bluuebunny/crossref_metadata_2025 huggingface dataset:
تصور الأطفال للموت بين الحقيقة والإنكار
Authors: ابو شعبان شيماء , احمد احمد الطيب
Published: April 2023

هدفت الدراسة إلى بيان تصور الأطفال للموت بين الحقيقة والإنكار، اتبع الباحثان المنهج الوصفي التحليلي، والمنهج النوعي، حيث تم اختيار عينة عشوائية قوامها (133) طفل ممن تتراوح أعمارهم ما بين (4-12) عام، طبق عليهم (استبيان تصور الأطفال حول الموت)، (المقابلة الإرشادية الفردية المنظمة)- إعداد الباحثان، وتوصلت الدراسة إلى نتائج عدة مفادها: أن الأطفال في سن (4-6) سنوات ينكرون وجود الموت، بينما يقر الطفل بحقيقة الموت في سن (7-12) عام، ويتطور تصور الطفل للموت تبعاً لمفاهيم متدرجة: (العالمية - المشاعر - النهائية - السببية - توقف الوظائف )، ولا توجد فروق دالة تعزى إلى متغير النوع و العمر وذلك في محور (السببية، توقف أعضاء الجسم، النهائية)، بينما توجد فروق دالة في محوري (العالمية، المشاعر ومستوى التأثر) لصالح الأطفال بالأعمار العليا، ويرى الأطفال عمر (4-6) سنوات الموت أن أسباب الموت ب(عدم المعرفة، سوء الأخلاق - الحروب - المرض- الحوادث)، بينما تصور الأطفال في عمر (7-12) عام، حيث تتحدد لأسباب الموت ترتبط بـ (الأسباب المرضية - القضاء والقدر - الحروب - الحوادث والكوارث).
Uncertainty for uncorrected measurement results in X-ray computed tomography
Authors:   Nikon Metrology, Inc., Villarraga-Gómez Herminso ,   University of North Carolina, Smith Stuart T.
Published: April 2023

In a recent paper [1], a mathematical formalism for the uncertainty estimation of dimensional measurements obtained from X-ray computed tomography (CT) data was outlined. The formalism includes the treatment of both 'corrected'-when the final result is corrected for bias-and 'uncorrected' measurement results. Such formalism is mainly based on the ISO 15530 series and the VDI/VDE 2630-2.1 guidelines. However, the treatment of uncertainty in the 'uncorrected' case-not compensated for bias-is limited to the use of the root-sum-of-squares of standard uncertainties (RSSu) approach. The present paper expands to other possibilities for the uncertainty estimation of 'uncorrected' results that could be applied to CT measurements, namely the root-sum-of-squares of expanded uncertainties (RSSU), the algebraic sum of expanded uncertainty with the signed bias (SUMU), the enlargement of the expanded uncertainty by adding the absolute value of the bias (SUMU MAX), and the so-called U ε method that sums the expanded uncertainty with the absolute value of the bias scaled by a factor assigned for a 95% distribution coverage. In addition, the alternative of using a maximum permissible error (MPE) statement-typically specified by the manufacturer of the CT instrument to get a rough estimate of the expanded uncertainties of CT measurements is considered. Through a concrete example, by using dimensional X-ray CT data extracted from a metallic artifact that has internal features, these possibilities are analysed. From all the possibilities investigated, the RSSu method seems to be the most conservative for the estimation of expanded uncertainties associated with CT dimensional measurement that are not compensated for bias. On the other hand, uncertainty bounds estimated with the MPE-based approach vary little from a constant value, and, therefore, risk creating significant under-or over-estimation of the uncertainty intervals.
Morphological study of defects in laminated joints of composite materials using microCT
Authors:   Federal University of Rio de Janeiro (UFRJ), Guimarães Ferreira Cintia ,   Federal University of Rio de Janeiro (UFRJ), Tadeu Lopes Ricardo ,   Federal University of Rio de Janeiro (UFRJ), Ferreira Oliveira Davi ,   Federal University of Rio de Janeiro (UFRJ), Maria Pires do Santos Thais ,   Federal University of Rio de Janeiro (UFRJ), Oliveira Araújo Olga Maria ,   Petrobras Research Center, Dias Fonseca Martins Fabiana ,   Federal University of Rio de Janeiro (UFRJ), Ribeiro Pereira Gabriela
Published: April 2023

Computed microtomography (microCT) has been used to inspect composite materials of the most varied types. From a volumetric analysis it is possible to characterize the phases (matrix and reinforcement) present in the materials, as well as to determine the percentage of defects that may exist. In laminated joints of pipe in polymeric composite material reinforced by fiberglass, delaminations and voids have been observed that may compromise the strength of these materials. A basic analysis with microCT allows to verify the presence of these occurrences, but to differentiate them a more accurate analysis is necessary. The objective of this study was to analyze computed microtomography of laminated composites. The results quantitative of the matrix and reinforcement were provided and a study of the sphericity of the defects was performed. The results demonstrated that more spherical defects tend to be small voids, whereas less spherical defects correspond to delaminations.
Synchrotron based absorption edge tomography for the analysis of 3D printed polymer embedded MOF
Authors:   BAM Federal Institute for Materials Research and Testing, Gollwitzer Christian ,   BAM Federal Institute for Materials Research and Testing, Scholz Philipp ,   BAM Federal Institute for Materials Research and Testing, Ulbricht Alexander ,   BAM Federal Institute for Materials Research and Testing, Joshi Yogita ,   BAM Federal Institute for Materials Research and Testing, Weidner Steffen
Published: April 2023

Absorption edge tomography (AET), also known as differential tomography at absorption edges, is a method which exploits the

sudden change of the attenuation coefficient, when the photon energy crosses the absorption edge of an element [1]. Synchrotron

radiation is the best source for absorption edge tomography, because of its small bandwidth, high intensity and easily adjustable

photon energy [2]. The synchrotron beamline BAMline at the synchrotron radiation facility BESSY II in Berlin, which is operated

by the Bundesanstalt für Materialforschung und -prüfung (BAM), provides a monochromatized beam in a photon energy range

from 5 keV up to 80 keV with a bandwidth of 2%, when the double multilayer monochromator is used [3]. Together with the

microtomography setup, this enables differential tomography with submicron resolution at the K edge of the elements [4] from

chromium up to the lanthanides, and up to uranium, when the L edges are used as well.

In this work, mechanochemically synthesized metal-organic framework (MOF) material HKUST-1 in combination with acrylonitrile-

butadiene styrene (ABS) polymer was used to form a polymer MOF composite material by a simple extruder. This

composite filament was used for 3D printing. Absorption edge tomography facilitated the evaluation of the 3D distribution of

the MOF material both in the filament and the resultant printed sample up to μm resolution. Our very first data indicate, that

HKUST-1 is mainly homogeneously dispersed in both polymer bulk materials. In addition, a few clusters having significantly

higher Cu concentration were found. AET in combination with data fusion also allows for the calculation of the MOF amount

located on the external polymer surface.
Thicknes Measurement of Metal Plate Using CT Projection Images and Nominal Shape
Authors:   University of Tokyo, Ito Tasuku ,   University of Tokyo, Ohtake Yutaka ,   Tokyo Metropolitan University, Nagai Yukie ,   University of Tokyo, Suzuki Hiromasa
Published: April 2023

X-ray computed tomography (CT) is important in industrial process control because it allows non-destructive inspection of a wide
range of components. CT scanning requires thousands of projection images to be captured, however, which makes this inspection
very time-consuming process. This study establishes a new method for measuring the thickness of parts with shortened scanning
and computation times by using only 10 to 30 projection images and predefined nominal shape of the part. The nominal shape is
aligned with each projection of the part’s image, and the dimensions of the part are then computed on the basis of the projection
images and the nominal shape. In preliminary tests, the approach proved effectiveness for measuring the thickness of a metal
bracket and a metal plate.
Validation of a Method for the Optimization of Scan Parameters for Measuring with Computed Tomogography
Authors:   Dresden University of Technology (TU Dresden), Christoph Raoul ,   Werth Messtechnik GmbH, Leinweber Carsten ,   Werth Messtechnik GmbH, Fischer Alexander ,   Dresden University of Technology (TU Dresden), Weise Hartmut ,   German Center for Cancer Research (DKFZ), Kachelrieß Marc
Published: April 2023

When measuring with computed tomography, the measurement uncertainty of measured values is strongly influenced by the geometry and material of the measured object as well as by the chosen scan parameters, such as those of the X-ray source and detector. Optimizing the scan parameters to achieve a sufficiently high measurement precision while keeping the measurement time as short as possible, is crucial for the efficient use of a coordinate measuring machine. Few tools are available to aid the user at the moment. Therefore scan parameters are often set based on purely empirical studies or subjective assessments of X-ray images and thus on the basis of personal experience. A new method for the automatic determination of scan parameters for a given measurement time or a given measurement precision of a single measurement point, as well as a given minimum necessary structural resolution has been developed. It is based on a method for simulating the measurement precision of surface points that are relevant for the measurement task. In this work, values for scan parameters to maintain the highest possible single point precision for a given measurement time and minimum necessary structural resolution have been determined for a multi-sphere standard using the newly developed setting algorithm and by evaluating empirical studies. The results of both methods are presented and compared.
Utilization of single point uncertainties for geometry element regression analysis in dimensional X-ray computed tomography
Authors:   University of Erlangen-Nürnberg (FAU), Müller Andreas Michael ,   University of Erlangen-Nürnberg (FAU), Hausotte Tino
Published: April 2023

The work outlined in this paper is examining ways to incorporate previously determined single point uncertainties of computed
tomography (CT) measurements into a suitable regression analysis in order to evaluate standard geometry elements. The goal is
to determine and reduce the measurement uncertainty for the specific parameters of a geometry element by using selective point
rejections based on their single point uncertainty. Examinations show that the systematic error as well as the associated
uncertainties can be reduced in certain scenarios compared to the statistical interpretations of repeated (simulated) measurements
without considering the single point uncertainty. Nonetheless, these results still need to be verified for different data series and
measurement setups.
A Novel Approach for Immediate, Interactive CT Data Visualization and Evaluation using GPU-based Segmentation and Visual Analysis
Authors:   VRVis Research Center for Virtual Reality and Visualization Ltd, Steinlechner H. ,   VRVis Research Center for Virtual Reality and Visualization Ltd, Haaser G. ,   Austrian Foundry Research Institute, Oberdorfer Bernd ,   Austrian Foundry Research Institute, Habe Daniel ,   VRVis Research Center for Virtual Reality and Visualization Ltd, Maierhofer S. ,   VRVis Research Center for Virtual Reality and Visualization Ltd, Schwärzler M. ,   Vienna University of Technolog (TU), Gröller Eduard
Published: April 2023

CT data of industrially produced cast metal parts are often afflicted with artefacts due to complex geometries ill-suited for the
scanning process. Simple global threshold-based porosity detection algorithms usually fail to deliver meaningful results. Other
adaptive methods can handle image artefacts, but require long preprocessing times. This makes an efficient analysis workflow
infeasible. We propose an alternative approach for analyzing and visualizing volume defects in a fully interactive manner, where
analyzing volumes becomes more of an interactive exploration instead of time-consuming parameter guessing interrupted by
long processing times. Our system is based on a highly efficient GPU implementation of a segmentation algorithm for porosity
detection. The runtime is on the order of seconds for a full volume and parametrization is kept simple due to a single threshold
parameter. A fully interactive user interface comprised of multiple linked views allows to quickly identify defects of interest,
while filtering out artefacts even in noisy areas.
An Interactive Visual Comparison Tool for 3D Volume Datasets represented by Nonlinearly Scaled 1D Line Plots through Space-filling Curves
Authors:   Upper Austrian University of Applied Sciences (FH OÖ), Weissenböck Johannes ,   Upper Austrian University of Applied Sciences (FH OÖ), Fröhler Bernhard ,   Vienna University of Technolog (TU), Gröller Eduard ,   University of Antwerpen, Sanctorum Jonathan ,   University of Antwerpen, De Beenhouwer Jan ,   University of Antwerpen, Sijbers Jan ,   Fischer Advanced Composite Components (FACC), Ayalur Karunakaran Santhosh ,   Fischer Advanced Composite Components (FACC), Hoeller Helmuth ,   Upper Austrian University of Applied Sciences (FH OÖ), Kastner Johann ,   Upper Austrian University of Applied Sciences (FH OÖ), Heinzl Christoph
Published: April 2023

The comparison of many 3D volumes to find subtle differences is tedious, time-consuming and error-prone. Previously we presented Dynamic Volume Lines [1], a novel tool for the interactive visual analysis and comparison of ensembles of 3D volumes, which are linearized using Hilbert spacing-filling curve and represented as 1D line plots. In this paper we further demonstrate the usefulness and capabilities of our method by conducting a detailed visual analysis and evaluation of an artificial specimen from simulated 3D X-Ray Computed Tomography (XCT) and a real-world XCT titanium alloy specimen.
Simulated grating-based x-ray phase contrast images of CFRP-like objects
Authors:   University of Antwerpen, Sanctorum Jonathan ,   University of Antwerpen, De Beenhouwer Jan ,   Upper Austrian University of Applied Sciences (FH OÖ), Weissenböck Johannes ,   Upper Austrian University of Applied Sciences (FH OÖ), Heinzl Christoph ,   Upper Austrian University of Applied Sciences (FH OÖ), Kastner Johann ,   University of Antwerpen, Sijbers Jan
Published: April 2023

Because of their microstructure, carbon fibre reinforced polymers outperform conventional materials in many aspects. These

materials are, given the low x-ray absorption contrast they provide, ideally suited for phase contrast x-ray computed tomography.

For system prototyping and for benchmarking and testing acquisition and reconstruction procedures, computer simulations are a

valuable tool. In this paper, we propose the application of an alternative simulation strategy that unites Monte Carlo simulations

with numerical wave optics and involves detailed modelling of the internal carbon fibre reinforced polymer structure down to the

individual fibre scale.
CT machine geometry changes under thermal load
Authors:   Federal Institute of Metrology METAS, Bircher Benjamin A. ,   Federal Institute of Metrology METAS, Meli Felix ,   Federal Institute of Metrology METAS, Küng Alain ,   Federal Institute of Metrology METAS, Thalmann Rudolf
Published: April 2023

Computed tomography systems are increasingly used for dimensional metrology. Accurate CT machine geometry and
temperatures close to 20 °C are crucial for dimensional measurements. Usually, considerable thermal loads are imposed onto CT
systems by the X-ray source and the detector that dissipate heat in the order of 100 W. Because temperature variations and
gradients induce deformations on the machine geometry, it is crucial to characterise and control such influences. Here, a homebuilt
water cooling system for a flat-panel X-ray detector was characterised for heat dissipation into the CT system, positional
and angular drift, and pixel grey value stability.
X-ray microtomography study of pellet/powder bentonite mixture upon wetting
Authors:   Ecole des Ponts ParisTech, Molinero Guerra Agustín ,   Ecole des Ponts ParisTech, Aimedieu Patrick ,   Ecole des Ponts ParisTech, Bornert Michel ,   Ecole des Ponts ParisTech, Cui Yu-Jun ,   Ecole des Ponts ParisTech, Tang Anh Minh ,   Tongji University, Sun Zhao ,   Institut de Radioprotection et de Sureté Nucléaire (IRSN), Mokni Nadia ,   Ecole des Ponts ParisTech, Delage Pierre ,   Agence Fédérale de Contrôle Nucléaire (AFCN), Bernier Frédéric
Published: April 2023

Among the techniques considered to seal radioactive waste in geological layers, pellet/powder bentonite mixture appears to be

an interesting candidate due to its swelling properties and high radionuclide migration retardation properties. One of the key

issues related to this material is its change in microstructure upon wetting. A special experiment was performed, aiming at

evaluating such microstructure changes. A cylindrical column, filled with initially heterogeneous mixture, was submitted to

wetting during several monthes. X-ray microtomography was used to follow the temporal three-dimensional evolution of the

mixture. The pores between the pellets were found to be progressivelly filled, allowing a quasi-homogeneous material to be

reached at the end.
3-in-1 X-ray Computed Tomography
Authors:   The Manufacturing Technology Centre (MTC), Turner Nathanael ,   The Manufacturing Technology Centre (MTC), Brierley Nicholas ,   University of Huddersfield, Townsend Andrew
Published: April 2023

For over 30 years, X-ray Computed Tomography (CT) has been used for Non-Destructive Testing (NDT) of manufactured components
for validation of internal integrity [1]. More recently the first X-ray CT systems dedicated to dimensional metrology
applications have reached the market. Since then, the field of dimensional X-ray CT has gained much interest, especially for
inspection of Additively Manufactured (AM) components [2]. This novel manufacturing route has brought new challenges for
inspection due to internal or inaccessible features and unique surface characteristics. Recent research has demonstrated the feasibility
for surface metrology with commercially available micro-CT systems [3] [4]. The potential for performing dimensional,
integrity and surface analysis within a single process has made X-ray CT highly desirable for AM inspection. Further innovation
is required however, in order to produce a commercial hardware and software that can complete the complex workflow required
for 3-in-1 inspection.
Tomographic investigation of the gothic sculpture
Authors:   Czech Academy of Sciences (CAS), Vavrik Daniel ,   National Gallery, Chlumská Štepánka ,   Czech Academy of Sciences (CAS), Kumpova Ivana ,   National Gallery, ševců Radka ,   Czech Academy of Sciences (CAS), Vopalensky Michal ,   Czech Technical University (CVUT), Zemlicka Jan
Published: April 2023

Aim of the work is non-destructive investigation of the gothic sculpture Dolorosa from the The Collection of Old Masters of the National Gallery in Prague. This sculpture is decorated using so-called polychromy, which consists of layers in a variety of colors. It is also common that such artifacts have been renovated several times. Therefore, it is highly desirable to investigate the material composition of the existing polychromy. Obviously, information about possible reparations and hidden inner defects is required as well. It is relatively easy to explore the internal structure of wooden sculptures by utilizing X-ray computed tomography.
Comparison of different voxel size calibration strategies
Authors:   University of Zagreb, Katic Marko ,   University of Zagreb, Barsic Gorana
Published: April 2023

Coordinate measuring machines (CMM) are traditionally used in industry for verifying geometric dimensions and tolerances of parts. In the last decade X-ray computed tomography (CT) is being increasingly used in industry for dimensional analysis purposes as well. Tactile CMM is based on point-to-point collection of measurement data, while CT scans entire workpiece and generates a volumetric point cloud of measurement data. The influence of different approaches in gathering of data when using CMM and CT on calculation of voxel size is experimentally tested and discussed in this work and compared with other standard voxel size calibration options like use of reference standards and calibration of magnification axis. Several typical industrial workpieces are used to demonstrate the differences that arise because of different voxel size calibration strategies.
Voxel size and calibration for CT measurements with a small field of view
Authors:   Brno University of Technology (BUT), Blažek Pavel ,   Czech Metrology Institute (CMI), Šrámek Jan ,   Brno University of Technology (BUT), Zikmund Tomáš ,   Brno University of Technology (BUT), Kalasová Dominika ,   Czech Metrology Institute (CMI), Hortvík Václav ,   Brno University of Technology (BUT), Klapetek Petr ,   Brno University of Technology (BUT), Kaiser Jozef
Published: April 2023

Dimensional tomographic measurement is influenced by many factors. To achieve metrological traceability of results, knowledge of influence factors and their effect on measurement is important. This includes knowledge of the true value of voxel size and edge detection. Phantoms used for characterization and correction of error sources are calibrated usually on tactile or optical coordinate measuring machines. The challenge here is the manufacturing and calibration of small phantoms, which can be used in the field of view approximately 1 mm and less, which is the case of tomographic devices aiming at high resolution. In this work, abilities of a nano-coordinate measuring machine (nano-CMM) SIOS NMM-1 (Nanopositioning and Nanomeasuring Machine) to calibration of a phantom for X-ray computed tomography (CT) with the small field of view and high resolution are tested.
A Curvelet based Sinogram Correction Method for Metal Artifact Reduction
Authors:   National Institute for Mathematical Sciences, Jeon Kiwan ,   National Institute for Mathematical Sciences, Park Hyoung Suk
Published: April 2023

In the X-ray computed tomography (CT) imaging, metal artifact occurs often due to the non linear attenuation effect of the
metallic subject with respect to the photon energy. Especially high attenuated material, such as plumbum (Pb.) can easily
distort the sinogram due to the few remaining of the information on the metal traces. The remedy of such a circumstance,
an image inpainting algorithm is useful to fill the missing information in the sinogram. Most metal artifact reduction (MAR)
algorithm based on inpainting consist of the filling the missing values using only informations around the matal traces. Without
the consideration of the continuity of the sinogram, the inpainting method can generate addition artifact as a side effect. In this
paper, we propose a curvelet based inpainting method to promote the continuity of the sinogram, induced by the rotation of the
X-ray scan system. Numerical simulation and phantom experiment are provided to support the our assertion.
Helical XCT measurement for correlative imaging
Authors:   Brno University of Technology (BUT), Břínek Adam ,   Brno University of Technology (BUT), Lázňovský Jakub ,   Brno University of Technology (BUT), Zikmund Tomáš ,   Brno University of Technology (BUT), Salplachta Jakub ,   Brno University of Technology (BUT), Kaiser Jozef
Published: April 2023

The X-ray computed tomography (XCT) is more often used to scan long objects that exceed the dimensions of the detector. Conventional scans/systems using circular trajectories touches the limits when dealing whit elongated samples. Helical scanning is a valuable solution in such a case. It enables to shorten scanning time, getting strong improvement on image quality, eliminating the cone beam artifacts and beam hardening. These benefits make from the helical trajectory strong tool for correlative approaches with other imaging techniques. In this work, images obtained by helical trajectory are investigated and compared with those acquired by conventional circular scans. Experimental results show that helical scanning with appropriate scan parameters performs better quality than traditional circular scans with an improvement in image quality.
Scatter Correction for Industrial Cone-Beam Computed Tomography (CBCT) Using VSHARP, a fast GPU-Based Linear Boltzmann Transport Equation Solver
Authors:   Varex Imaging Corporation, Shiroma Amy ,   Varex Imaging Corporation, Star-lack Josh ,   Varex Imaging Corporation, Holt Kevin ,   Varex Imaging Corporation, Hu Martin ,   Varex Imaging Corporation, Hoelzer Steve ,   Varex Imaging Corporation, YOON Sungwon ,   Varex Imaging Corporation, Sosnovsky Eugeny ,   Varex Imaging Corporation, Failla Gregory ,   Varian Medical Systems, WANG Adam ,   Varian Medical Systems, Kokkonen Petri ,   Varian Medical Systems, Ruprech Martin ,   Varian Medical Systems, Maslowski Alexander ,   Varex Imaging Corporation, Nisius David
Published: April 2023

The use of cone-beam computed tomography (CBCT) to inspect objects containing aluminum, Inconel and other metals is a challenge due to high amounts of scattered radiation in the projection data. Following in the footsteps of VSHARP, our kernel-based two-dimensional (2D) software scatter correction algorithm that operates on x-ray projection data, we introduce three-dimensional (3D) VSHARP designed to offer improved accuracy and flexibility. The core of 3D VSHARP is fast finite element Linear Boltzmann Transport Equation (LBTE) solver that models photon transport within the object-of-interest and computes the scatter component of the projection data with Monte Carlo-like accuracy but greatly reduced computation times. 3D VSHARP utilizes an object model consisting of 3D material density maps based on a first pass reconstruction, and an imaging chain model describing the system geometry, the x-ray source components (polychromatic spectrum, beam filtration, and collimation hardware), and the x-ray detector components (flat-panel imager in this case). The 3D material density maps making up the object model may be further informed by Computer Aided Design (CAD) files. Validation against Monte Carlo (MC) simulations of overlapping metal blocks showed that 3D VSHARP- and MC-computed scatter fractions agreed to within 3% RMS. The 3D VSHARP execution time was less than 1 sec per projection using a single NVidia TitanXp GPU (NVidia Inc., Santa Clara CA) while the MC simulations took 1566 CPU-hours using two Intel-Silver-Xenon, 2.2 GHz, 10x core CPU (Intel Inc., Santa Clara CA), in a Dell 7920 workstation (Dell Inc., Austin TX). Experimental CBCT scans were taken of an aluminum motorcycle cylinder head and Inconel turbine blade at 450kVp. Results showed that high quality reconstructions and volume renderings were obtained which may open up the possibility of in-line CBCT applications.
Software-based compensation of computed tomography instrument misalignments – experimental study
Authors:   Catholic University of Leuven (KU Leuven), Ametova Evelina ,   Catholic University of Leuven (KU Leuven), Ferrucci Massimiliano ,   Catholic University of Leuven (KU Leuven), Dewulf Wim
Published: April 2023

A newly developed software-based compensation of geometrical misalignments is applied to several computed tomography (CT) instruments. The actual geometry of each CT instrument is measured using a dedicated procedure. Then, given the measured geometries, software-based compensation is applied. Dimensional measurements on a validation object show a consistent reduction in observed errors as a result of the compensation. Robustness of the compensation method is confirmed also on a CT instrument with severe misalignments.
Influencing factors in x-ray spectral estimation of industrial CT using transmission
measurements
Authors:   Catholic University of Leuven (KU Leuven), Cao Wenchao ,   Catholic University of Leuven (KU Leuven), Pauwels Ruben ,   Nikon Metrology UK Ltd, Fardell Gemma ,   Nikon Metrology UK Ltd, Price Ben ,   Catholic University of Leuven (KU Leuven), Dewulf Wim
Published: April 2023

The X-ray spectrum provides important information for many industrial CT tasks. Transmission measurement based methods
have long been employed in X-ray spectral estimation. There are two advantages of this method. First, no photon counting
detector is needed. Second, the detector response is included in the estimation. However, these methods are subject to influencing
factors of various sources. This work uses simulation to obtain a thorough insight into these potential influencing factors. The
influencing factors are simulated separately and the corresponding impact on the spectral estimation are quantified and compared.
This work is intended to serve as a guide for the experimental design of the real world spectral estimation. By quantifying the
impact of the potential influencing factors, we can subsequently prioritize them and decide which ones need further action.
Initial result on the use of tetrahedra-based imaging for limited angle tomography
Authors:   University of Southampton, Biguri Ander ,   University of Southampton, Towsyfyan Hossein ,   University of Southampton, Boardman Richard ,   University of Southampton, Blumensath Thomas
Published: April 2023

Using tetrahedra as image basis in tomography has potentially beneficial consequences for industrial CT, especially when the

shape of the piece to be scanned is known a priory. This work explores how voxel-based and tetrahedra-based images compare in

the limited angle CT case, using iterative algorithms with and without boundary masking. The study shows that the tetrahedrabased

image reconstruction can discriminate surface features with more detail than the voxel-based image.
Back-projection Filtration Image Reconstruction Approach for Reducing Out-of-plane Artifacts in Laminography
Authors:   Korea Advanced Institute of Science and Technology (KAIST), So Jeongtae ,   Korea Advanced Institute of Science and Technology (KAIST), Kim Hyeongseok ,   Korea Advanced Institute of Science and Technology (KAIST), Lee Donghyeon ,   Korea Advanced Institute of Science and Technology (KAIST), Pua Rizza ,   Korea Advanced Institute of Science and Technology (KAIST), Cho Seungryong
Published: April 2023

Because of incomplete depth information in computed laminography, 3D reconstructed images are contaminated by out-of-plane artifacts, or ripple artifacts along the depth direction. Furthermore, these issues become more severe whenever printed circuit boards (PCB) are imaged due to the presence of high density materials, such as ball grid array, chips, etc. In this reasearch, in order to remove these artifacts, we proposed the use of the voting strategy. This method is a weighted back-projection which gives less weight to outliers, or odd values. However, standard analytical reconstruction methods, such as filtered back-projection (FBP), cannot fully judge and remove the outliers. Thus, we proposed to combine this strategy with the back-projection filtration (BPF) reconstruction method, which first reconstructs the derivative of the projection image, and then filters the reconstructed image by the Hilbert transform. Ripple artifacts were shown to have been dramatically reduced by using the voting strategy in the BPF algorithm.
Investigating the influence of workpiece placement on the uncertainty of measurements in industrial computed tomography
Authors:   RWTH Aachen University, Schmitt Robert H. ,   RWTH Aachen University, Buratti Andrea ,   RWTH Aachen University, Grozmani Natalia
Published: April 2023

Industrial X-ray computed tomography (CT) is a powerful technique for producing a three-dimensional model of an object and

for performing dimensional measurements of an object’s inner and outer features. The diversity of the measuring objects causes

a variety of CT setup parameters. The chosen CT setup parameters influence the uncertainty of dimensional measurements. A

CT user determines the workpiece orientation and the distance between the workpiece and the X-ray source before a CT scan is

commenced, and all other CT setup parameters are based on the workpiece placement inside the CT system. Hence, the workpiece

placement is the trend-setting parameter of a CT scan.

This paper presents a method for optimising a workpiece placement for dimensional measurements of multi-material workpieces.

The method works with the stereolithography (STL) model of the workpiece and analytically tests the whole placement range to

find the placement that minimises the attenuation power of a workpiece. The method is validated by analysing the standard deviation

of CT measurements on a multi-material workpiece. An analysis of variance on the uncertainty contributions demonstrated

that the predicted workpiece placement was optimal.
Development of Reference Samples to Study the Effects of Systematic Errors of Industrial X-ray Computed Tomography
Authors:   National Physical Laboratory (NPL), SUN Wenjuan ,   National Physical Laboratory (NPL), Brown Stephen
Published: April 2023

X-ray computed tomography (XCT) has been increasingly used for dimensional metrology. However, the impact of systematic errors has not been well studied. Typical systematic errors of XCT includes scattering, beam hardening, cone beam errors etc. The impact of these systematic errors on dimensional metrology is an on-going research topic. At the United Kingdom’s National Physical Laboratory a set of reference samples have been developed to study the impact of these systematic effects, especially when measuring metal components. The samples developed include the stair case reference sample, the additive manufacturing (AM) reference sample and the large industry reference sample. The paper discusses the establishment of reference data for XCT using traceable measurement instruments and the applications of these samples in investigating the impact of systematic effects.
Study of keyhole-porosities in selective laser melting using X-ray computed tomography
Authors:   Catholic University of Leuven (KU Leuven), Thanki Aditi ,   Catholic University of Leuven (KU Leuven), Goossens Louca ,   Catholic University of Leuven (KU Leuven), Mertens Raya ,   Catholic University of Leuven (KU Leuven), Probst Gabriel Maurício ,   Catholic University of Leuven (KU Leuven), Dewulf Wim ,   Catholic University of Leuven (KU Leuven), Witvrouw Ann ,   Catholic University of Leuven (KU Leuven), Yang Shoufeng
Published: April 2023

The occurrence of keyhole porosity in selective laser melting (SLM) has so far not been quantified systematically using X-ray computed tomography (X-CT). In this study, keyhole porosity in selective laser molten Ti-6Al-4V grade 23 parts was analyzed using post-process characterizations. Single tracks were produced with optimum, high volumetric energy density and low volumetric energy density parameters on the top of SLM substrate. High volumetric energy density was achieved by either (i) high laser power and optimum scan speed to study the effect of laser power or (ii) optimum laser power and low scan speed to study the effect of scan speed. Keyhole porosity is sensitive to the SLM process parameters. It was observed by using X-CT that a high amount of keyhole porosity was formed below the line scan produced with a high volumetric energy density achieved by optimum laser power and low scan speed; however, a line scan produced with same volumetric energy density but achieved by high laser power and optimum scan speed resulted in less or no voids. The X-CT porosity analysis helped to understand the size, shape, location, and number of keyhole pores that were formed.
Comparison of Geometrically Derived Quality Criteria regarding Optimal Workpiece Orientation for Computed Tomography Measurements
Authors:   University of Erlangen-Nürnberg (FAU), Butzhammer Lorenz ,   University of Erlangen-Nürnberg (FAU), Müller Andreas Michael ,   University of Erlangen-Nürnberg (FAU), Hausotte Tino
Published: April 2023

In the field of industrial Computed Tomography (CT), the orientation of the workpiece influences the local quality of the reconstructed volume data and therefore dimensional measurements. In the literature, different a priori criteria for an optimal orientation are proposed, which are purely based on the part and setup geometry. However, it is not evident to which extent they correlate with the measurement accuracy or how different quality parameters should be weighted, especially if a wider range of materials and therefore different artefact contributions should be covered. In this work, existing methods and criteria are compared and extended. In contrast to most existing investigations, different quality parameters are evaluated not only globally, but also restricted to relevant regions of interest (ROI). A straightforward derivation for an analytical determination of surface areas affected by cone-beam artefacts is presented. Results show that an ROI-based evaluation is important to find an optimal orientation for single measurands. The investigated quality parameter based on the prediction of surface areas which are affected by cone-beam artefacts was found to be applicable as exclusion criterion. This only holds true if the evaluation is restricted to relevant ROI surface areas, which should also be considered when evaluating the maximum X-ray penetration length as quality parameter. The correlation of the latter with resulting measurement deviations was found to depend on the measurement task.
X-ray source tracking to compensate focal spot drifts for dimensional CT measurements
Authors:   Federal Institute of Metrology METAS, Bircher Benjamin A. ,   Federal Institute of Metrology METAS, Meli Felix ,   Federal Institute of Metrology METAS, Küng Alain ,   Federal Institute of Metrology METAS, Thalmann Rudolf
Published: April 2023

Accurate CT measurements rely on a stable X-ray focal spot. Because focal spot drift deteriorates CT data, especially at high resolutions, drift compensation is crucial. Here, we present an optical X-ray tube tracking system that does not require fiducial markers and/or radiographic image registration. To assess its performance, a calibrated, small volume (< 4 mm) multi-sphere standard was CT scanned. The deviations of unidirectional dimensional measurements were reduced by almost a factor of two when compensating for the X-ray tube drift.
CT performance of compact X-ray source with small focal spot using a 950 keV linear accelerator
Authors:   Nikon Corporation, Matsunaga Norihito ,   Nikon Corporation, Sato Tomoya ,   Nikon Corporation, Yamada Atsushi ,   Nikon Corporation, Zaike Masayuki ,   Nikon Corporation, Nikai Daisuke ,   Accuthera Inc., Hatano Tadashi ,   Accuthera Inc., Yamamoto Masashi
Published: April 2023

A 950 keV X-ray source with small focal spot using a linear accelerator has been developed. By installing a focusing mechanism of electron beam, smaller focal spot (0.3 mm in FWHM of the line spread function) is successfully achieved at 950 keV. 9.3 GHz (X-band) radio frequency is used for accelerating electrons in order to make the size of X-ray source smaller, compared to lower radio frequency such as 3.0 GHz (S-band). Size and weight of the developed X-ray source are W 600 mm × D 800 mm × H 500 mm and 230 kg, respectively. Clearer transmission images using a rectangular groove sample are obtained with small spot setup, compared to conventional one. CT images are also obtained for an engine block, and we demonstrated that advantage of 950 keV X-ray source for CT imaging such as improvement of interior visibility and decrease of artefact, compared to a 450 kV X-ray source. Therefore, we are convinced that this 950 keV X-ray source is widely useful for industrial non-destructive inspection of large structures, because of compactness, high transmission ability and spatial resolution.
Correlative Tomography – Combining x-ray nanotomography and FIB/SEM serial sectioning to analyze Al-Si cast alloys
Authors:   Saarland University, Engstler Michael ,   Saarland University, Fell Jonas ,   Fraunhofer-Institute for Non-Destructive Testing (IZFP), Maisl Michael ,   Fraunhofer-Institute for Non-Destructive Testing (IZFP), Herrmann Hans-Georg ,   Saarland University, Mücklich Frank
Published: April 2023

Aluminium alloys with silicon as their major alloying element are widely used in die or sand casting of machine or vehicle parts. The microstructure of hypereutectic Al-Si alloys (>12% Si) consist of primary silicon particles and the Al-Si eutectic. Elements such as Cu, Mg and Ni are added in order to form a great variety of different intermetallic phases which improve mechanical properties at elevated temperatures. Size, shape and connectivity of these complexly formed intermetallic phases play a decisive role for the properties and are for that reason of great interest. As the complex shapes and connectivity are not accessible by means of classical 2D techniques, 3D analysis of the microstructure is mandatory. Due to the size of the particles in the ?mrange, only high resolution 3D imaging techniques are suitable. In this work we used 3D X-ray Microscopy as well as FIB/SEM Serial Sectioning to image the microstructure of an AlSi12Cu4Ni2Mg cast alloy. 3D images were taken at the very same sample volume in order to compare information gained from the different techniques.
Phantom development applied to industrial tomography in composite material pipeline
Authors:   Petrobras Research Center, Dias da Silva Weslley Carlos ,   Federal University of Rio de Janeiro (UFRJ), Lopes Ricardo Tadeu ,   Federal University of Uberlândia (UFU), Viana Duarte Marcus Antônio
Published: April 2023

Computed tomography allows the images reconstruction and the internal details visualization of the internal structure of the inspected volume, which generates a competitive gain for this technique in relation to the other NDT (Non-Destructive Testing) methods. Within this context, Petrobras has an R&D project in partnership with UFRJ (Federal University of Rio de Janeiro) to develop a field microCT for pipeline inspection with adhesive and laminated joints made of composite material. This work developed phantoms in polymeric material for study some parameters, such as contrast resolution, spatial resolution and dimensional metrology. Four phantoms were projected and manufatured for theses purposal. The objective was to study, measure and qualify parameters for the field microCT. The development and evaluation of these phantoms are presented throughout this work. It was possible to observe a good difference between the materials inserted in the contrast resolution phantom through the grey values measurement. Beyond it, it was achieved a spatial resolution about 200 ?m for this phantom, which is a reasonable value for microCT applied to pipelines inspection. Finally, the statistical analyses shown a good data quality and were very usefull to understand the results, which provide a good traceability for them.
Scan quality optimization for measuring Fiber-Metal-Laminates with X-Ray computed tomography
Authors:   University of Augsburg, Thum Florian ,   University of Augsburg, Zott Mario ,   University of Augsburg, Sause Markus G.R.
Published: April 2023

In this study, X-Ray computed tomography is used as an inspection method for Fiber-Metal-Laminates (FML) with an aluminum core and a carbon fiber reinforced thermoplastic matrix. As the mechanical characteristics of thermoplastic based FML strongly depend on the quality of the interface between metal and laminate, it is important to particularly investigate this region. However, the aluminum core may cause beam-hardening artifacts, which reduce the image quality especially in high-resolution scans. Therefore, a parameter study was carried out using different combinations of metal filters out of aluminum and copper to find an efficient balance between artifact reduction and scan duration. The investigated FML-specimens are used for short-beam shear tests (SBS). The optimized parameters lead to a scan quality, which allows for a more detailed description of both matrix cracking and delamination at the interface between the aluminum core and the fiber-reinforced-polymers (FRPs). As a reference measurement of the FML specimens, we used a computed tomography scan acquired at the Synchrotron radiation facility SOLEIL.
3D spatial resolution evaluation for helical CT according to ASTM E1695 – 95
Authors:   Brno University of Technology (BUT), Lázňovský Jakub ,   Brno University of Technology (BUT), Břínek Adam ,   Brno University of Technology (BUT), Zikmund Tomáš ,   Thermo Fisher Scientific, Young Ben ,   Thermo Fisher Scientific, Patáková Zuzana ,   Brno University of Technology (BUT), Kaiser Jozef
Published: April 2023

We propose a new segmentation method for separating parts of a mechanical assembly in a CT volumetric image. Part segmentation is generally based on edge detection with gradient norms of the CT volumetric image, which often fails when parts made of the same material come into close contact. This is because an image is blurry between the parts with low gradient norms and indistinct edges. In order to enhance weak edges at such faded part boundaries, our idea is to enhance the gradient norm in a CT volumetric image. To find such faded boundaries, auxiliary information needs to be introduced. In this paper, two practical cases of the faded boundaries in plastic and welded assemblies of sheet metal parts are studied. For the former case, CAD mesh models of target parts are used. The faded boundaries are found in blurred regions on the CAD mesh boundaries. For the latter case, the thickness value of the sheet metal parts used, and it is assumed to be constant. The faded boundary can be located at the distance of the thickness from the outer surface of the part. By enhancing the gradient norms in those faded boundaries, the assembly of parts made of the same material can be segmented. The algorithms are implemented, and experimental results are demonstrated.
Improving geometry element regression analysis for dimensional X-ray computed tomography measurements using locally determined quality values
Authors:   University of Erlangen-Nürnberg (FAU), Müller Andreas Michael ,   University of Erlangen-Nürnberg (FAU), Hausotte Tino
Published: April 2023

X-ray computed tomography (CT) enables the determination of numerous dimensional measurands with a single scan. However, measurements are often affected by artefacts, which are mainly caused by the effects of the complex physical interactions between the used radiation, the measurement object and the detector as well as the algorithms used for measurement data processing. Surface regions affected by artefacts lead to an inaccurate surface determination and therefore to increased measurement deviations and uncertainties of geometric measurements. This contribution aims to demonstrate the possibility of detecting negatively affected surface regions by a qualitative examination of the underlying volume data in the region of each determined surface point. This classification is used to improve different kinds of sphere measurements, which are evaluated by performing regression analysis onto the measured point clouds. Because of the available qualitative classification for each surface point, it is possible to apply a suitable weighting metric before applying the regression analysis in order to reduce the influence of lowly classified surface areas onto the measurement result. The workflow is demonstrated with a calibrated multi-sphere specimen. The results show that a significant reduction of the measurement errors associated with the evaluation of sphere centre distances, sphere form and radius deviations, respectively, can be achieved, while using the regression analysis tools of the commercial software VGStudio Max (Volume Graphics GmbH).