bluuebunny/crossref_metadata_2025 huggingface dataset:
L0 Regularized Image Deblurring applied to Porosity Analysis in Industrial X-ray Computed Tomography
Authors:   Catholic University of Leuven (KU Leuven), Wu Dong ,   Catholic University of Leuven (KU Leuven), Guerrero Patricio ,   Catholic University of Leuven (KU Leuven), Sinico Mirko ,   Catholic University of Leuven (KU Leuven), Dewulf Wim
Published: February 2023

X-ray Computed Tomography (xCT) is a very effective way of detecting and characterizing the internal information of objects. However, blur is frequent in high-energy industrial xCT (ixCT), degrading image quality and spatial resolution. Therefore, this paper explores the application of L0 regularization to image deblurring in ixCT. With sparsity information of both intensity image and gradient image, the blur is alleviated and both image quality and porosity identification are improved. The method is validated through real ixCT experiments of an additively manufactured component.
Flexible Generation of Prior Images for Metal Artifact Reduction in Industrial Computed Tomography
Authors:   Brno University of Technology (BUT), Zemek Marek ,   Brno University of Technology (BUT), Salplachta Jakub ,   Brno University of Technology (BUT), Zikmund Tomáš ,   Brno University of Technology (BUT), Kaiser Jozef
Published: February 2023

In computed tomography, artifacts caused by metal objects pose a major challenge, as they severely degrade the final image. Reduction of these artifacts is a topic of ongoing research, and many possible approaches have been developed so far. Among these, projection completion methods are effective and reasonably simple to implement compared to others. The most effective of these methods require a prior image, a synthetic, artifact-free representation of the data. This prior is used to recover data obscured by the metals and thus reduce the presence of potential secondary artifacts, but it may not be trivial to obtain especially in industrial computed tomography, where sample variability tends to be high. Traditional methods of prior generation are often based on multi-segmentation of a preliminary tomographic slice, which requires substantial a-priori knowledge about the scanned sample, its morphology, and the materials it is made of. This is a major limit for applications where such information is not readily available. Initial results for a more flexible method of prior image generation based on sinogram decomposition are presented here. The goal of this method is to decrease the need to fine-tune parameters for different samples and make it possible to use existing advanced metal artifact reduction methods in new fields.
TALINT grating kits for X-ray interferometry in the industrial laboratory
Authors:   Microworks Gmbh, Nafre Aishwarya ,   Upper Austrian University of Applied Sciences (FH OÖ), Glinz Jonathan ,   Karlsruhe Institute of Technology (KIT), Schulz Joachim ,   Upper Austrian University of Applied Sciences (FH OÖ), Senck Sascha
Published: February 2023

For the past century, X-ray imaging has been based on the attenuation of photon beams in a sample. Over the last few years, new imaging techniques called as X-ray phase contrast and dark field imaging have emerged. This method relies on the differential phase shifts of the X-ray wave on electron density gradients or on scattering in the sample. Phase effects enable enhanced imaging contrast for low ‘Z’ materials like plastics, carbon composites or even light metals and alloys. One of the principles for dark field imaging is Talbot-Lau Interferometry which is based on using three gratings. During the past decade, Microworks has produced high contrast gratings using the X-ray LIGA technique. Recently Microworks has started to develop mounting kits for Talbot-Lau interferometers as a product line, TALINT series. The first generation of the TALINT has been implemented at the University of Applied Sciences Upper Austria. Some industrially relevant applications with this system will be discussed in this paper. The subsequent version of the TALINT also known as TALINT EDU has also been discussed briefly in the last section of this paper.
The combined use of X-ray refraction and transmission radiography and computed tomography
Authors:   BAM Federal Institute for Materials Research and Testing, Bruno Giovanni ,   BAM Federal Institute for Materials Research and Testing, Laquai René ,   BAM Federal Institute for Materials Research and Testing, Wieder Frank ,   BAM Federal Institute for Materials Research and Testing, Kupsch Andreas ,   BAM Federal Institute for Materials Research and Testing, Müller Bernd Randolf
Published: February 2023

Alternative to conventional transmission-based radiography and computed tomography, X-ray refraction techniques are being increasingly used to detect damage in light materials. In fact, their range of application has been recently extended even to metals. The big advantage of X-ray refraction techniques is that they are able to detect nanometric defects, whose size would lie below the resolution of even state-of-the-art synchrotron-based X-ray computed tomography (SXCT). The superiority of synchrotron X-ray refraction radiography and tomography (SXRR and SXRCT) has been shown in the case of light materials, in particular composites. X-ray refraction techniques also yield a quantitifaction of the amount of damage (the so-called relative internal specific surface) and can well be compared with damage models. At the same time, it is impossible for SXRR and SXRCT to image single defects. We show that the combination of refraction- and transmission-based imaging techniques yields an impressive amount of additional information about the type and amount of defects in microstructured materials such as additively manufactured metals or metal matrix composites. We also show that the use of data fusion techniques allows the classification of defects in statistically significant representative volume elements.
Non-destructive characterization of out-of-plane fiber waviness in carbon fiber reinforced polymers by X-ray dark-field radiography
Authors:   Upper Austrian University of Applied Sciences (FH OÖ), Glinz Jonathan ,   Julius-Maximilians-University Würzburg, Zabler Simon ,   Upper Austrian University of Applied Sciences (FH OÖ), Thor Michael ,   Upper Austrian University of Applied Sciences (FH OÖ), Kastner Johann ,   Upper Austrian University of Applied Sciences (FH OÖ), Senck Sascha
Published: February 2023

Fibre waviness is a frequently encountered problem in composite design and manufacturing as it can severely influence mechanical properties of components. In this work we propose a new method for the detection and quantification of out-of-plane fibre waviness in carbon fibre composites using Talbot-Lau grating interferometry. The sensitivity of X-ray dark-field imaging to the orientation of carbon fibres is exploited to visualize fibre waviness by radiographic imaging and reduce measurement times in comparison to full computed tomography scans. We show that fibre waviness can be qualitatively detected by single radiographic images providing a valid option, e.g. for in-line monitoring of similar specimens. Furthermore, quantitative evaluation of fibre waviness angles can be performed by repeated radiographic imaging over an angular range of roughly 10°. Therefore, the number of required projection images can be reduced significantly. With this method, we evaluated wave angles at an error of less than ±1.5° compared to results achieved by full computed tomography scans.
AI-Supported Segmentation of Industrial CT Data
Authors:   University of Passau, Lang Thomas ,   University of Passau, Sauer Tomas
Published: February 2023

The segmentation of datasets has always been a vital part of many image or volume processing applications, especially regarding tomography data. Common approaches nowadays use either manually tuned methods or rely on techniques like Deep Learning. However, such methods often are useful for segmenting only components of a certainly well-defined type which mostly suffices for clinical data but not for industrial applications anymore. In order to overcome these limitations we propose an interactive approach to volumetric segmentation encompassing robust classifiers and localized volume processing. The resulting algorithm is flexible enough to be used for a broad variety of different segmentation tasks while still generating high quality results. The local processing further enables the segmentation of larger volumes which cannot be handled by existing applications.
Effect of detector in-plane rotation misalignment on dimensional measurements using helical CT acquisition.
Authors:   Brno University of Technology (BUT), Blažek Pavel ,   Brno University of Technology (BUT), Břínek Adam ,   Brno University of Technology (BUT), Varslot Trond ,   Brno University of Technology (BUT), Zikmund Tomáš ,   Brno University of Technology (BUT), Kaiser Jozef
Published: February 2023

One of the critical factors that may significantly contribute to X-ray computed tomography measurement uncertainty is the misalignment of CT system components from ideal geometry assumed by tomographic reconstruction. It is proven to cause image artifacts, inhomogeneous magnification, thus leading to dimensional measurement errors. There is a lack of studies on helical trajectory scanning in metrological applications, focusing on the detector's angular misalignments. We will present results of CT measurements with misaligned detector by in-plane rotation for circular, double-helix, and space-filling trajectory. They prove that such misalignment may cause significant measurements errors, depending on the misalignments magnitude and applied acquisition trajectory.
Discrete Terahertz tomography: a simulation study
Authors:   University of Antwerpen, Christopher Jana ,   University of Antwerpen, Lumbeeck Lars-Paul ,   University of Antwerpen, Paramonov Pavel ,   University of Antwerpen, De Beenhouwer Jan ,   University of Antwerpen, Sijbers Jan
Published: February 2023

As Terahertz (THz) technology becomes more prominent in the imaging industry, there is a rising need for improved reconstruction techniques for THz tomographic imaging. Conventional reconstruction techniques yield artifacts for limited data problems, hindering further analysis of the reconstruction. In this paper, we explore a discrete reconstruction algorithm for Terahertz tomography, which exploits prior knowledge on the gray levels in the imaging data of the object to obtain high quality reconstructions. Simulations show that, compared to THz-SIRT reconstruction, the discrete THz algorithm (THz-DART) generates more accurate reconstructions, especially when only a small number of projections or projections acquired within a limited angular range are available.
Improving the dimensional accuracy of computed tomography data obtained with high-resolution 3D X-ray microscopes
Authors:   Carl Zeiss Industrial Metrology, Villarraga-Gómez Herminso ,   Carl Zeiss X-ray Microscopy, Kotwal Naomi ,   Carl Zeiss X-ray Microscopy, Parwani Rachna ,   Carl Zeiss, Omlor Lars ,   Carl Zeiss X-ray Microscopy, Johnson Bruce ,   Carl Zeiss Industrielle Messtechnik GmbH, Zarnetta Robert ,   Carl Zeiss Industrielle Messtechnik GmbH, Weiß Daniel ,   Carl Zeiss Industrielle Messtechnik GmbH, Kimmig Wolfgang ,   Carl Zeiss X-ray Microscopy, Graf vom Hagen Christoph
Published: February 2023

Today, 3D X-ray microscopes (XRMs) have the unique ability to achieve higher resolution, non-destructive imaging, within larger parts than traditional X-ray micro computed tomography (CT) systems. Such unique capability is, more and more, of interest to industrial quality control entities as they grapple with small features in precision manufactured parts for various industries such as automotive, electronics, aerospace, medical devices, and additive manufacturing, to name a few examples.
Fully volumetric tracking of melting fronts in phase change materials with computed tomography
Authors:   Lucerne University of Applied Sciences and Arts (HSLU), Martinez-Garcia Jorge ,   Lucerne University of Applied Sciences and Arts (HSLU), Gwerder Damian ,   Lucerne University of Applied Sciences and Arts (HSLU), Wahli Fabian ,   Lucerne University of Applied Sciences and Arts (HSLU), Guarda Dario ,   Lucerne University of Applied Sciences and Arts (HSLU), Stamatiou Anastasia ,   Lucerne University of Applied Sciences and Arts (HSLU), Fischer Ludger J. ,   Lucerne University of Applied Sciences and Arts (HSLU), Worlitschek Jörg ,   Lucerne University of Applied Sciences and Arts (HSLU), Schütz Philipp
Published: February 2023

Recent advances in laboratory X-ray computed tomography (XCT) enabled short acquisition times on the order of a few minutes, which enable the investigation of dynamic processes in-situ by time-lapse measurements. These advances open new opportunities for revealing information on the solid-liquid phase transformation occurring in phase changes materials (PCMs), which are a promising solution for designing compact latent thermal energy storage systems (LTES). In this contribution we report results obtained from the XCT System, “LuCi”, recently installed at Lucerne university of Applied Sciences and Arts, where the evolution of the melting process in an ice cube confined within a cylindrical, X-ray transparent sample holder is tracked. Our results indicate that even tiny differences of a few percent in the density of the two different phases can be differentiated in XCT measurements. The high-power X-ray source and a fast X-ray detector of LuCi enable the acquisition of a XCT measurement in a short period (< 1 – 6 minutes). By using proper image processing methods, estimates for the volumetric melting rate, the local melting front velocity, and the tree dimensional (3D) shape of the melting front were obtained from the four-dimensional (4D) imaging data. These results will help to build more efficient thermal energy storage systems in the future, which will support the energy turnaround.
Traceable determination of non-static XCT machine geometry: New developments and case studies
Authors:   Federal Institute of Metrology METAS, Bircher Benjamin A. ,   Federal Institute of Metrology METAS, Meli Felix ,   Federal Institute of Metrology METAS, Küng Alain ,   BAM Federal Institute for Materials Research and Testing, Bellon Carsten ,   BAM Federal Institute for Materials Research and Testing, Evsevleev Sergei ,   University of Zagreb, Katic Marko ,   VTT Technical Research Centre of Finland, Heikkinen Ville ,   VTT Technical Research Centre of Finland, Hemming Björn ,   VTT Technical Research Centre of Finland, Lassila Antti
Published: February 2023

It is fundamental to determine the machine geometry accurately for dimensional X-ray computed tomography (XCT) measurements. When performing high-accuracy scans, compensation of a non-static geometry, e.g. due to rotary axis errors or drift, might become necessary. Here we provide an overview of methods to determine and account for such deviations on a per projection basis. They include characterisation of stage error motions, in situ geometry measurements, numerical simulations, and reconstruction-based optimization relying on image quality metrics and will be discussed in terms of their metrological performance. Since a radiographic calibration is always required to provide an initial absolute geometry, this method will be presented as well. The improvements of the XCT geometry correction methods are presented by means of case studies. The methods can be applied individually or in combination and are intended to provide a toolbox for XCT geometry compensation.
Geometric errors of CT scanners and their estimation by imaging a reference object
Authors:   Federal University of ABC (UFABC), Baldo Crhistian Raffaelo ,   Catholic University of Leuven (KU Leuven), Probst Gabriel Maurício ,   Catholic University of Leuven (KU Leuven), Dewulf Wim
Published: February 2023

Computed Tomography (CT) has been included in the routine of the dimensional quality loop of manufactured products over the past two decades. Characterized by a complex measurement chain, many influence factors may affect the accuracy of CT measurements. Misalignments stemming from imperfections of the components of the CT metrology instrument exemplify an influence factor over which the user may have no control. In this regard, this paper describes the experimental study of the geometric errors of a CT instrument using an image-based method to map them. The experiments were designed with the purposes of understanding the time-related variation pattern of the geometric errors and assessing the actual measurement capability of the image-based method itself to discriminate the geometric errors. The experimental findings can contribute to an optimized use of the CT technology for dimensional measurements, for example, by assisting the proper actions to be taken by the user for error correction.
Digital Twin for Region-of-Interest Computed Tomography of Additive Manufactured Components using an Industrial Robot
Authors:   VisiConsult X-ray Systems & Solutions GmbH, Dedyaeva Polina ,   VisiConsult X-ray Systems & Solutions GmbH, Krohne Kristen ,   VisiConsult X-ray Systems & Solutions GmbH, Herold Frank
Published: February 2023

Computed tomography (CT) is often used as a non-destructive testing (NDT) method to analyze the internal structure of safetycritical parts, e.g. in the automotive or aerospace industries. Additively manufactured (AM) components in particular often result in very complex structured parts due to their bionic design, which are lightweight and thus reduce the CO2 emissions of cars or aircrafts. For metallic AM components produced in a powder bed fusion process pores, inclusions or lack-of-fusion errors (LoF) may occur typically. The latter one arises if powder could not be melted properly, i.e., it is an inclusion of loose powder inside the part. Such LoF are very low in contrast compared to the surrounding solid material and therefore harder to detect the smaller they are and the thicker the penetrated material is. Monitoring systems integrated in the 3D-Printer help to detect indications of where a defect could have occurred. Exactly on each of these predefined positions the CT-System will do a region-of-interest scan (ROI scan). In this study we are using an industrial robot as manipulator of the component to overcome the limitations of traditional CT setups. Its dedicated trajectory using only the optimal projection directions of the current ROI is derived by using our newly developed Digital Twin containing the robot, the AM component and the X-Ray imaging chain. In this study we will show how the simulation is used to find optimal projection directions and a first CT scan of the robot will be demonstrated.
High-accuracy Surface Extraction Using the High-order differentiation of X-ray CT Values
Authors:   Tokyo Metropolitan University, Ota Tomoya ,   Tokyo Metropolitan University, Nagai Yukie ,   The University of Tokyo, Ohtake Yutaka ,   Tokyo Metropolitan Industrial Technology Research Institute, Monkawa Akira ,   Tokyo Metropolitan Industrial Technology Research Institute, Miura Yuka ,   Tokyo Metropolitan Industrial Technology Research Institute, Gessei Tomoko
Published: February 2023

In manufacturing, accurate shape acquisition of products (such as dimensional evaluation and defect detection) provides assurance of product quality. One prominent geometry-acquisition method is X-ray computed tomography (CT), which non-destructively obtains the three-dimensional data (i.e., a CT volume) of the internal geometry of an object. Within a CT volume, the CT values of the voxels are proportional to the local densities of the object. Because a CT volume is a discrete dataset, an X-ray CT scan can not potentially meet the accuracy requirement due to discretization error. In this paper, we extract the surface of an object with high accuracy of about one-tenth of the voxel size by defining a surface point as a point at which the differentiation of the gradient norm of the CT value in the gradient direction is zero. This method uses analytical differentiations of the CT values that are directly computed from the X-ray projection values, which are less affected by CT-reconstruction artifacts than the discrete differentiations computed the CT volume. In an experimental analysis, we show that this algorithm can extract the surface more accurately than conventional methods.
Towards automatic crack segmentation in 3d concrete images
Authors:   Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau (RPTU) former Technische Universität Kaiserslautern, Jung Christian ,   Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau (RPTU) former Technische Universität Kaiserslautern, Müsebeck Franziska ,   Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau (RPTU) former Technische Universität Kaiserslautern, Barisin Tin ,   Fraunhofer-Institut für Techno- und Wirtschaftsmathematik (ITWM), Schladitz Katja ,   Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau (RPTU) former Technische Universität Kaiserslautern, Redenbach Claudia ,   Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau (RPTU) former Technische Universität Kaiserslautern, Kiesche Martin ,   Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau (RPTU) former Technische Universität Kaiserslautern, Pahn Matthias
Published: February 2023

Concrete is one of the most commonly used construction materials. A deeper insight into its mechanical properties, in particular cracking behaviour, can be gained from stress tests. Computed tomography captures the microstructure of building materials, including crack initiation and propagation in a fully three-dimensional manner. However, the complex microstructure of concrete renders crack segmentation a very challenging task. Both, the validation of segmentation methods and the training of machine learning approaches, are hindered by the lack of reliable ground truth segmentations for real data sets. To overcome this problem, a novel procedure for generating pairs of semi-synthetic images and ground truth was introduced by the authors in a previous study. Using this semi-synthetic data, Hessian-based percolation and 3d U-net were identified as the most promising of eight approaches for crack segmentation. Here, we discuss adaptions of the methods that allow for a handling of additional features observed in real computed tomography data of concrete, in particular local variations in crack thickness.
Assessing the influence of CT acquisition parameters on flaw detectability through simulation
Authors:   Commissariat Energie Atomique (CEA), Vienne Caroline ,   University Paris-Saclay, Escoda Julie ,   Commissariat Energie Atomique (CEA), Touron Anthony ,   Commissariat Energie Atomique (CEA), Costin Marius
Published: February 2023

X-Ray Computed Tomography (XCT) is a unique tool to fully visualize and understand the nature and size of flaws in industrial parts, with a growing application in different fields such as aeronautics and more recently metal additive manufacturing. The inevitable questions underlying any XCT inspection concern the detectability limit of the measure. What size of defect will be detected with my current configuration? How can I optimize my acquisition material or parameters to improve the detectability limit? Naturally, the known characteristics of the XCT systems (detector pixel size, X-ray tube voltage and focal spot size, magnification) give a first answer to these questions, at least in terms of spatial resolution, but it is more difficult to estimate a priori the visibility of a flaw in terms of contrast. The cost of XCT inspection, the difficulty to design specimen with narrow internal defects and the influence of the geometry of the part on the XCT image quality make experimental analysis of the detectability limits difficult. The simulation brings therefore a promising alternative, provided that it gives a thorough representation of a real inspection.
Artefacts from off-focal X-rays in tomography of highly attenuating objects
Authors:   The Australian National University, Kingston Andrew M. ,   The Australian National University, Grewar Murdock ,   The Australian National University, Beeching Levi ,   The Australian National University, Fullagar Wilfred ,   The Australian National University, Slama Marek ,   The Australian National University, Sheppard Adrian P.
Published: February 2023

At CTLab we have recently commissioned a 300keV x-ray tomography system capable of imaging metallic parts and rock cores with diameters over 100mm. This new imaging regime manifests artefacts in the reconstructed tomographic volumes that resemble those from incoherent x-ray scatter from the object. However, through the experimental investigation outlined herein, we have determined these artefacts to be primarily due to off-focal, or secondary, x rays emitted from the x-ray source. All micro-focus x-ray sources tested, (both transmission and reflection targets), exhibited off-focal x rays to a greater or lesser extent (6 different x-ray source models from 4 different manufacturers). We also demonstrate that off-focal x rays may have received limited attention to date since the artefacts they cause are only severe for highly attenuating samples. Here our aim is to fully understand and characterise this phenomenon in order to incorporate it into the imaging model and mitigate the associated artefacts in computed tomography.
Comparison of post-process X-ray computed tomography and in-process optical measurements for defects evaluation in additively manufactured metal parts
Authors:   University of Padova (UNIPD), Bonato Nicolò ,   University of Padova (UNIPD), Zanini Filippo ,   University of Padova (UNIPD), Carmignato Simone
Published: February 2023

Despite the capability of fabricating complex and customized components, metal laser powder bed fusion (LPBF) is still affected by manufacturing issues, which can lead to significant geometrical and dimensional errors and internal defects. These aspects can represent a major barrier to a wider industrial application of LPBF, particularly if considering that relevant applications of additive manufacturing are in sectors such as biomedical and aerospace, which have stringent requirements in terms of defects and product quality. The requests for precision improvement are orienting research activities towards the development of inprocess monitoring systems able to perform accurate analyses during the fabrication itself, hence providing useful information for improving the quality of produced parts. To this aim, several in-process monitoring methods have been proposed in the literature to identify and correct out-of-control process conditions. In spite of the aforementioned research efforts, work is still needed to reliably correlate in-process measurements to actual defects. The focus of this experimental study is the definition of a robust methodology to compare in-process optical acquisitions to post-process X-ray computed tomography (XCT) measurements of actual defects. XCT unique capabilities are therefore exploited to support and improve the LPBF process through the implementation of an accurate comparison methodology.
Comparison of preparation methods for the structural examination of meat using micro-computed tomography
Authors:   Upper Austrian University of Applied Sciences (FH OÖ), Pointner Tobias ,   Upper Austrian University of Applied Sciences (FH OÖ), Auer Jaqueline ,   Upper Austrian University of Applied Sciences (FH OÖ), Senck Sascha ,   Upper Austrian University of Applied Sciences (FH OÖ), Kastner Johann ,   Upper Austrian University of Applied Sciences (FH OÖ), Mathmann Katrin
Published: February 2023

In this contribution we used micro-computed tomography (micro-CT) to analyse the structural characteristics of turkey meat. In order to increase the contrast between muscle fibers and the surrounding tissue, three different preparation methods were tested. Firstly, the structure of the meat was examined in the frozen (F) state using a Deben cooling stage and in freeze-dried (FD) state. Secondly, samples were pretreated using a contrast agent (CA) (Lugol's iodine solution) to increase the contrast of muscle fibers. The shrinkage caused by the FD process was compared by quantitative analysis of the sample´s volume and the muscular structure proportion to total volume (MV/TV).
Influence of X-Ray Radiation on Historical Paper
Authors:   University of Erlangen-Nürnberg (FAU), Zippert Patrick ,   University of Erlangen-Nürnberg (FAU), Seuret Mathias ,   University of Erlangen-Nürnberg (FAU), Maier Andreas ,   University of Erlangen-Nürnberg (FAU), Hausotte Tino
Published: February 2023

Historical books are often so fragile that they cannot easily be opened in order to read the contents without damaging them. Current research shows, that industrial X-ray computed tomography (CT) can be used to examine closed historical manuscripts. However, the effect of X-rays on ancient paper has rarely been studied, making it difficult to assess the impact of CT measurements on fragile historical manuscripts in terms of additional destruction. To address this problem, various types of paper were exposed to high levels of X-ray radiation in order to examine them for change in optical properties. The investigations showed increasing yellowing due to the increased radiation energy. However, the severity of the yellowing is strongly dependent on the composition of the paper.
Multiscale In-situ Investigations of the Formation of Delamination in CFRP by Means of X-Ray Micro-Computed Tomography
Authors:   Upper Austrian University of Applied Sciences (FH OÖ), Höglinger Markus ,   Upper Austrian University of Applied Sciences (FH OÖ), Plank Bernhard ,   Upper Austrian University of Applied Sciences (FH OÖ), Thor Michael ,   Upper Austrian University of Applied Sciences (FH OÖ), Heinzl Christoph ,   Upper Austrian University of Applied Sciences (FH OÖ), Kastner Johann
Published: February 2023

Due to their potential of decreasing weight and emission, the importance of lightweight designs with carbon fibre reinforced polymers (CFRP) in the aeronautic and automotive industry is increasing constantly. However, the formation of cracks and delaminations is one of the most prominent failure mechanisms during mechanical loading of CFRP, significantly influencing the material’s behaviour. The effects range from no effect on the structure up to complete failure of the part. In order to assess the severity of the effects, a profound knowledge of the origin of delamination initiation, its evolution and dimension of delaminations is indispensable. To display the inner structures of the specimen, X-ray computed tomography (XCT) leads to three-dimensional images of the specimen under investigation. In a multiscale XCT approach, beginning with a lower resolution, a visualization of the position and, to a lesser extent, the dimension of the delamination can be obtained over the entire volume of the specimen. A detailed visualization of the initiation and propagation of delamination at stepwise increased loadings of the specimen is obtained with higher resolution measurements. With the aid of a simple wooden in situ loading setup, the whole process of delamination initiation and growth over a certain displacement can be monitored. These two approaches in combination with certain loading stages allows a detailed description of the performance of the specimen under load.
DTHE : Dual Tomograph for High Energy, a unique microCT platform.
Authors:   RX Solutions SAS, Valton Solène ,   National Institute of Applied Science ( INSA-Lyon)- University of Lyon, Maire Eric ,   National Institute of Applied Science ( INSA-Lyon)- University of Lyon, Lachambre Joël ,   National Institute of Applied Science ( INSA-Lyon)- University of Lyon, Papillon Justine ,   National Institute of Applied Science ( INSA-Lyon)- University of Lyon, Adrien Jérôme
Published: February 2023

Challenges in X-ray microCT are growing as fast as the technology. MATEIS Laboratory has recently received a new microCT platform developed by RX Solutions with unique features worldwide. The DTHE, stating for Dual Tomograph for High Energy will cover some of these challenges. The double tomograph is designed around one rotation axis and two 300 kV Xray lines. The platform will allow microCT scans with voxel size ranging from 4 µm to few hundreds of microns, with simultaneous or sequential acquisition, with identical or distinct resolution, with identical or distinct energy, with or without external solicitation, etc... The goal of the platform is to open wide the research and development on dense or large samples thanks to microCT at high resolution and high energy. Beyond the very first and obvious advantages of such a system, the researchers will be able to dig deep into new and unexplored CT possibilities. Recently started, this paper gives a description of the system and the perspectives it offers.
Global digital volume correlation of large volumes: a sub-volume adaptive meshing approach
Authors:   University of Manchester at Harwell, Léonard Fabien ,   University of Manchester at Harwell, Cornet Antoine ,   University of Manchester at Harwell, Bourne Neil
Published: February 2023

While global Digital Volume Correlation (DVC) yields more accurate results compared to local DVC, its main drawback remains the computational power needed to store and update the entire reference and deformed volumes during the optimisation process. This effectively prevents the use of global DVC for large volumes, with the exact size limit depending on the accessible RAM of the workstation or server running the DVC algorithm. This paper presents a development made at the University of Manchester at Harwell to perform a global DVC on X-ray Computed Tomography (XCT) volumes larger than the capabilities of a given computer hardware. The method relies on dividing the large meshed volume into smaller overlapping volumes, and corresponding meshes, that can be handled successively by the computer hardware to perform global DVC. Then, the nodes in the overlapping regions are assessed and the resulting sub-volumes global DVC results are merged into a single output result file covering the entire XCT volume. Overall, this sub-volume adaptive meshing approach is a solution to overcomes hardware limitations in cases where global DVC is required over large volumes and meshing density can be user-defined to fit the expected damage location within the sample.
Automatic scan planning for CT scans
Authors:   Fraunhofer Institute for Integrated Circuits (IIS), Kretzer Christian ,   Fraunhofer Institute for Integrated Circuits (IIS), Schielein Richard ,   Fraunhofer Institute for Integrated Circuits (IIS), Sukowski Frank ,   Fraunhofer Institute for Integrated Circuits (IIS), Daniel Suth ,   Fraunhofer Institute for Integrated Circuits (IIS), Berg Michael ,   Fraunhofer Institute for Integrated Circuits (IIS), Waldyra Adrian
Published: February 2023

Today, Computed Tomography is becoming increasingly important as a non-destructive testing technique in industry. The advantages of evaluating 3D information are manifold and system costs have fallen in recent years. However, these systems suffer from the disadvantage that performing a measurement is more complex and error-prone than pure radioscopic testing. Thus, users with more skill and experience are needed to get the most out of the scan. Nowadays, the process of parametrizing the CT scan is often completely manual and mostly performed by inspection engineers due to the high number of available parameters. These are spatial resolution, magnification, object and detector distances, number of projections and, most importantly, positioning of the specimen on the turntable. Choosing appropriate parameters is not trivial due to the interplay between required image quality and scan time. So, identifying optimal parameters can be a major challenge. The main goal of the scan planning is to solve the scan task dependably, process-safely if applicable, and efficiently with minimal investment of time. Simulation-based determination of the optimal parameters can enable objective parameters to be obtained that are less depended on expert users. This is especially important when a wide variety of objects need to be scanned. 3D printed parts, which can have a batch size of one under extreme conditions, serve as an example. The range of parts produced is extremely wide and complex, which leads to a complex configuration of the scan. Fraunhofer EZRT is developing software solutions to find an ideal scanning trajectory for a given scan task. For this purpose, CAD data of the part is used to simulate CT reconstructions and to evaluate the suitability of the parameters in focus of the task. For this, the image quality of the component, for metrological task e.g., and the detectability of faults inside the material, pores e.g., are considered. The user is given the ability to provide the parameter space especially with the regard to the geometry of the system. Also, the user can define quality criteria, pore sizes in different component locations e.g., which are considered in the optimization process. In the first step, those parameter sets are selected which have the best ratings on a projection basis. Subsequently, reconstructions are made on the remaining candidates, and these are evaluated. This approach saves computational time, the entire parameter space can be sampled, and a meaningful evaluation of the expected reconstruction can be performed.
Development of Projection X-ray Microscope with 100 nm Spot Size
Authors:   Nikon Corporation, Matsunaga Norihito ,   Nikon Corporation, Sato Tomoya ,   Nikon Corporation, Higuchi Kota ,   Nikon Corporation, Yamada Atsushi
Published: February 2023

A projection X-ray microscope useful for industrial non-destructive inspections and various biological observations has been developed. By installing a Schottky type electron source, a nano focus X-ray source with 100 nm focal spot size that is easy to handle in various laboratories is successfully achieved at 20 to 80 kVp. An imaging system has been composed of a vertical type that can adjust a sample position on the optical axis, and high-resolution imaging can be achieved by using a high precision stage unit. A test chart with 200 nm line width can be clearly confirmed by a transmission image, and CT images with high spatial resolution were also obtained for a test sample of glass containing air micro-bubbles. Finally, we confirmed that the spatial resolution of the obtained CT images does not contradict the measurement conditions by using the evaluation formula of spatial resolution including the effect of X-rays diffraction.
High-resolution CT simulation of synthetically-generated volume porosity in continous CFRP samples
Authors:   Upper Austrian University of Applied Sciences (FH OÖ), Plank Bernhard ,   Upper Austrian University of Applied Sciences (FH OÖ), Kastner Johann
Published: February 2023

In this study new insights regarding quantitative porosity determination using X-ray computed tomography (CT) could gained by using CT simulation tools to generated synthetical 3D data with a well known nominal porosity content. Therefore 1,988 typical microstructure elements such as individual carbon fibres, needle like micro voids as well some macro voids embeded in a polymer matrix (epoxy resin & polyamid 6) was used as geometrical imput. The results of the threshold-based segmentation methods in this paper are in good agreement with similar experimental results previously published by the authors.
Visualization Techniques for the Comparative Analysis of Multivariate Data of Fiber Reinforced Polymers
Authors:   Upper Austrian University of Applied Sciences (FH OÖ), Heim Anja ,   Upper Austrian University of Applied Sciences (FH OÖ), Maurer Julia ,   Upper Austrian University of Applied Sciences (FH OÖ), Kastner Johann ,   Upper Austrian University of Applied Sciences (FH OÖ), Heinzl Christoph
Published: February 2023

The comparative analysis of data from multiple candidate material systems is essential for the improvement and development of advanced composite materials. Since the characteristics (e.g., length, orientation) of individual objects (e.g., pores, fibers) are crucial for the properties and the behavior of materials, the exploration of these is of utmost importance. Currently, the comparison of these multivariate, numerical data requires significant mental efforts, since the experts have to perform a sequential comparison of many slightly different charts. This work aims to simplify the workflow for comparing many datasets by providing experts with an interactive visualization framework. By combining different representations at various levels of detail, it assists users to get a holistic view on the similarities of the objects and their characteristics. An overview visualization allows to determine the similarity of the objects of several samples, additional detail visualizations give the user detailed information about groups of similar structures. We demonstrate the applicability of our tool on two use cases, a fiber material subjected to an in situ test, and a comparative study of multiple pore datasets.
Comparison campaign of XCT systems using machined standards representative of additively manufactured parts
Authors:   Laboratoire National de Métrologie et d'Essais (LNE), Obaton Anne-Françoise ,   Technical University of Denmark (DTU), Quagliotti Danilo ,   Laboratoire National de Métrologie et d'Essais (LNE), Yardin Catherine ,   Technical University of Denmark (DTU), Liltorp Klaus ,   Technical University of Denmark (DTU), De Chiffre Leonardo
Published: February 2023

Additive manufacturing enables the production of complex geometries, both internally and externally. This poses a challenge to quality control. Non-destructive volumetric testing methods are required. Among these methods, X-ray computed tomography is currently the most promising. It enables not only to detect inner and outer defects but also to perform dimensional measurements. However, the method lacks of metrological tracability. To fill this gap, an EMPIR project 17IND08 AdvanCT involving several European countries was proposed. In this frame, DTU Mekanik and LNE have conducted a comparison campaign of XCT systems using machined material measures representative of additively manufactured parts. The purpose of the comparison was to investigate the performances of industrial X-ray computed tomography with respect to dimensional measurements on external but also on internal features.
Development of a novel gauge filled with resin for X-ray CT
Authors:   National Institute of Advanced Industrial Science and Technology (AIST), Watanabe Mari ,   National Institute of Advanced Industrial Science and Technology (AIST), Matsuzaki Kazuya ,   National Institute of Advanced Industrial Science and Technology (AIST), Sato Osamu ,   National Institute of Advanced Industrial Science and Technology (AIST), Telada Souichi ,   National Institute of Advanced Industrial Science and Technology (AIST), Takatsuji Toshiyuki
Published: February 2023

X-ray computed tomography (CT) systems have been widely used for three-dimensional (3D) measurements in the engineering field. Therefore, verifying X-ray CT systems with full traceability is necessary to ensure accurate measurements. Measurement errors of X-ray CT systems are evaluated using a reference gauge whose geometry is calibrated using 3D measuring systems with higher accuracy. Thus, this study developed and characterized a novel reference gauge for X-ray CT systems, comprising spheres embedded in a cylindrical resin.
Benchmarking of different reconstruction algorithms for industrial cone-beam CT
Authors:   University Paris-Saclay, Rathore Jitendra Singh ,   Physikalisch-Technische Bundesanstalt (PTB), Laquai René ,   University College London (UCL), Biguri Ander ,   University of Bath, Soleimani Manuchehr ,   University Paris-Saclay, Vienne Caroline
Published: February 2023

In the field of industrial computed tomography, there have been a lot of interests in different reconstruction algorithms which could perform better than the standard FDK algorithm in non-ideal conditions leading to faster CT acquisitions. However, the computation efforts required by iterative algorithms are quite high, which makes them less practical in industrial environments. In this work, we propose a benchmark of the performances of various reconstruction algorithms using Tomographic Iterative GPU-based Reconstruction (TIGRE) toolbox; the benchmarking criteria used include both image quality metrics and taskoriented post-reconstruction results (measurements, porosity, etc.). Furthermore, we have also tested their performances with limited projections and limited angular range to facilitate faster CT acquisitions. The preliminary results indicate several improvements in the reconstructions (better feature definitions) with one of the iterative algorithms (CGLS: conjugate gradient least squares) as compared to FDK.
VERTEX – versatile in-situ testing rig for X-ray scanners
Authors:   Czech Academy of Sciences (CAS), Fila Tomas ,   Czech Academy of Sciences (CAS), Rada Vaclav ,   Czech Academy of Sciences (CAS), Zlamal Petr ,   Czech Academy of Sciences (CAS), Koudelka Petr ,   Czech Academy of Sciences (CAS), Kytýr Daniel
Published: February 2023

In this contribution, we introduce a next-generation in-situ loading stage VERTEX (VERsatile in-situ TEsting rig for X-ray scanners) allowing for both high load capacity and high resolution tomographical imaging in a broad range of experiments including uni-axial, flexural, torque testing, and their combinations. The device is designed as a double column testing rig with two individually controlled rotary stages. It consists of 6 individual function blocks (two loading columns, two rotary stages, two cross-head beams) ensuring easy manipulation and reasonable portability. The function blocks can be assembled into different geometrical configurations (uni-axial on-axis, uni-axial off-axis, flexural) while additional loading modules can be mounted onto the rotary stages (e.g., voice coil vibration loading stage). In comparison with the conventional existing devices having the identical arrangement (two columns, two rotary stages), the loading capacity of the VERTEX is several times higher while dimensions and robustness of the device still do not significantly limit the achievable resolution.
Improving throughput and image quality of high-resolution 3D X-ray microscopes using deep learning reconstruction techniques
Authors:   Carl Zeiss Industrial Metrology, Villarraga-Gómez Herminso ,   Carl Zeiss X-ray Microscopy, Norouzi Rad Mansoureh ,   Carl Zeiss X-ray Microscopy, Andrew Matthew ,   Carl Zeiss X-ray Microscopy, Andreyev Andriy ,   Carl Zeiss X-ray Microscopy, Sanapala Ravikumar ,   Carl Zeiss, Omlor Lars ,   Carl Zeiss X-ray Microscopy, Graf vom Hagen Christoph
Published: February 2023

In high-resolution X-ray computed tomography (CT), also known as 3D X-ray microscopy (XRM), low photon counts can lead to extremely long data acquisition times (in the order of hours). Reducing the number of radiographic projections (Np) acquired for CT reconstruction can be a cost-efficient solution in some cases. But the risk associated with reducing Np, if analytical filteredbackprojection algorithms are used for CT reconstruction, e.g., Feldkamp-Davis-Kress (FDK), is that it may produce a significant loss of image quality. Typical Np thresholds for a faithful 3D image reconstruction, required by the Nyquist-Shannon sampling theorem, are in the order of thousand projection views with modern XRM instruments. It is now well known, however, that deep learning (DL) based algorithms for CT reconstruction can improve the scan time (throughput) and image quality capabilities of XRM. This paper proposes the use of DL-based algorithms as an option for reducing Np, even down to a few hundred projections, without a significant loss of image quality. The integration of DL-based reconstruction techniques into 3D XRM workflows is presented throughout this article. It is shown that 3D XRM data reconstructions produced by DL-based workflows can provide up to 8X and 10X throughput improvement at similar or better image quality compared to standard FDK reconstruction.