On the use of X-ray computed tomography for determining wood properties: a review1This article is a contribution to the series The Role of Sensors in the New Forest Products Industry and Bioeconomy.

2011 ◽  
Vol 41 (11) ◽  
pp. 2120-2140 ◽  
Author(s):  
Qiang Wei ◽  
Brigitte Leblon ◽  
Armand La Rocque
Keyword(s):  
Computed Tomography ◽  
Growth Ring ◽  
Back Propagation ◽  
Forest Products ◽  
Ct Images ◽  
Ct Scanner ◽  
Forest Products Industry ◽  
X Ray ◽  
Feed Forward Back Propagation ◽  
X Ray Computed

In several processes of the forest products industry, an in-depth knowledge of log and board internal features is required and their determination needs fast scanning systems. One of the possible technologies is X-ray computed tomography (CT) technology. Our paper reviews applications of this technology in wood density measurements, in wood moisture content monitoring, and in locating internal log features that include pith, sapwood, heartwood, knots, and other defects. Annual growth ring measurements are more problematic to be detected on CT images because of the low spatial resolution of the images used. For log feature identification, our review shows that the feed-forward back-propagation artificial neural network is the most efficient CT image processing method. There are also some studies attempting to reconstruct three-dimensional log or board images from two-dimensional CT images. Several industrial prototypes have been developed because medical CT scanners were shown to be inappropriate for the wood industry. Because of the high cost of X-ray CT scanner equipment, other types of inexpensive sensors should also be investigated, such as electric resistivity tomography and microwaves. It also appears that the best approach uses various different sensors, each of them having its own strengths and weaknesses.

scholarly journals Evaluation of Microstructure and Transport Properties of Deteriorated Cementitious Materials from Their X-ray Computed Tomography (CT) Images

Materials ◽  
2016 ◽  
Vol 9 (5) ◽  
pp. 388 ◽  
Author(s):  
Michael Promentilla ◽  
Shermaine Cortez ◽  
Regina Papel ◽  
Bernadette Tablada ◽  
Takafumi Sugiyama
Keyword(s):  
Computed Tomography ◽  
Transport Properties ◽  
Cementitious Materials ◽  
Ct Images ◽  
X Ray ◽  
X Ray Computed

scholarly journals Quantitative Evaluation of Soil Structure and Strain in Three Dimensions under Shear Using X-ray Computed Tomography Image Analysis

2021 ◽  
Vol 7 (11) ◽  
pp. 230
Author(s):  
Shintaro Nohara ◽  
Toshifumi Mukunoki
Keyword(s):  
Computed Tomography ◽  
Image Analysis ◽  
Shear Zone ◽  
Soil Structure ◽  
Three Dimensions ◽  
Image Correlation ◽  
Ct Scanner ◽  
Zone Formation ◽  
X Ray ◽  
X Ray Computed

The objective of this study is to quantitatively evaluate the soil structure behavior when under shear stress to understand the mechanism of shear zone formation using a micro-focus X-ray computed tomography (CT) scanner to visualize the internal samples without causing disturbance. A new image-analysis method was proposed to systematically evaluate the particle length and direction by fitting the particle as an ellipsoid. Subsequently, a direct shear experiment was conducted on soil materials, and shear band was scanned using a micro-focus X-ray CT scanner. After validating the proposed method, the soil structure was evaluated in the shear zone via image analysis on the CT images. Furthermore, the strain inside the specimen was evaluated using digital image correlation. The results showed that a partial change in the particle direction occurred when the volume expansion inside the shear zone exceeded the peak. In addition, the width of the shear zone was ~7.1 times the median grain size of the sand used; however, the region exhibiting a change in the direction of the particles was narrow and confined to the vicinity of the shear plane.

scholarly journals Using X-Ray CT Scanning to Study the Failure Mechanism of Concrete under Static and Dynamic Loadings

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Guangyu Lei ◽  
Jichang Han ◽  
Faning Dang
Keyword(s):  
Computed Tomography ◽  
Failure Mechanism ◽  
Static Load ◽  
Ct Scanning ◽  
Ct Images ◽  
X Ray ◽  
Dynamic Loadings ◽  
Ultimate Failure ◽  
X Ray Computed ◽  
Straight Lines

X-ray images can be used to nondestructively monitor the initiation, extension, and combination of cracks in concrete. In this study, real-time X-ray computed tomography (CT) scanning of concrete specimens under static and dynamic loadings was done. The CT images showed the growth, propagation, and penetration of the cracks and showed the ultimate failure of the concrete samples. Analysis of the CT images and CT numbers showed that the failure followed the structure’s areas of weakness under the static load, but for dynamic loading, the cracks formed very rapidly along straight lines through the aggregate.

scholarly journals Computer Based X-Ray Computed Tomography Training System for Engineering Education

2017 ◽  
Vol 9 (3-2) ◽  
Author(s):  
Muhammad Hanif Ramlee ◽  
Jasmy Yunus ◽  
Eko Supriyanto
Keyword(s):  
Computed Tomography ◽  
Imaging Modality ◽  
Training System ◽  
Radiation Hazard ◽  
Ct Scanner ◽  
Virtual Instrumentation ◽  
X Ray ◽  
Computer Based ◽  
X Ray Computed ◽  
Working Principle

X-ray computed tomography (called CT) scanner is a powerful and widely used medical imaging modality in the hospital. The CT machine is very expensive and it can produce dangerous radiation when a person operates the machine. This makes it difficult for biomedical engineers and radiographer students to learn its working principles. In order to overcome this problem, a computer based CT scanner trainer system has been developed. The system is implemented using National Instrument’s Laboratory Virtual Instrumentation Engineering Workbench (LabVIEW). At the beginning, it was started with the studying of existing CT scan machine. After gathering information, development process continued to develop generator component, x-ray tube subsystem, detector subsystem, imaging subsystem, and finally is reconstruction subsystem. The trainer system that has been developed is able to be used to train students on how to use CT scanner especially to get high quality images with lowest possible radiation. This will help biomedical engineers and radiographer students to have a better understanding of CT scanner in term of its working principle and to prevent radiation hazard during the learning process.

scholarly journals PET-CT: Radiological signs in Sarcoidosis-Lymphoma Syndrome

2020 ◽  
pp. 45-50
Author(s):  
Brunela Ronchi ◽  
Gustavo Peña ◽  
Muriel Henriquez
Keyword(s):  
Computed Tomography ◽  
Positron Emission Tomography ◽  
Clinical Case ◽  
Emission Tomography ◽  
Ct Scanner ◽  
X Ray ◽  
Positron Emission ◽  
Pet Ct ◽  
X Ray Computed ◽  
Complex Cases

Sarcoidosis-lymphoma syndrome is a clinical entity that can be diagnosed in different ways. Some of them are atypical. For these complex cases, positron emission tomography (PET) combined with an X-ray computed tomography (CT) scanner (PET-CT) is definitive for subsequent biopsy. A clinical case of our group is presented, which leads to the corresponding revision / update.

scholarly journals X-Ray Flow Visualization of a Circular Hydraulic Jump

2009 ◽  
Author(s):  
Megan R. DiVall ◽  
Theodore J. Heindel
Keyword(s):  
Computed Tomography ◽  
Film Thickness ◽  
Flow Visualization ◽  
Hydraulic Jump ◽  
Electrical Contact ◽  
Ct Images ◽  
3D Image ◽  
X Ray ◽  
Before And After ◽  
X Ray Computed

The circular hydraulic jump is a product of the impingement of a vertical, circular jet upon a smooth horizontal surface. Previous studies of this phenomenon have used methods such as electrical contact probes, photography, and lasers to measure various features. This study utilizes X-ray computed tomography (CT) to visualize the circular hydraulic jump; analysis is then completed on the reconstructed 3D image. Time-averaged data of the film thickness before and after the jump and the jump radius, as measured from the X-ray CT images, compare well with available literature. Potential imaging improvements with the current equipment have been identified, particularly with respect to measuring film thickness.

Sparsity driven deterministic sampling strategy for coded aperture X-ray Computed Tomography

2021 ◽  
Author(s):  
MUNNU SONKAR ◽  
Pradip Sasmal ◽  
Prasad Theeda ◽  
C S Sastry
Keyword(s):  
Computed Tomography ◽  
Sampling Strategy ◽  
Ct Images ◽  
Coded Aperture ◽  
Signal Recovery ◽  
X Ray ◽  
Deterministic Sampling ◽  
X Ray Computed ◽  
Unit Norm

Abstract The subsampling strategies in X-ray Computed Tomography (CT) gained importance due to their practical relevance. In this direction of research, also known as coded aperture X-ray computed tomography (CAXCT), both random and deterministic strategies were proposed in the literature. Of the techniques available, the ones based on Compressive Sensing (CS) recently gained more traction as CS based ideas efficiently exploit inherent duplication present in the system. The quality of the reconstructed CT images, nevertheless, depends on the sparse signal recovery properties (SRPs) of the sub-sampled Radon matrices. In the present work, we determine CAXCT deterministically in such a way that the corresponding sub-sampled Radon matrices remain close to the incoherent unit norm tight frames (IUNTFs) for better numerical behaviour. We show that this optimization, via Khatri-Rao product, leads to non-negative sparse approximation. While comparing and contrasting our method with its existing counterparts, we show that the proposed algorithm is computationally less involved. Finally, we demonstrate efficacy of the proposed deterministic sub-sampling strategy in recovering CT images both in noiseless and noisy cases.

scholarly journals Finite element modelling of UHPC under pulsating load using X-ray computed tomography based fiber distributions

2021 ◽  
Vol 55 (1) ◽  
Author(s):  
Nikolaos Mellios ◽  
Tyler Oesch ◽  
Panagiotis Spyridis
Keyword(s):  
Computed Tomography ◽  
Finite Element ◽  
High Performance ◽  
High Performance Concrete ◽  
Mechanical Tests ◽  
Ct Scanner ◽  
X Ray ◽  
Analysis And Design ◽  
Failure Patterns ◽  
X Ray Computed

AbstractThe benefits of including fibers in ultra-high performance concrete (UHPC) are attributed to their good bond with the matrix and, hence, an optimal utilization of their properties. At the same time, though, fiber reinforcement may contribute to anisotropy in the composite material and induce weak areas. The influence of the fibers’ orientation on the material properties is a matter of current scientific discourse and it is known to play a vital role in structural design. In the case studies presented herein, mechanical laboratory tests using pulsating load regimes on UHPC with a strength of more than 200 MPa were simulated by use of finite element models. The orientations of the fibers were measured for each test sample prior to failure using an X-ray computed tomography (CT) scanner, and these orientations are explicitly implemented into the model. The paper discusses the methodology of merging data retrieved by CT image processing and state-of-the-art FE simulation techniques Moreover, the CT scanning was carried out throughout the testing procedure, which further enables the comparison of the mechanical tests and the FE models in terms of damage propagation and failure patterns. The results indicate that the overall fiber configuration and behavior of the samples can be realistically modelled and validated by the proposed CT-FE coupling, which can enhance the structural analysis and design process of elements produced with steel fiber reinforced and UHPC materials.

A Radiologist's Art in CT Images

2013 ◽  
Vol 3 (4) ◽  
pp. 61-66
Author(s):  
Piyu Deo Mahant
Keyword(s):  
Computed Tomography ◽  
Medical Imaging ◽  
Human Body ◽  
Ct Images ◽  
Ct Scans ◽  
X Rays ◽  
Imaging Studies ◽  
X Ray ◽  
X Ray Computed

The story of medical imaging starts on 8 Nov, 1895, when Wilhelm Conrad Röntgen accidentally discovered X rays. Since then it has undergone great technological advancements helping physicians create images of the human body to reveal, diagnose, or examine disease (X-ray, n.d). CT scans combine the use of computers and x-rays to create virtual 'slices' of what is inside our body without cutting it open. Earlier many diseases could only be confirmed at autopsy. In 2010, more than 5 billion medical imaging studies were completed done worldwide (X-ray computed tomography, n.d).

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