Frequency-based method to optimize the number of projections for industrial computed tomography
|
|
- Sherman Scott
- 5 years ago
- Views:
Transcription
1 More Info at Open Access Database Frequency-based method to optimize the number of projections for industrial computed tomography Andrea Buratti 1, Soufian Ben Achour 1, Christopher Isenberg 1, Robert Schmitt 1 1 Laboratory for Machine Tools and Production Engineering WZL of RWTH Aachen University, Steinbachstraße 19, Aachen, Germany; A.Buratti@wzl.rwth-aachen.de Abstract Industrial Computed Tomography (CT) has been regarded as a promising in the field of dimensional metrology due to its holistic approach to 3D coordinate measurements. Several CT scan parameters influence the measurement outcome and thus uncertainty of measurements. These quantities are the imaging parameters (tube voltage, tube current, prefilter, number of projections, etc.) and the manipulation parameters (source-object distance and workpiece orientation). The number of projections is an important factor to define the ability of the CT system to spatially resolve the geometrical features of a workpiece and defines the duration of a CT scan, as well. Low numbers of projections cause artifacts due to undersampling to occur which lower measurement accuracy, whereas acquiring too many projections involves high scanning times. CT users choose values for this parameter according to their experience. This often leads to high variability in measurement results, insufficient accuracy or unnecessarily long scanning time. Due to the complex transformations in the CT measurement chain, there is currently no analytical model that users can use to optimize the number of projections. In this study, we developed and evaluated a method to optimize the number of projections depending on the workpiece geometrical feature that has to be measured. Our focus is on dimensional metrology. The optimal value is the minimum number which ensures measurement accuracy fairly close to the theoretical maximum. First, the method considers a projection of the workpiece, which can be obtained by simulation or by a real scan. Then, the grey value distribution is considered and transformed into the Fourier domain. A radial filter which depends on the number of projections is applied to introduce the effect of undersampling on the projection. The filtered projection is then transformed back to the spatial domain and the contrast-to-noise ratio (CNR) is evaluated. The algorithm repeats this procedure by gradually decreasing the number of projections until the CNR decreases significantly. The obtained value represents the optimal number of projections. Finally, we applied this method to determine the optimal number of projections for the features of a test artifact and discussed the results. Keywords: Computed tomography, dimensional measurements, setup parameters, scan parameters, number of projections, prediction, geometrical feature 1 Introduction Industrial X-ray Computed Tomography (CT) is a multi-purpose non-destructive testing method. This technique allows reconstructing both the inner and the outer geometry of complex workpieces, without damaging or altering them. In the field of coordinate metrology, CT is a relatively new technology and represents an alternative to traditional coordinate measuring machines (CMM) [1]. Many factors influence the uncertainty of CT measurements. The user plays an important role by setting the CT scan parameters. These quantities are the imaging parameters (e.g. tube voltage, tube current, prefilter, number of projections) and the manipulation parameters (e.g. source-object distance and workpiece orientation). The number of projections is an important factor to define the ability of the CT system to spatially resolve the geometrical features of a workpiece and defines the duration of a CT scan, as well [2]. Low numbers of projections cause artifacts due to undersampling to occur which lower measurement accuracy, whereas acquiring too many projections involves high scanning times. CT users choose values for this parameter according to their experience. This often leads to high variability in measurement results, insufficient accuracy or unnecessarily long scanning time. Due to the complex transformations in the CT measurement chain, there is currently no analytical model that users can use to relate the number of projections to a given measurement task. 2 Method 2.1 Definition of the optimal number of projections First, we need to give a definition to the optimal number of projections. From a metrological point of view, the optimum is the number of projections that minimizes the influence of this parameter on the measurement uncertainty. We define it as the 1
2 metrological optimum. Generally speaking, the required number of projection depends on the maximum spatial frequency of the projection images and on the extension of the projected reconstruction volume [3]. For a given number of projections N, we define the angular sampling interval Δθ as follows: = (1) The maximum spatial frequency max can be expressed as follows [3]: = (2) where R represents the radius of the reconstruction volume projected onto the detector in the spatial domain. The volume is here considered as a bounding sphere, as shown in Figure 1. Figure 1: Cone beam and reconstruction sphere From an industrial perspective, CT users set scan parameters, including the number of projections, so that they can achieve the desired accuracy in the shortest tomographic time. In this sense, minimizing the contribution of the number of projections on the measurement uncertainty means a virtually infinite tomographic time. The industrial optimum is defined as the minimum number of projections which allows to achieve the desired accuracy in the shortest tomographic time. Intuitively, an increase of the number of projections involves an increase of the measurement accuracy. We can show this by assessing CT measurement error with respect to calibrated values and representing it as a function of the number of projections. Figure 2 shows this behavior for diameter measurements on a hole plate. Figure 2: CT measurement error with respect to calibrated measurements for diameter measurements on a hole plate. 2
3 In the left part of the graph, we can notice that the measurement error significantly decreases while N increases. Above a given value N*( projections), further increasing N does not determine a significant decrease of the measurement error, meaning that the improvement is negligible. Hence, we can define the technical optimum N* as the number of projections corresponding to the transition value from the region where the measurement error strongly depends on N to the one where its dependency is slight. In other words, the technical optimum minimizes the scanning time while ensuring a value for the uncertainty contribution of N fairly close to the minimum one. The three definitions for the optimum are summarized in Figure 3. Figure 3: Definition of optimum number of projections. 2.2 Estimation of the optimal number of projections for dimensional metrology The metrological optimum depends on the maximum spatial frequency of the object, which in general tends to infinite, since the bandwidth of the spectral support related to the projections is not strictly limited [4]. Similarly to what we pointed out for the technical optimum, we can identify a frequency value in the spectral support which we define as the maximum useful frequency. Frequencies above this one do not provide relevant information for reconstructing the object. Let us consider a set P1 of N < N* projections (being N* the technical optimum) and the corresponding reconstruction volume. Since N < N*, the reconstruction volume will be relevantly affected by undersampling artifacts. Of course, this effect cannot be seen on the projection images, since it appears only after reconstruction. Moreover, let P2 be a fictitious set of N* projections related to the same object, which give the same reconstruction volume as that of P1. These projection images will be instead affected by the effects of undersampling (Figure 4). Figure 4: Real and fictitious projection sets Projections of set P2 are not real, but we can conceive a method to apply the effect of undersampling on them and identify N*. In general, the maximum useful frequency varies in different projection images of the same object. We consider then the 3
4 projection with the maximum value among those available (e.g. obtained through simulation). In this way, we can consider one image and apply the effects of undersampling on it, so that it belongs to the set P2. By gradually decreasing the effects of undersampling, we can identify the minimum point at which image quality is approximately stable, and therefore compute N*. The algorithm to calculate N* consists of the following steps. First, we set an initial number of projection N = N 0, with N 0 certainly much higher than N*. In accordance with practical considerations, we set N 0 = Subsequently, we consider a projection image P(x,y) of the object. This can be obtained from a real scan or through simulation. We define a low-pass filter F in the frequency domain F( x, y). F is a radial filter with radial frequency w that can evaluated according to (1) and (2). = 4 (3) where R is the radius of the bounding sphere containing the workpiece in the spatial domain. The filter is then applied to the transformed projection image P. We therefore calculate the convolution l(x, y), which is a product in the frequency domain: We perform the inverse transformation of L and go back to the spatial domain., =,, (4),, (5) Now, we evaluate the image quality. In the field of dimensional metrology, we need to accurately detect the object surface and to reduce noise in order to get good measurement results. Hence, we choose the contrast-to-noise ratio (CNR) as an estimate for the image quality: = (6) where C is the image contrast and σ the standard deviation of the grey values. Since the chosen N = N 0 is higher than N*, we can consider the corresponding CNR as the maximum one: = (7) At this point, we set a new value for N by decreasing N 0. In general, at iteration i, the new number of projections Ni is given by: = (8) We repeat the procedure by evaluating the Fourier transform of the previously obtained filtered projection, by computing the new filter and applying it to the transformed projection. Finally, we perform the inverse trasformation of the convoluted projection and assess the new CNR. We iterate the algorithm as long as the CNR does not significantly decrease and its difference quotient with respect to N is much greater than zero. This condition at iteration i can be expressed as follows: < (9) where is a tolerance value which takes CNR random variability into account. The algorithm stops when (8) does not hold anymore. The corresponding number of projections represents the estimate for the technical optimum. Figure 5 and Figure 6 show a summary of the method. The algorithm was implemented into a MATLAB routine. 4
5 Figure 5: Steps of the algorithm to optimize the number of projections Figure 6: Scheme of the algorithm to optimize the number of projections 3 Description of the investigation In order to study the influence of undersampling on the measurement accuracy, we designed a test artifact. This workpiece is a disk made of POM (Figure 7a) and features several through holes with different diameters (Figure 7b). The holes were arranged along the disk radius to analyze the difference in the undersampling effect: we can expect that holes farther from the center will be more affected by these artifacts. 5
6 Figure 7: Test artefact, 3D model (a) and draft (b). To get reference measurements, the hole diameters were calibrated with a Zeiss Prismo tactile CMM. The diameters were measured at a height of 4 mm from the top surface. Subsequently, CT scans were performed with a Zeiss Metrotom Table 1 shows the used scan parameters. Material POM SOD [mm] 425 Tube Voltage [kv] 85 Tube Current [ma] 530 Integration time [ms] 1500 Table 1: Scan parameters for the test artifact. By applying the algorithm to optimize the number of projections, we get N* = 900. Figure 8 shows the behavior of the CNR related to the projections as a function of the number of projections. Figure 8: CNR as a function of the number of projections. 6
7 The effects of undersampling are shown in Figure 9. We can notice that for N = 900 there is no relevant undersampling artefact. Figure 9: Effects of undersampling on reconstruction for 10 (a), 100 (b), and 900 (c) projections For values of the number of projections between 25 and 1600, CT measurements were performed and all diameters were measured. Volume data were analysed using VG StudioMax software. The relative error with respect to CMM measurements is calculated as follows: = (10) where is the CT measurement of the diameter and is the corresponding calibrated measurement. Figure 10 shows the relative measurement error for diameter D16 (Figure 7b) as a function of the number of projections. We can notice that the measurement error is constant after 900 projections. This means that N = 900 is the technical optimum for feature D16. Figure 10: Relative measurement error of feature D16 as a function of the number of the number of projections. 4 Conclusions and future prospects In this study, we presented a method to optimize the number of projections for performing metrological tasks. The method identifies a technical optimum which guarantees high measurement accuracy while minimizing the tomographic time. It can be applied to both the whole object volume or to a region of interest. Experimental data are consistent with the predicted results, since the prediction of the technical optimum corresponds to the empirically determined one. Future work at the Laboratory for Machine Tools and Production Engineering (WZL) will deal with determining the industrial optimum as well as investigating the influence of different types of measurement task on the optimum. Acknowledgements The work has been funded by the European Union 7th Framework Programme under Grant Agreement The authors would like to thank Evelina Ametova (KU Leuven) for the fruitful discussions. 7
8 References [1] J.-P. Kruth, M.Bartscher, S. Carmignato, R. Schmitt, L. De Chiffre and A. Weckenmann, Computed Tomography for Dimensional Metrology, CIRP Annals, Vol 60, No 2, pp , [2] T. Buzug, Computed Tomography: From Photon Statistics to Modern Cone-Beam CT, Springer, 2008 [3] P. M. Joseph, R. A. Schulz, View sampling requirements in fan beam computed tomography, page 2, 1980 [4] J. Brokish and Y. Bresler, Sampling Requirements for Circular Cone Beam Tomography, Nuclear Science Symposium Conference Record, IEEE, vol.5, pp
Investigating the influence of workpiece placement on the uncertainty of measurements in industrial computed tomography
Investigating the influence of workpiece placement on the uncertainty of measurements in industrial computed tomography Natalia Grozmani 1, Andrea Buratti 1, Robert H. Schmitt 1 More info about this article:
More informationTHREE DIMENSIONAL INDUSTRIAL METROLOGY USING X-RAY COMPUTED TOMOGRAPHY ON COMPOSITE MATERIALS
THREE DIMENSIONAL INDUSTRIAL METROLOGY USING X-RAY COMPUTED TOMOGRAPHY ON COMPOSITE MATERIALS A. Campos a*, A. Zorrilla a, F. Lasagni a a Materials & Processes dept., Center for Advanced Aerospace Technologies
More informationMore Info at Open Access Database
More Info at Open Access Database www.ndt.net/?id=18750 Abstract Enhancing the Accuracy of Computed Tomography Measurements using Data Filtering Alessandro Stolfi a, Maarja-Helena Kallasse b, Lorenzo Carli
More informationOn the impact of probing form error on form measurement in Computed Tomography
On the impact of probing form error on form measurement in Computed Tomography Jan Lasson Andreasen 1, Filippo Montanari 2, Leonardo De Chiffre 2 More info about this article: http://www.ndt.net/?id=23729
More informationMulti-spectral (W, Mo, Cu, and Ag) XCT measurements
Multi-spectral (W, Mo, Cu, and Ag) XCT measurements Marko Katić 1, Damir Markučič 1, Gorana Baršić 1 Faculty of mechanical engineering and naval architecture, Ivana Lucica 5, Zagreb, Croatia, marko.katic@fsb.hr
More informationInvestigation of the kinematic system of a 450 kv CT scanner and its influence on dimensional CT metrology applications
Investigation of the kinematic system of a 450 kv CT scanner and its influence on dimensional CT metrology applications Frank Welkenhuyzen 1, Bart Boeckmans 1, Ye Tan 1,2, Kim Kiekens 1,2, Wim Dewulf 1,2,
More informationComparison of Probing Error in Dimensional Measurement by Means of 3D Computed Tomography with Circular and Helical Sampling
nd International Symposium on NDT in Aerospace - We..A. Comparison of Probing Error in Dimensional Measurement by Means of D Computed Tomography with Circular and Helical Sampling Jochen HILLER, Stefan
More informationSeparation of CT Nominal-Actual Comparisons for Compensation of Plastic Injection Molds
Separation of CT Nominal-Actual Comparisons for Compensation of Plastic Injection Molds Robert Schmitt 1, Christopher Isenberg 1 1 WZL of RWTH Aachen University, Steinbachstr. 19, 52074 Aachen, Germany,
More informationCreating a Multi-material Probing Error Test for the Acceptance Testing of Dimensional Computed Tomography Systems
Creating a Multi-material Probing Error Test for the Acceptance Testing of Dimensional Computed Tomography Systems More info about this article: http://www.ndt.net/?id=20848 Fabricio Borges de Oliveira
More informationParameter Dependent Thresholding for Dimensional X-ray Computed Tomography
International Symposium on Digital Industrial Radiology and Computed Tomography - Poster 12 Parameter Dependent Thresholding for Dimensional X-ray Computed Tomography Kim KIEKENS *, Ye TAN *, Jean-Pierre
More informationHIGH RESOLUTION COMPUTED TOMOGRAPHY FOR METROLOGY
HIGH RESOLUTION COMPUTED TOMOGRAPHY FOR METROLOGY David K. Lehmann 1, Kathleen Brockdorf 1 and Dirk Neuber 2 1 phoenix x-ray Systems + Services Inc. St. Petersburg, FL, USA 2 phoenix x-ray Systems + Services
More informationInvestigation on the influence of image quality in X-ray CT metrology
Investigation on the influence of image quality in X-ray CT metrology Pavel Müller 1, Jochen Hiller 1, Angela Cantatore 1, Markus Bartscher 2, Leonardo De Chiffre 1 1 Technical University of Denmark, Department
More informationEfficient 3D Crease Point Extraction from 2D Crease Pixels of Sinogram
Efficient 3D Crease Point Extraction from 2D Crease Pixels of Sinogram Ryo Jinnouchi 1, Yutaka Ohtake 1, Hiromasa Suzuki 1, Yukie Nagai 1 1 The University of Tokyo, Japan, e-mail: {jinnouchi, yu-ohtake,
More informationArion: a realistic projection simulator for optimizing laboratory and industrial micro-ct
Arion: a realistic projection simulator for optimizing laboratory and industrial micro-ct J. DHAENE* 1, E. PAUWELS 1, T. DE SCHRYVER 1, A. DE MUYNCK 1, M. DIERICK 1, L. VAN HOOREBEKE 1 1 UGCT Dept. Physics
More informationA cone-beam CT geometry correction method based on intentional misalignments to render the projection images correctable
A cone-beam CT geometry correction method based on intentional misalignments to render the projection images correctable Felix Meli, Benjamin A. Bircher, Sarah Blankenberger, Alain Küng, Rudolf Thalmann
More informationAn initial experimental study on the influence of beam hardening in X-ray CT for dimensional metrology
An initial experimental study on the influence of beam hardening in X-ray CT for dimensional metrology Joseph J. Lifton 1,2, Andrew A. Malcolm 2, John W. McBride 3 1 The University of Southampton, United
More informationRecognition and Measurement of Small Defects in ICT Testing
19 th World Conference on Non-Destructive Testing 2016 Recognition and Measurement of Small Defects in ICT Testing Guo ZHIMIN, Ni PEIJUN, Zhang WEIGUO, Qi ZICHENG Inner Mongolia Metallic Materials Research
More informationA universal method to optimise measurement uncertainty, time and cost for CMM scanning technology
universal method to optimise measurement uncertainty, time and cost for CMM scanning technology Prof. Dr.-Ing Robert Schmitt, Dipl.-Ing. Susanne Nisch Laboratory for Machine Tools and Production Engineering
More informationINVESTIGATION OF MEASURING STRATEGIES IN COMPUTED TOMOGRAPHY
NEWTECH 2011 NEW TECHNOLOGIES IN MANUFACTURING ISBN 978-80-214-4267-2 INVESTIGATION OF MEASURING STRATEGIES IN COMPUTED TOMOGRAPHY Pavel Müller, Jochen Hiller, Angela Cantatore, Leonardo De Chiffre Technical
More informationDUE to beam polychromacity in CT and the energy dependence
1 Empirical Water Precorrection for Cone-Beam Computed Tomography Katia Sourbelle, Marc Kachelrieß, Member, IEEE, and Willi A. Kalender Abstract We propose an algorithm to correct for the cupping artifact
More informationCharacterization of microshells experimented on Laser Megajoule using X-Ray tomography
Characterization of microshells experimented on Laser Megajoule using X-Ray tomography More info about this article: http://www.ndt.net/?id=20881 Alexandre Choux, Lise Barnouin, Ludovic Reverdy, Marc Theobald
More informationDevelopments in Dimensional Metrology in X-ray Computed Tomography at NPL
Developments in Dimensional Metrology in X-ray Computed Tomography at NPL Wenjuan Sun and Stephen Brown 10 th May 2016 1 Possible factors influencing XCT measurements Components Influencing variables Possible
More informationEvaluation strategies in CT scanning
Downloaded from orbit.dtu.dk on: Dec 20, 2017 Evaluation strategies in CT scanning Hiller, Jochen Publication date: 2012 Document Version Publisher's PDF, also known as Version of record Link back to DTU
More informationComputed Tomography & 3D Metrology Application of the VDI/VDE Directive 2630 and Optimization of the CT system
Computed Tomography & 3D Metrology Application of the VDI/VDE Directive 2630 and Optimization of the CT system ECNDT 2014 Prague October 6-10, 2014 Dr. Eberhard Neuser Dr. Alexander Suppes Imagination
More informationCT Systems and their standards
CT Systems and their standards Stephen Brown Engineering Measurement 11 th April 2012 Industrial X-ray computed tomography: The future of co-ordinate metrology? Burleigh Court, Loughborough University
More informationCT for Industrial Metrology Accuracy and Structural Resolution of CT Dimensional Measurements
CT for Industrial Metrology Accuracy and Structural Resolution of CT Dimensional Measurements Simone Carmignato 1, Anna Pierobon 2, Paola Rampazzo 1, Matteo Parisatto 3, Enrico Savio 2 1 University of
More informationAdapted acquisition trajectory and iterative reconstruction for few-views CT inspection
Adapted acquisition trajectory and iterative reconstruction for few-views CT inspection Caroline Vienne 1, Marius Costin 1 More info about this article: http://www.ndt.net/?id=21917 1 CEA, LIST, Département
More informationNovel evaluation method of low contrast resolution performance of dimensional X-ray CT
More Info at Open Access Database www.ndt.net/?id=18754 Novel evaluation method of low contrast resolution performance of dimensional X-ray CT Makoto Abe 1, Hiroyuki Fujimoto 1, Osamu Sato 1, Kazuya Matsuzaki
More informationAn Acquisition Geometry-Independent Calibration Tool for Industrial Computed Tomography
4th International Symposium on NDT in Aerospace 2012 - Tu.3.A.3 An Acquisition Geometry-Independent Calibration Tool for Industrial Computed Tomography Jonathan HESS *, Patrick KUEHNLEIN *, Steven OECKL
More informationCoordinate Measuring Machines with Computed Tomography
Always a Step Ahead with Quality Coordinate Measuring Machines with Computed Tomography Multisensor Coordinate Measuring Machines with Computed Tomography Computed Tomography in Coordinate Measuring Machines
More informationVoxel dataset noise reduction algorithm based on CMM reference measurements for geometrical tolerance analysis of prismatic test pieces
Voxel dataset noise reduction algorithm based on CMM reference measurements for geometrical tolerance analysis of prismatic test pieces More info about this article: http://www.ndt.net/?id=21929 Crhistian
More informationExperimental accuracy assessment of different measuring sensors on workpieces with varying properties
Experimental accuracy assessment of different measuring sensors on workpieces with varying properties Rauf Oezden 1,*, Metin Aclan 1 and Saliba Danho 2 1 Technical University of Cluj-Napoca, Ph.D. Stud.,
More informationAdvanced Reconstruction Techniques Applied to an On-Site CT System
2nd International Symposium on NDT in Aerospace 2010 - We.1.A.4 Advanced Reconstruction Techniques Applied to an On-Site CT System Jonathan HESS, Markus EBERHORN, Markus HOFMANN, Maik LUXA Fraunhofer Development
More informationASSESSMENT OF MEASUREMENT UNCERTAINTY CAUSED IN THE PREPARATION OF MEASUREMENTS USING COMPUTED TOMOGRAPHY
XIX IMEKO World Congress Fundamental and Applied Metrology September 6 11, 2009, Lisbon, Portugal ASSESSMENT OF MEASUREMENT UNCERTAINTY CAUSED IN THE PREPARATION OF MEASUREMENTS USING COMPUTED TOMOGRAPHY
More informationSelection of items for InteraqCT Comparison on Assemblies
More Info at Open Access Database www.ndt.net/?id=18776 Selection for InteraqCT Comparison on Assemblies Alessandro Stolfi, Leonardo De Chiffre Technical University of Denmark, Produktionstorvet Building
More informationHIGH-SPEED THEE-DIMENSIONAL TOMOGRAPHIC IMAGING OF FRAGMENTS AND PRECISE STATISTICS FROM AN AUTOMATED ANALYSIS
23 RD INTERNATIONAL SYMPOSIUM ON BALLISTICS TARRAGONA, SPAIN 16-20 APRIL 2007 HIGH-SPEED THEE-DIMENSIONAL TOMOGRAPHIC IMAGING OF FRAGMENTS AND PRECISE STATISTICS FROM AN AUTOMATED ANALYSIS P. Helberg 1,
More informationKNOWLEDGE-BASED OPTIMISATION OF THE TACTILE SCANNING PROCESS ON CMM
XIX IMEKO World Congress Fundamental and Applied Metrology September 6 11, 2009, Lisbon, Portugal KNOWLEDGE-BASED OPTIMISATION OF THE TACTILE SCANNING PROCESS ON CMM Prof. Dr.-Ing. Robert Schmitt, Dipl.-Ing.
More informationSimulation-based correction of systematic errors for CT measurements
Simulation-based correction of systematic errors for CT measurements Andreas Michael Müller 1, Florian Wohlgemuth 1, Tino Hausotte 1 1 Institute of Manufacturing Metrology, Friedrich-Alexander-Universität
More informationCreating a Multi-Material Length Measurement Error Test for the Acceptance Testing of Dimensional Computed Tomography Systems
Creating a Multi-Material Length Measurement Error Test for the Acceptance Testing of Dimensional Computed Tomography Systems More info about this article: http://www.ndt.net/?id=20847 Fabrício Borges
More informationReducing the influence of environmental scattering in industrial computed tomography by system optimisation and correction algorithms
11th European Conference on Non-Destructive Testing (ECNDT 2014), October 6-10, 2014, Prague, Czech Republic More Info at Open Access Database www.ndt.net/?id=16395 Reducing the influence of environmental
More informationQuality control phantoms and protocol for a tomography system
Quality control phantoms and protocol for a tomography system Lucía Franco 1 1 CT AIMEN, C/Relva 27A O Porriño Pontevedra, Spain, lfranco@aimen.es Abstract Tomography systems for non-destructive testing
More informationPerformance Evaluation of 3-Axis Scanner Automated For Industrial Gamma- Ray Computed Tomography
National Seminar & Exhibition on Non-Destructive Evaluation, NDE 2014, Pune, December 4-6, 2014 (NDE-India 2014) Vol.20 No.6 (June 2015) - The e-journal of Nondestructive Testing - ISSN 1435-4934 www.ndt.net/?id=17822
More informationGood practice guide for verification of area-scanning on-board metrology systems on machine tools
Good practice guide for verification of area-scanning on-board metrology systems on machine tools Vít Zelený, Ivana Linkeová, Jakub Sýkora, Pavel Skalník, Jaromír Hynek Czech Metrology Institute (CMI)
More informationSuitability of a new alignment correction method for industrial CT
Suitability of a new alignment correction method for industrial CT Matthias Elter 1, Nicole Maass 1, Peter Koch 2 1 Siemens AG, Healthcare Sector, Erlangen, Germany, e-mail: matthias.elter@siemens.com,
More informationCase Studies in the Use of Computed Tomography for Non-Destructive Testing, Inspection and Measurement
SINCE2013 Singapore International NDT Conference & Exhibition 2013, 19-20 July 2013 Case Studies in the Use of Computed Tomography for Non-Destructive Testing, Inspection and Measurement Andrew A. MALCOLM,
More informationNon-Stationary CT Image Noise Spectrum Analysis
Non-Stationary CT Image Noise Spectrum Analysis Michael Balda, Björn J. Heismann,, Joachim Hornegger Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen Siemens Healthcare, Erlangen michael.balda@informatik.uni-erlangen.de
More informationComparison of Reconstruction Methods for Computed Tomography with Industrial Robots using Automatic Object Position Recognition
19 th World Conference on Non-Destructive Testing 2016 Comparison of Reconstruction Methods for Computed Tomography with Industrial Robots using Automatic Object Position Recognition Philipp KLEIN 1, Frank
More informationRegistration concepts for the just-in-time artefact correction by means of virtual computed tomography
DIR 2007 - International Symposium on Digital industrial Radiology and Computed Tomography, June 25-27, 2007, Lyon, France Registration concepts for the just-in-time artefact correction by means of virtual
More informationScienceDirect. Comparison of Different Method of Measurement Geometry using CMM, Optical Scanner and Computed Tomography 3D
Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 69 (2014 ) 255 262 24th DAAAM International Symposium on Intelligent Manufacturing and Automation, 2013 Comparison of Different
More informationINFLUENCE OF GEOMETRICAL MAGNIFICATION ON COMPUTED TOMOGRAPHY DIMENSIONAL MEASUREMENTS
DOI: 10.2507/27th.daaam.proceedings.090 INFLUENCE OF GEOMETRICAL MAGNIFICATION ON COMPUTED TOMOGRAPHY DIMENSIONAL MEASUREMENTS Amalija Horvatić Novak, Biserka Runje, Danijel Butković This Publication has
More informationWieblinger Weg 92a, Heidelberg, Germany, Phone: , Fax: ;
HOW INDUSTRIAL COMPUTER TOMOGRAPHY ACCELERATES PRODUCT DEVELOPMENT IN THE LIGHT METAL CASTING AND INJECTION MOULDING INDUSTRY. Christof REINHART 1, Christoph POLIWODA 1, Thomas GÜNTHER 1 1 Volume Graphics
More informationComparision of contact and contactless measuring methods for form evaluation
Available online at www.sciencedirect.com Procedia Engineering 48 (2012 ) 273 279 MMaMS 2012 Comparision of contact and contactless measuring methods for form evaluation Peter Ka uch a, Miroslav Dovica
More informationDEVELOPMENT OF CONE BEAM TOMOGRAPHIC RECONSTRUCTION SOFTWARE MODULE
Rajesh et al. : Proceedings of the National Seminar & Exhibition on Non-Destructive Evaluation DEVELOPMENT OF CONE BEAM TOMOGRAPHIC RECONSTRUCTION SOFTWARE MODULE Rajesh V Acharya, Umesh Kumar, Gursharan
More informationCT Measurement Realization Process: The Need for Advanced Correction Methods
CT Measurement Realization Process: The Need for Advanced Correction Methods Crhistian R Baldo 1, Thiago L Fernandes 2, Gustavo D Donatelli 2, Gergely Szikszay-Molnar 3, Kostadin Doytchinov 3 1 Federal
More informationUncertainty Evaluation of Pore Analysis for Additively Manufactured Parts using Cross Sections
Uncertainty Evaluation of Pore Analysis for Additively Manufactured Parts using Cross Sections More info about this article: http://www.ndt.net/?id=23659 Abstract Leonard Schild 1, Manuel Fülling 1, Benjamin
More informationUse of reference objects for correction of measuring errors in X-ray computed tomography
Downloaded from orbit.dtu.dk on: Nov 19, 2018 Use of reference objects for correction of measuring errors in X-ray computed tomography Müller, Pavel Publication date: 2010 Document Version Publisher's
More informationThickness Measurement of Metal Plate Using CT Projection Images and Nominal Shape
Thickness Measurement of Metal Plate Using CT Projection Images and Nominal Shape Tasuku Ito 1, Yutaka Ohtake 1, Yukie Nagai 2, Hiromasa Suzuki 1 More info about this article: http://www.ndt.net/?id=23662
More informationComparison of Scatter Correction Methods for CBCT. Author(s): Suri, Roland E.; Virshup, Gary; Kaissl, Wolfgang; Zurkirchen, Luis
Research Collection Working Paper Comparison of Scatter Correction Methods for CBCT Author(s): Suri, Roland E.; Virshup, Gary; Kaissl, Wolfgang; Zurkirchen, Luis Publication Date: 2010 Permanent Link:
More informationComparison between 3D Digital and Optical Microscopes for the Surface Measurement using Image Processing Techniques
Comparison between 3D Digital and Optical Microscopes for the Surface Measurement using Image Processing Techniques Ismail Bogrekci, Pinar Demircioglu, Adnan Menderes University, TR; M. Numan Durakbasa,
More informationUltrasonic Multi-Skip Tomography for Pipe Inspection
18 th World Conference on Non destructive Testing, 16-2 April 212, Durban, South Africa Ultrasonic Multi-Skip Tomography for Pipe Inspection Arno VOLKER 1, Rik VOS 1 Alan HUNTER 1 1 TNO, Stieltjesweg 1,
More informationThe new generation of industrial computed tomography. The Desktop CT exact S
The new generation of industrial computed tomography The Desktop CT S Volume scanning technology Innovation with a family tradition Founded in 1968, the family-owned, WEN- ZEL Metrology Group is one of
More informationDigital Laminography and Computed Tomography with 600 kv for Aerospace Applications
4th International Symposium on NDT in Aerospace 2012 - Tu.3.A.1 Digital Laminography and Computed Tomography with 600 kv for Aerospace Applications Malte KURFISS 1, Gerd STRECKENBACH 2 1 YXLON International
More informationDiscrete Estimation of Data Completeness for 3D Scan Trajectories with Detector Offset
Discrete Estimation of Data Completeness for 3D Scan Trajectories with Detector Offset Andreas Maier 1, Patrick Kugler 2, Günter Lauritsch 2, Joachim Hornegger 1 1 Pattern Recognition Lab and SAOT Erlangen,
More informationTraceable 3D X-Ray Measurements ZEISS METROTOM
20 Traceable 3D X-Ray Measurements With a computer tomograph, you can successfully perform measuring and inspection jobs yourself with only one X-ray scan. The standard acceptance test, the precision engineering
More informationX-ray Industrial Computed Laminography (ICL) Simulation Study of Planar Objects: Optimization of Laminographic Angle
More info about this article: http://www.ndt.net/?id=21086 X-ray Industrial Computed Laminography (ICL) Simulation Study of Planar Objects: Optimization of Laminographic Angle Lakshminarayana Yenumula
More informationThe PolyCT Increasing the sample throughput using multiple rotation axes
The PolyCT Increasing the sample throughput using multiple rotation axes More info about this article: http://www.ndt.net/?id=21946 1 Dr. Nicolas Thiemeyer, Johannes Leisner 2, Michael Salamon 2, Carina
More informationCentral Slice Theorem
Central Slice Theorem Incident X-rays y f(x,y) R x r x Detected p(, x ) The thick line is described by xcos +ysin =R Properties of Fourier Transform F [ f ( x a)] F [ f ( x)] e j 2 a Spatial Domain Spatial
More informationCOMPARISON OF ERROR MAPPING TECHNIQUES FOR COORDINATE MEASURING MACHINES USING THE PLATE METHOD AND LASER TRACER TECHNIQUE
I IMEKO World Congress Fundamental and Applied Metrology September 6, 9, Lisbon, Portugal COMPARISON OF ERROR MAPPING TECHNIQUES FOR COORDINATE MEASURING MACHINES USING THE PLATE METHOD AND LASER TRACER
More informationA geometry measurement system for a dimensional cone-beam CT
A geometry measurement system for a dimensional cone-beam CT More info about this article: http://www.ndt.net/?id=21904 Benjamin A. Bircher, Felix Meli, Alain Küng, Rudolf Thalmann Federal Institute of
More informationIntroduction to XCT and its growth
Introduction to XCT and its growth Professor Richard Leach FInstP FIoN Engineering Measurement Division Measurement Network Meeting, Loughborough April 2012 X-ray computed tomography History X-ray were
More informationBeam Attenuation Grid Based Scatter Correction Algorithm for. Cone Beam Volume CT
11th European Conference on Non-Destructive Testing (ECNDT 2014), October 6-10, 2014, Prague, Czech Republic Beam Attenuation Grid Based Scatter Correction Algorithm for More Info at Open Access Database
More informationAM INSPECTION / NDT: IS XCT THE SOLUTION?
AM INSPECTION / NDT: IS XCT THE SOLUTION? Dr. Nick Brierley Principal Research Engineer Metrology & NDT Group nick.brierley@the-mtc.org April 2018 OUTLINE Challenges of AM post-build inspection XCT for
More informationIndustrial Computer Tomography for Dimensional Metrology: Overview of Influence Factors and Improvement Strategies
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Industrial Computer Tomography for Dimensional Metrology: Overview of Influence Factors and
More informationHow beam hardening influences the dimensional geometry in X-ray computed tomography
How beam hardening influences the dimensional geometry in X-ray computed tomography More info about this article: http://www.ndt.net/?id=20809 Hannah Corcoran 1, 2, Stephen Brown 2, Stuart Robson 1, Robert
More informationOptimization of scanner parameters for dual energy micro-ct
Optimization of scanner parameters for dual energy micro-ct E. PAUWELS* 1, J. DHAENE 1, A. DE MUYNCK 1 E., M. DIERICK 1, L. VAN HOOREBEKE 1 1 UGCT Dept. Physics and Astronomy, Ghent University, Proeftuinstraat
More informationMULTI-PURPOSE 3D COMPUTED TOMOGRAPHY SYSTEM
MULTI-PURPOSE 3D COMPUTED TOMOGRAPHY SYSTEM M. Simon, C. Sauerwein, I. Tiseanu, S. Burdairon Hans Wälischmiller GmbH Klingleweg 8, D-88709 Meersburg, Germany e-mail: ms@hwm.com ABSTRACT A new flexible
More informationJapan Foundry Society, Inc. Application of Recent X-ray CT Technology to Investment Casting field. Kouichi Inagaki ICC / IHI Corporation
Japan Foundry Society, Inc. Application of Recent X-ray CT Technology to Investment Casting field Kouichi Inagaki ICC / IHI Corporation 13 th WORLD CONFERENCE ON INVESTMENT CASTING Paper: T3 Copyright
More informationAvailable online at ScienceDirect
Available online at www.sciencedirect.com ScienceDirect Procedia CIRP 13 ( 2014 ) 43 48 2 nd CIRP 2nd CIRP Conference on Surface Integrity (CSI) Computed Tomography as a Tool for Examining Surface Integrity
More informationLimited view X-ray CT for dimensional analysis
Limited view X-ray CT for dimensional analysis G. A. JONES ( GLENN.JONES@IMPERIAL.AC.UK ) P. HUTHWAITE ( P.HUTHWAITE@IMPERIAL.AC.UK ) NON-DESTRUCTIVE EVALUATION GROUP 1 Outline of talk Industrial X-ray
More informationTranslational Computed Tomography: A New Data Acquisition Scheme
2nd International Symposium on NDT in Aerospace 2010 - We.1.A.3 Translational Computed Tomography: A New Data Acquisition Scheme Theobald FUCHS 1, Tobias SCHÖN 2, Randolf HANKE 3 1 Fraunhofer Development
More informationMULTIPLE-SENSOR INTEGRATION FOR EFFICIENT REVERSE ENGINEERING OF GEOMETRY
Proceedings of the 11 th International Conference on Manufacturing Research (ICMR2013) MULTIPLE-SENSOR INTEGRATION FOR EFFICIENT REVERSE ENGINEERING OF GEOMETRY Feng Li, Andrew Longstaff, Simon Fletcher,
More informationInternational Symposium on Digital Industrial Radiology and Computed Tomography - Mo.2.2
International Symposium on Digital Industrial Radiology and Computed Tomography - Mo.2.2 Accuracy Evaluation and Exploration of Measurement Uncertainty for Exact Helical Cone Beam Reconstruction Using
More informationComputed tomography (Item No.: P )
Computed tomography (Item No.: P2550100) Curricular Relevance Area of Expertise: Biology Education Level: University Topic: Modern Imaging Methods Subtopic: X-ray Imaging Experiment: Computed tomography
More informationCIVA CT, an advanced simulation platform for NDT
More Info at Open Access Database www.ndt.net/?id=18774 CIVA CT, an advanced simulation platform for NDT Marius Costin 1, David Tisseur 1, Caroline Vienne 1, Ronan Guillamet 1, Hussein Banjak 1, Navnina
More informationEMRP JRP IND62 TIM: Use of on-board metrology systems for area-scanning on machine tools
EMRP JRP IND62 TIM: Use of on-board metrology systems for area-scanning on machine tools Author: Co-authors: doc. Ing. Vít Zelený, CSc. doc. Ing. Ivana Linkeová, Ph.D. Ing. Jakub Sýkora Pavel Skalník Jaromír
More informationProjection and Reconstruction-Based Noise Filtering Methods in Cone Beam CT
Projection and Reconstruction-Based Noise Filtering Methods in Cone Beam CT Benedikt Lorch 1, Martin Berger 1,2, Joachim Hornegger 1,2, Andreas Maier 1,2 1 Pattern Recognition Lab, FAU Erlangen-Nürnberg
More informationarxiv: v1 [physics.ins-det] 21 Aug 2009
NOTE arxiv:0908.3209v1 [physics.ins-det] 21 Aug 2009 Practical Way to Measure Large-Scale 2D Surfaces Using Repositioning on Coordinate-Measuring Machines Sergey Kosarevsky Saint-Petersburg Institute of
More informationDigital Volume Correlation for Materials Characterization
19 th World Conference on Non-Destructive Testing 2016 Digital Volume Correlation for Materials Characterization Enrico QUINTANA, Phillip REU, Edward JIMENEZ, Kyle THOMPSON, Sharlotte KRAMER Sandia National
More informationTEP Hounsfield units. Related topics Attenuation coefficient, Hounsfield units
Hounsfield units TEP Related topics Attenuation coefficient, Hounsfield units Principle Depending on the type of CT scanner and the settings, the result of a CT scan of the same material can be different
More informationDesign and performance characteristics of a Cone Beam CT system for Leksell Gamma Knife Icon
Design and performance characteristics of a Cone Beam CT system for Leksell Gamma Knife Icon WHITE PAPER Introduction Introducing an image guidance system based on Cone Beam CT (CBCT) and a mask immobilization
More informationReconstruction Methods for Coplanar Translational Laminography Applications
Reconstruction Methods for Coplanar Translational Laminography Applications U. EWERT, K.-U. THIESSENHUSEN, A. DERESCH, C. BELLON, S. HOHENDORF, S. KOLKOORI, N. WROBEL, B. REDMER, M. TSCHAIKNER, BAM, Berlin
More informationA Procedure for accuracy Investigation of Terrestrial Laser Scanners
A Procedure for accuracy Investigation of Terrestrial Laser Scanners Sinisa Delcev, Marko Pejic, Jelena Gucevic, Vukan Ogizovic, Serbia, Faculty of Civil Engineering University of Belgrade, Belgrade Keywords:
More informationTOLERANCE ANALYSIS OF THIN-WALL CFRP STRUCTURAL ELEMENTS USING TOMOGRAPHIC IMAGING
Proceedings of the 6th International Conference on Mechanics and Materials in Design, Editors: J.F. Silva Gomes & S.A. Meguid, P.Delgada/Azores, 26-30 July 2015 PAPER REF: 5495 TOLERANCE ANALYSIS OF THIN-WALL
More informationEvaluation of Spectrum Mismatching using Spectrum Binning Approach for Statistical Polychromatic Reconstruction in CT
Evaluation of Spectrum Mismatching using Spectrum Binning Approach for Statistical Polychromatic Reconstruction in CT Qiao Yang 1,4, Meng Wu 2, Andreas Maier 1,3,4, Joachim Hornegger 1,3,4, Rebecca Fahrig
More informationCT vs. VolumeScope: image quality and dose comparison
CT vs. VolumeScope: image quality and dose comparison V.N. Vasiliev *a, A.F. Gamaliy **b, M.Yu. Zaytsev b, K.V. Zaytseva ***b a Russian Sci. Center of Roentgenology & Radiology, 86, Profsoyuznaya, Moscow,
More informationExperimental investigation of new multi-material gap reference standard for testing computed tomography systems
More info about this article: http://www.ndt.net/?id=20837 Experimental investigation of new multi-material gap reference standard for testing computed tomography systems Petr Hermanek 1, Fabrício Borges
More informationSpiral ASSR Std p = 1.0. Spiral EPBP Std. 256 slices (0/300) Kachelrieß et al., Med. Phys. 31(6): , 2004
Spiral ASSR Std p = 1.0 Spiral EPBP Std p = 1.0 Kachelrieß et al., Med. Phys. 31(6): 1623-1641, 2004 256 slices (0/300) Advantages of Cone-Beam Spiral CT Image quality nearly independent of pitch Increase
More informationGeneralized Filtered Backprojection for Digital Breast Tomosynthesis Reconstruction
Generalized Filtered Backprojection for Digital Breast Tomosynthesis Reconstruction Klaus Erhard a, Michael Grass a, Sebastian Hitziger b, Armin Iske b and Tim Nielsen a a Philips Research Europe Hamburg,
More informationAdvanced Computed Tomography System for the Inspection of Large Aluminium Car Bodies
ECNDT 2006 - Th.3.4.2 Advanced Computed Tomography System for the Inspection of Large Aluminium Car Bodies M. SIMON, I. TISEANU, C. SAUERWEIN Hans WÄLISCHMILLER, Meersburg, Germany M. SINDEL, M. BRODMANN,
More informationEvaluation of 3D fiber orientation analysis based on x-ray computed tomography data
Evaluation of 3D fiber orientation analysis based on x-ray computed tomography data Thomas Riedel Robert Bosch GmbH, Corporate Research and Development, Department Plastic Engineering (CR/APP3), Alte Bundesstrasse
More information