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Suche nach „[Hiller] [Jochen]“ hat 60 Publikationen gefunden
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    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

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

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

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

    2019

    ISBN: 3030181766

    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

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

    Edge preserving compression of CT scans using wavelets

    SHM-NDT 2018 International Symposium on Structural Health Monitoring and Nondestructive Testing 4-5 Oct 2018, Saarbrücken – Germany

    2018

    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 we show that this is retained using wavelet-based compression methods. The applied techniques include a tensor product wavelet transform and soft wavelet shrinkage. In our tests on real objects, we compared dimensional CT measurements of compressed and uncompressed volumes. We were able to reduce the necessary storage space significantly with a minimal loss of accuracy. For a multi sphere phantom, we decreased the storage space to 4.7% (from 638 MB to 30 MB) with an average deviation below 1 µm from the original volume.

    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

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

    Metal artifact reduction by fusion of CT scans from different positions using the unfiltered backprojection

    iCT 2018 8th Conference on Industrial Computed Tomography (iCT) 2018, 6-9 Feb, Wels, Austria

    2018

    Abstract anzeigen

    Metal objects or metal parts in an object are still a major problem of X-ray computed tomography (CT) because of so called metal artifacts. We propose a new method – a multipositional data fusion – for automatically fusing multiple CT volumes from different positions to reduce these metal artifacts. After scanning a specimen several times at different positions and reconstruction of every scan (e.g. by the filtered backprojection), we also perform an unfiltered backprojection. Based on the assumption that metal artifacts occur the most wherever X-rays are attenuated a lot, the unfiltered backprojection is used to autonomously estimate the likelihood of metal artifacts in every voxel of every scan. The different volumes are registered and then fused by weighted sum preferring the voxels with low values in the unfiltered backprojection results. In our tests on real objects, our method fully automatically created optimized volumes with significantly less metal artifacts. The multipositional data fusion was compared to the commercially multi spectra fusion of Werth Messtechnik GmbH and outperformed it in one of the use cases.

    DigitalMaschinenbau und Mechatronik

    Zeitschriftenartikel

    Mario Salzinger, Jochen Hiller, Thomas Fischer, Daniel Heinz

    Quantitative Untersuchung zur Reduzierung der Messzeit in der dimensionellen Computertomographie

    Bavarian Journal of Applied Sciences, vol. 3, no. 1, pp. 282-296

    2017

    DOI: 10.25929/jy3v-pm72

    Abstract anzeigen

    Einer der häufig genannten Nachteile für Computertomographie-(CT-)Anwender in der industriellen Praxis ist der Zeitfaktor. Für einen messtechnisch auswertbaren CT-Scan ist das System in den meisten Fällen mindestens 30 Minuten lang ausgelastet, je nach Prüfobjekt und Genauigkeitsanforderungen oft auch deutlich länger. Ziel dieser Untersuchung ist es, mit derzeitig möglichen Methoden herauszufinden, wie die Scanzeiten verringert werden können und wie sich diese Reduzierung auf die Qualität der Messung bezüglich Messgenauigkeit und Wiederholgenauigkeit auswirkt. Nach Auswahl und taktiler Referenzmessung eines Prüfkörpers werden mit dem 360° Stop&Go-Verfahren sowie mit zwei weiteren Scanstrategien, der 180° CT und der FlyBy-CT, Messdaten erzeugt. Es folgt ein Vergleich der Messergebnisse und der Messzeiten. Bei der 180°-Messung wird das Objekt intermittierend um die Hälfte rotiert, wohingegen beim FlyBy-Modus eine kontinuierliche Objektbewegung ohne Abbremsung erfolgt. Beide Messverfahren haben sich für diverse Anwendungsszenarien bewährt. Die größte Messzeitreduzierung ist beim Einsatz des FlyBy-Modus zu erwarten. Im Vergleich dazu bietet der 180°-Modus ebenfalls Vorteile, auch wenn die erwartete Scanzeit gegenüber dem FlyBy-Modus länger ist. Mit diesem lässt sich trotz der Möglichkeit zur Bildmittelung Scanzeit einsparen, gegenüber dem herkömmlichen 360°-Scanverfahren lässt sich aber zudem bei gleichbleibender Zeit eine erhöhte Rauschreduzierung erzielen. One of the biggest disadvantages operators complain about in the field of industrial computed tomography is the time factor. CT scans for measuring purposes will usually take at least 30 minutes, yet often noticeably longer, depending on the specimen and accuracy requirements. The purpose of this research is to determine how scan times can be reduced by applying the currently available methods and to assess in which way this reduction influences measurement quality with regards to measurement accuracy and repeatability. After choosing a test specimen and performing tactile measurements to determine the nominal values, measurement data is generated by using the 360° Stop&Go procedure, the 180° CT and the FlyBy-CT. Then the measurement results and durations are compared with each other. Measurements using the 180° procedure are performed by intermittently rotating the object by 180 degrees, whereas the FlyBy mode involves a continuous object movement without deceleration. Both CT modes are well proven in various applications. Out of all three methods, the FlyBy mode has the greatest potential for reducing overall scan times. In comparison, the 180° mode also has its advantages, although the expected scan times are longer compared to the FlyBy mode. This CT mode offers the opportunity to reduce scan times despite the option of image averaging. In addition, compared to the conventional 360° scan procedures, it is possible to achieve a higher level of noise reduction within a constant time.

    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Christian Aichinger, Jochen Hiller, Peter Hornberger

    Dimensionelles Messen mit Computertomographie

    Handbuch zur industriellen Bildverarbeitung. Qualitätssicherung in der Praxis

    2017

    ISBN: 978-3-8396-1226-2

    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Jochen Hiller, Thomas Miller, Peter Hornberger

    Dimensional Metrology for Industrial Computed Tomography

    Handbook of X-ray Imaging - Physics and Technology, Boca Raton, FL, USA

    2017

    ISBN: 9781498741521

    DigitalMaschinenbau und Mechatronik

    Zeitschriftenartikel

    F. Bittner, Jochen Hiller, Simon Rettenberger, H.-J. Endres

    Blick in belastete Composite-Bauteile

    Konstruktion (Zeitschrift für Produktentwicklung und Ingenieur-Werkstoffe), no. 5

    2017

    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Gabriel Herl, Jochen Hiller, Simon Rettenberger

    Fusion mehrerer Computertomographie-Aufnahmen zur Verbesserung der Bildqualität

    Forschungsbericht 2016/2017 der Technischen Hochschule Deggendorf

    2017

    DigitalMaschinenbau und Mechatronik

    Zeitschriftenartikel

    N. Sawczyn, D. Imkamp, Jochen Hiller, E. Uhlmann

    Untersuchungen zur Messunsicherheit und Wirtschaftlichkeit dimensioneller Computertomographie-Messungen an ausgewählten Beispielen

    tm - Technisches Messen, vol. 84, no. 5, pp. 336-347

    2017

    Abstract anzeigen

    Die industrielle Computertomographie (CT) wird zunehmend für die zerstörungsfreie Prüfung von Bauteilen als Instrument der fertigungsbegleitenden Qualitätssicherung eingesetzt. Ein Vorteil gegenüber taktilen oder optischen Messverfahren ist insbesondere die Möglichkeit, sowohl außen- als auch innenliegende Geometriemerkmale zerstörungsfrei zu erfassen. In diesem Beitrag werden anhand ausgewählter Bauteile Möglichkeiten zur Steigerung der Wirtschaftlichkeit von CT-Messungen durch gleichzeitige tomographische Erfassung mehrerer Bauteile im Messvolumen untersucht und die Messunsicherheit für die einzelnen Aufnahmeszenarien experimentell ermittelt.

    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Mario Salzinger, Jochen Hiller, Peter Hornberger

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

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

    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

    DigitalMaschinenbau und Mechatronik

    Zeitschriftenartikel

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

    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

    2016

    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.

    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Mario Salzinger, Jochen Hiller, Peter Hornberger

    Bewertung technischer Oberflächen mit Röntgen-Computertomographie

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

    2016

    ISBN: 978-3-8396-1097-8

    DigitalMaschinenbau und Mechatronik

    Zeitschriftenartikel

    Jochen Hiller, Peter Hornberger

    Measurement accuracy in X-ray computed tomography metrology: Toward a systematic analysis of interference effects in tomographic imaging

    Precision Engineering, vol. 45, no. July, pp. 18-32

    2016

    DOI: 10.1016/j.precisioneng.2015.12.003

    Abstract anzeigen

    In this paper an investigation of interference effects leading to limitations of metrological performance of X-ray computed tomography (CT) used as a coordinate measuring technique is presented. Using reconstruction data, image quality metrics, and calculations of artifact formation, a deeper understanding and explanation of the physical and technical limitations of CT used in dimensional metrology is given. This is demonstrated in a case study using a simple hollow cylinder made of steel as a test object and calibration measurements from a tactile coordinate measuring machine (CMM). Two different threshold determination strategies for surface computation are applied. Within the study it is also shown that CT image properties, threshold determination strategies, and systematic and random measurement errors must have a definite correlation. As a conclusion it is recommended to focus more strongly on the correlation of local CT image quality and data evaluation operations in order to reduce systematic errors in surface computation and to increase repeatability of dimensional CT measurements.

    DigitalMaschinenbau und Mechatronik

    Zeitschriftenartikel

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

    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

    2015

    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.

    DigitalMaschinenbau und Mechatronik

    Zeitschriftenartikel

    Jochen Hiller, Peter Landstorfer

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

    inspect, no. 2

    2015

    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.

    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

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

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

    Leitfaden zur industriellen Röntgentechnik, vol. 15

    2015

    ISBN: 978-3-8396-0913-2

    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Christian Aichinger, Jochen Hiller, Peter Hornberger

    Dimensionelles Messen mit Computertomographie

    Leitfaden zur industriellen Röntgentechnik, vol. 15

    2015

    ISBN: 978-3-8396-0913-2

    DigitalMaschinenbau und Mechatronik

    Beitrag (Sammelband oder Tagungsband)

    Jochen Hiller, Peter Landstorfer, Thomas Miller

    Automatisierung von Mess- und Prüfprozessen mit Computertomographie

    Leitfaden zur industriellen Röntgentechnik, vol. 15

    2015

    ISBN: 978-3-8396-0913-2

    DigitalMaschinenbau und Mechatronik

    Zeitschriftenartikel

    E. Kraus, S. Zabler, Jochen Hiller, B. Baudrit, S. Horlemann, M. Bastian, A. Tissen

    In-situ-Prüfungen von Kunststoff-Klebeverbindungen mit Computertomographie

    KGK Rubber Point - Kautschuk Gummi Kunststoffe, no. 4

    2015

    Abstract anzeigen

    Das mechanische Verhalten von geklebten PEEK-Verbindungen wurde unter Belastung mittels Computertomographie in-situ untersucht. Hierbei wurden für eine Zugscher-Probe die Dehnungsverteilungen in der gesamten Klebeverbindung sowie in der Klebeebene lokal bei einem mehraxialen Zustand analysiert.

    DigitalMaschinenbau und Mechatronik

    Zeitschriftenartikel

    P. Müller, L. Chiffre, H. Hansen, Jochen Hiller, J. Andreasen, Y. Dai

    Quantitative analysis of scaling error compensation methods in dimensional X-ray computed tomography

    CIRP Journal of Manufacturing Science and Technology, vol. 10, no. August, pp. 68-76

    2015

    DOI: 10.1016/j.cirpj.2015.04.004

    Abstract anzeigen

    X-ray Computed Tomography (CT) has become an important technology for quality control of industrial components. As with other technologies, e.g., tactile coordinate measurements or optical measurements, CT is influenced by numerous quantities which may have negative impact on the accuracy and repeatability of dimensional and geometrical measurements. The aim of this paper is to discuss different methods for the correction of scaling errors and to quantify their influence on dimensional measurements. Scaling errors occur first and foremost in CT systems with no built-in compensation of positioning errors of the manipulator system (magnification axis). This article also introduces a new compensation method for scaling errors using a database of reference scaling factors and discusses its advantages and disadvantages. In total, three methods for the correction of scaling errors – using the CT ball plate, using calibrated features measured by CMM and using a database of reference values – are presented and applied within a case study. The investigation was performed on a dose engine component of an insulin pen, for which several dimensional measurands were defined. The component has a complex geometry and is made of brass, which makes its measurements with CT challenging. It is shown that each scaling error correction method results in different deviations between CT measurements and reference measurements from a CMM. Measurement uncertainties were estimated for each method, taking into consideration the contributions related to the applied correction method. The newly suggested approach using the database appeared to work well, indicating, that if the properties of a CT system under investigation are monitored using a reference object (ball bar in our case), a correction factor based on individual selected magnification factors can be applied for scaling error correction of any object, and thus no additional scanning of a reference object is needed.