumann-Kipping ◽  
André Bieberle ◽  
Martina Bieberle ◽  
Uwe Hampel
Keyword(s):  
Computed Tomography ◽  
Gamma Ray ◽  
Two Phase Flow ◽  
Image Data ◽  
Phase Flow ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Pump Performance ◽  
X Ray ◽  
X Ray Computed

Abstract Gas entrainment into centrifugal pumps decreases pump performance and may raise safety issues, e.g., through insufficient cooling. Although there is some phenomenological knowledge in the form of correlations between operating parameters and pump performance, a further understanding via direct observation of the gas–liquid mixture was so far not possible. In this paper, we demonstrate the capability of ultrafast X-ray computed tomography (UFXCT) to disclose gas–liquid two-phase flow dynamics in the impeller region of a centrifugal pump mockup. Experiments were performed for gas injection at impeller speeds between 1300 rpm and 1600 rpm. We analyzed the X-ray image sequences with respect to characteristics of the gas distribution and compared them with time-averaged image data of a real pump obtained earlier with gamma-ray computed tomography (CT).

A reference sample for investigating the stability of the imaging system of x-ray computed tomography

2016 ◽  
Vol 27 (8) ◽  
pp. 085004 ◽  
Author(s):  
Wenjuan Sun ◽  
Stephen Brown ◽  
Nadia Flay ◽  
Michael McCarthy ◽  
John McBride
Keyword(s):  
Computed Tomography ◽  
Imaging System ◽  
Reference Sample ◽  
X Ray ◽  
X Ray Computed ◽  
The Stability
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