Publikationen


Suche nach „[Jochen] [Hiller]“ hat 68 Publikationen gefunden
Suchergebnis als PDF
    DigitalNachhaltigFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Zeitschriftenartikel

    Gabriel Herl, Jochen Hiller, A. Maier

    Scanning trajectory optimisation using a quantitative Tuybased local quality estimation for robot-based X-ray computed tomography

    Nondestructive Testing and Evaluation, vol. (Published 21 June 2020), no. 6

    DOI: 10.1080/10589759.2020.1774579

    Abstract anzeigen

    Robotic CT systems allow complex scanning trajectories. This work presents a workflow to automatically calculate optimised scanning trajectories for robotic CT systems. In particular, as a local quality estimation, this work introduces a quantitative measure to quantify local reconstruction quality based on the Tuy conditions. The proposed method is tested in two summation experiments using an STL model of a motorcycle. In both experiments, a trajectory is calculated using a quantitative Tuy-based local quality estimation and the reconstruction result is then compared to reconstructions using conventional scanning trajectories. The comparison results indicate that the proposed approach automatically finds trajectories that enable 3D reconstructions with high image quality using much less projection data, which allows a significant reduction of scanning time.

    DigitalNachhaltigFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Zeitschriftenartikel

    A. Stock, Gabriel Herl, T. Sauer, Jochen Hiller

    Edge-preserving compression of CT scans using wavelets

    Insight - Non-Destructive Testing and Condition Monitoring (The British Institute of Non-Destructive Testing), vol. 62, no. 6, pp. 345-351

    DOI: 10.1784/insi.2020.62.6.345

    Abstract anzeigen

    This work addresses the subject of efficient storage of computed tomography (CT) data with an emphasis on the quality of surfaces. Industrial dimensional metrology often requires high measurement accuracy and it is shown that this is retained using wavelet-based compression methods. The applied techniques include a tensor product wavelet transform and soft wavelet shrinkage. In these tests, performed on real objects, dimensional CT measurements of compressed and uncompressed volumes were compared. The necessary storage space was reduced significantly with a negligible loss of accuracy. The storage space required for a multi-sphere phantom was decreased to 4.7% (from 638 MB to 30 MB), with an average deviation below 1 μm from the original volume.

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Zeitschriftenartikel

    F. Heilmeier, R. Koos, Peter Hornberger, Jochen Hiller, K. Weraneck, M. Jakobi, A. Koch, W. Volk

    Calibration of cast-in Fibre-Bragg-Gratings for internal strain measurements in cast aluminium by using neutron diffraction

    Measurement, vol. 163, no. 15 October 2020

    DOI: 10.1016/j.measurement.2020.107939

    Abstract anzeigen

    Fibre Bragg gratings (FBGs) are utilized to function as internal strain sensors during casting, solidification and cooling of two hypoeutectic Al alloys and technically pure Al. In situ neutron diffraction experiments were conducted simultaneously onsite the STRESS-SPEC instrument at the Research-Neutron Source (MLZ) in Garching. The experimental data correlated with structural finite element simulation and X-ray micro tomography (CT) elucidates the mechanisms of this measurement system. The presented work offers a new practical approach to measure in-situ strains during casting of Al alloys by using FBG-based sensors. The FBG strain results correlate with the Al(311) peak obtained by neutron diffraction which is furthermore used for calibration. The examination of interactions between fibres and surrounding cast Al by finite element simulation and CT of the cast specimens enables the application of the sensors for unequivocal strain measurements in castings as well as the characterization of alloys during solidification.

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Peter Landstorfer, Gabriel Herl, Jochen Hiller

    Investigation of Non-circular Scanning Trajectories in Robot-based Industrial X-ray Computed Tomography of Multi-material Objects

    16th International Conference on Informatics in Control, Automation and Robotics (ICINCO) [29-31 July, 2019; Prague, Czech Republic]

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Peter Landstorfer, Jochen Hiller, Matthias Herbst

    Investigation of positioning accuracy of industrial robots for robotic-based X-ray computed tomography

    iCT 2019 9th Conference on Industrial Computed Tomography (iCT) [13-15 February, 2019; Padua, Italy]

    Abstract anzeigen

    In this research work we investigated the accuracy of a standard industrial robot. We wanted to find out, how accurate an X-RayComputed Tomography (CT) scan can be performed when using such a robot as a manipulator. The accuracy was measuredusing a laser-interferometer. The measured deviations were used to run an X-Ray simulation via Fraunhofer EZRT’s ScorpiusX-Lab. Metrological analysis was performed as a measure for the quality of the simulated CT-scan. The metrological deviationsreflect the feasible accuracy of a CT-scan in a real CT-setup.

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Gabriel Herl, Jochen Hiller, T. Sauer

    Artifact reduction in X-ray computed tomography by multipositional data fusion using local image quality measures

    iCT 2019 9th Conference on Industrial Computed Tomography (iCT) [13-15 February, 2019; Padua, Italy]

    Abstract anzeigen

    Metal artifacts are still a major problem in X-ray industrial computed tomography. In order to reduce metal artifacts and increase the image quality of X-ray CT-scans, we suggest using projection data from multiple scans with differently positioned object orientations. We present two different approaches for multipositional CT, which are especially effective for multimaterial objects with high absorbing metal parts. On one hand, we reconstruct the different scans separatly, estimate the local quality of the resulting volumes and then fuse these volumes to an optimized volume. On the other hand, we introduce smART (shrinking merged Algebraic Reconstruction Technique) and merge sinograms of different scans, estimate the reliability of each projection pixel and then reconstruct the merged sinogram with an adapted SART reconstruction method. We demonstrate our approaches on simulations and on measurement data and are able to show a significant reduction of image artifacts qualitatively and quantitatively with the help of dimensional measurement results.

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Zeitschriftenartikel

    Gabriel Herl, Jochen Hiller, Kasperl, S. Maier, A.

    Reduktion von Metallartefakten durch multipositionale Datenfusion in der industriellen Röntgen-Computertomographie

    tm - Technisches Messen, vol. 87, no. 2

    DOI: 10.1515/teme-2019-0137

    Abstract anzeigen

    Metallartefakte stellen eine große Herausforderung für das Messen mit Röntgen-Computertomographie dar. Dieser Beitrag stellt die Methode der multipositionalen Datenfusion zur Reduktion von Metallartefakten vor. Dazu werden mehrere Scans desselben Objekts bei unterschiedlicher Objekt-positionierung durchgeführt, aufeinander registriert und zur Fusion gemeinsam unter Betrachtung eines lokalen Gütemaßes rekonstruiert. In praxisnahen Experimenten wird der Mehrwert der Methode gezeigt. Insbesondere wird dargestellt, wie mit wenig Aufwand und ohne Vorwissen Kunststoffstrukturen trotz starker Metallartefakte sichtbar gemacht werden können, womit das Verfahren ein Alleinstellungsmerkmal gegenüber den existierenden Metallartefaktreduktionsverfahren aufweist.

    DigitalNachhaltigFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Zeitschriftenartikel

    Peter Hornberger, A. Sigl, Jochen Hiller, S. Zabler

    Kleiner als ein Mikrometer: Entwicklung einer kompakten, hochauflösenden 3D-Röntgen-CT für die Materialanalyse

    VDI-Z (Sonderteil Additive Fertigung)

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Borges de Oliveira, F., M. Bartscher, U. Neuschaefer-Rube, R. Tutsch, Jochen Hiller

    Multi-Material Acceptance Testing for CT-Based Coordinate Measurement Systems

    Proceedings of the 12th International Conference on Measurement and Quality Control

    ISBN: 3030181766

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Zeitschriftenartikel

    Jochen Hiller, L. Reindl

    A computer simulation platform for the estimation of measurement uncertainties in dimensional X-ray computed tomography

    Measurement, vol. 45, no. 8, pp. 2166-2182

    DOI: 10.1016/j.measurement.2012.05.030

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    D. Schmid, J. Merz, Jochen Hiller

    New Method for Master Pattern Tool Correction Based on Computed Tomography Data and Intelligent Reverse Engineering

    iCT 2014 5th Conference on Industrial Computed Tomography (iCT) 2014

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Zeitschriftenartikel

    A. Gameros, L. Chiffre, H. Siller, Jochen Hiller, G. Genta

    A reverse engineering methodology for nickel alloy turbine blades with internal features

    CIRP Journal of Manufacturing Science and Technology, vol. 9, no. May, pp. 116-124

    DOI: 10.1016/j.cirpj.2014.12.001

    Abstract anzeigen

    The scope of this work is to present a reverse engineering (RE) methodology for freeform surfaces, based on a case study of a turbine blade made of Inconel, including the reconstruction of its internal cooling system. The methodology uses an optical scanner and X-ray computed tomography (CT) equipment. Traceability of the measurements was obtained through the use of a Modular Freeform Gage (MFG). An uncertainty budget is presented for both measuring technologies and results show that the RE methodology presented is promising when comparing uncertainty values against common industrial tolerances.

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Zeitschriftenartikel

    Peter Landstorfer, Jochen Hiller

    Präzision in drei Freiheitsgraden - Exakte Bauteilpositionierung bei CT-Messungen ohne zusätzliche Antriebe

    inspect, no. 2

    Abstract anzeigen

    Die präzise und reproduzierbare Ausrichtung von Messobjekten im CT ist eine wesentliche Voraussetzung für die Erzeugung vollständiger und genauer Datensätze. Mit einer universellen Positioniereinheit für industrielle Computertomographen (CT), die vollständig von den im Gerät vorhandenen Achsen angetrieben wird und dabei eine Ausrichtung von Messobjekten in drei Freiheitsgraden ermöglicht, wird dies in Zukunft einfacher zu realisieren sein.

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Simon Rettenberger, Peter Hornberger, A. Tissen, Jochen Hiller, S. Zabler

    Messtechnik und Materialprüfung an belasteten Bauteilen mit In-situ-Computertomographie

    Leitfaden zur industriellen Röntgentechnik, vol. 15

    ISBN: 978-3-8396-0913-2

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Peter Hornberger, Christian Aichinger, Jochen Hiller

    Dimensionelles Messen mit Computertomographie

    Leitfaden zur industriellen Röntgentechnik, vol. 15

    ISBN: 978-3-8396-0913-2

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Peter Landstorfer, Thomas Miller, Jochen Hiller

    Automatisierung von Mess- und Prüfprozessen mit Computertomographie

    Leitfaden zur industriellen Röntgentechnik, vol. 15

    ISBN: 978-3-8396-0913-2

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Mario Salzinger, Peter Hornberger, Jochen Hiller

    Analysis and comparison of the surface filtering characteristics of computed tomography and tactile measurements

    iCT 2016 6th Conference on Industrial Computed Tomography (iCT) 2016

    Abstract anzeigen

    Analysis and comparison of the surface filtering characteristics of computed tomography and tactile measurementsMario Salzinger, Peter Hornberger, Jochen HillerFraunhofer Application Center for Computed Tomography in Metrology CTMT, Deggendorf, Germany, e-mail: mario.salzinger@iis.fraunhofer.de, peter.hornberger@iis.fraunhofer.de, jochen.hiller@iis.fraunhofer.deAbstractThe use of industrial computed tomography for dimensional measurements is still met with considerable suspicion because of the numerous factors that influence the measurement uncertainty, which thus is hardly describable by a mathematical model. As a consequence, reference measurements with a tactile coordinate measuring machine (CMM) are usually performed. Image unsharpness when using computed tomography (CT) can be seen as low pass filter and therefore is one among many factors that influence the metrological performance of a CT system. However, it is also known that the geometry of the probe tip acts as a mechanical filter when using tactile CMMs. The studies in this work are performed with the help of a simple specimen which includes a number of surfaces of different waviness and roughness. Capturing the surfaces using both systems and comparing the results allows a deeper analysis and understanding of the filtering effects. The measurements are performed with probe balls of different diameters on a CMM. TheCT measurements are performed using various spatial resolution settings, resulting in different surface filtering characteristics. Additionally, surface measurements using a stylus instrument are performed. The comparison of these measurements shows that the CMM is more accurate when measuring form deviations of higher order. However, it also shows that the metrological performance, when measuring dimensional and geometrical measurands using the two systems, is comparable in many cases. Keywords: CMM, CT, metrology, roughness, surface, waviness

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Vortrag

    Mario Salzinger, Peter Hornberger, Jochen Hiller

    Analysis and comparison of the surface filtering characteristics of computed tomography and tactile measurements

    6th Conference on Industrial Computed Tomography (iCT 2016), Wels, Österreich

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Zeitschriftenartikel

    A. Detterbeck, M. Hofmeister, D. Haddad, D. Weber, M. Schmid, A. Hölzing, S. Zabler, E. Hofmann, K.-H. Hiller, P. Jakob, J. Engel, Jochen Hiller, U. Hirschenfelder

    Determination of the mesio-distal tooth width via 3D imaging techniques with and without ionizing radiation: CBCT, MSCT, and μCT versus MRI

    European Journal of Orthodontics, vol. 39, no. 3, pp. 310-319

    DOI: 10.1093/ejo/cjw047

    Abstract anzeigen

    Objective: The purpose of this study was to estimate the feasibility and accuracy of mesio-distal width measurements with magnetic resonance imaging (MRI) in comparison to conventional 3D imaging techniques [multi-slice CT (MSCT), cone-beam CT (CBCT), and µCT]. The measured values of the tooth widths were compared to each other to estimate the amount of radiation necessary to enable orthodontic diagnostics. Material and Methods: Two pig skulls were measured with MSCT, CBCT, µCT, and MRI. Three different judges were asked to determine the mesio-distal tooth width of 14 teeth in 2D tomographic images and in 3D segmented images via a virtual ruler in every imaging dataset. Results: Approximately 19% (27/140) of all test points in 2D tomographic slice images and 12% (17/140) of the test points in 3D segmented images showed a significant difference (P ≤ 0.05). The largest significant difference was 1.6mm (P < 0.001). There were fewer significant differences in the measurement of the tooth germs than in erupted teeth. Conclusions: Measurement of tooth width by MRI seems to be clinically equivalent to the conventional techniques (CBCT and MSCT). Tooth germs are better illustrated than erupted teeth on MRI. Three-dimensional segmented images offer only a slight advantage over 2D tomographic slice images. MRI, which avoids radiation, is particularly appealing in adolescents if these data can be corroborated in further studies.

    DigitalFraunhofer AWZ CTMTMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Jochen Hiller, Peter Hornberger, Mario Salzinger

    Bewertung technischer Oberflächen mit Röntgen-Computertomographie

    Leitfaden zur Inspektion und Charakterisierung von Oberflächen mit Bildverarbeitung, Stuttgart, vol. 16

    ISBN: 978-3-8396-1097-8