<?xml version="1.0" encoding="utf-8"?>
<export-example>
  <doc>
    <id>52579</id>
    <completedYear/>
    <publishedYear>2021</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>lecture</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">2D-Photothermal super-resolution with sparse matrix stacking</title>
    <abstract language="eng">Thermographic super resolution techniques allow the spatial resolution of defects/inhomogeneities below the classical limit, which is governed by the diffusion properties of thermal wave propagation. In this work, we re-port on the extension of this approach towards a full frame 2D super resolution technique. The approach is based on a repeated spatially structured heating using high power lasers. In a second post-processing step, several measurements are coherently combined using mathematical optimization and taking advantage of the (joint) sparsity of the defects in the sample.</abstract>
    <enrichment key="eventName">Sensor and Measurement Science International Conference SMSI 2021</enrichment>
    <enrichment key="eventPlace">Online meeting</enrichment>
    <enrichment key="eventStart">03.05.2021</enrichment>
    <enrichment key="eventEnd">06.05.2020</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">true</enrichment>
    <enrichment key="InvitedTalks">0</enrichment>
    <author>Julien Lecompagnon</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Super-resolution</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>NDT</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Inspection</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Image resolution</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Präsentation</collection>
  </doc>
  <doc>
    <id>52589</id>
    <completedYear/>
    <publishedYear>2021</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>183</pageFirst>
    <pageLast>184</pageLast>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume>SMSI 2021 - Sensors and Instrumentation</volume>
    <type>conferenceobject</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">2D-Photothermal Super Resolution with Sparse Matrix Stacking</title>
    <abstract language="eng">Thermographic super resolution techniques allow the spatial resolution of defects/inhomogeneities below the classical limit, which is governed by the diffusion properties of thermal wave propagation. In this work, we report on the extension of this approach towards a full frame 2D super resolution technique. The approach is based on a repeated spatially structured heating using high power lasers. In a second post-processing step, several measurements are coherently combined using mathematical optimization and taking advantage of the (joint) sparsity of the defects in the sample</abstract>
    <parentTitle language="eng">SMSI 2021 Proceedings</parentTitle>
    <identifier type="isbn">978-3-9819376-4-0</identifier>
    <identifier type="doi">10.5162/SMSI2021/C2.2</identifier>
    <enrichment key="eventName">Sensor and Measurement Science International Conference SMSI 2021</enrichment>
    <enrichment key="eventPlace">Online meeting</enrichment>
    <enrichment key="eventStart">03.05.2021</enrichment>
    <enrichment key="eventEnd">06.05.2020</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">true</enrichment>
    <author>Julien Lecompagnon</author>
    <author>Samim Ahmadi</author>
    <author>Philipp Daniel Hirsch</author>
    <author>Mathias Ziegler</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Super-resolution</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>NDT</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Inspection</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Image resolution</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Graue Literatur</collection>
  </doc>
  <doc>
    <id>52639</id>
    <completedYear/>
    <publishedYear>2021</publishedYear>
    <thesisYearAccepted/>
    <language>deu</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>poster</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="deu">Thermografische Super Resolution mit 2D-strukturierter Erwärmung</title>
    <abstract language="deu">Thermografische Super Resolution ermöglicht die Auflösung von Defekten/Inhomogenitäten unterhalb des klassischen Limits, welches durch die Diffusionseigenschaften der thermischen Wellenausbreitung bestimmt wird. Basierend auf einer Kombination aus der Anwendung spezieller Abtaststrategien und einer anschließenden numerischen Optimierungsschritt bei der Datenauswertung hat sich die thermografische Super Resolution bereits bei der Detektion von 1D-Defekten gegenüber den Standard-Thermografieverfahren als überlegen erwiesen. In unserer Arbeit erweitern wir die Möglichkeiten der Methode zur effizienten Detektion und Auflösung von Defektquerschnitten mit einer vollständig 2D-strukturierten Erwärmung.&#13;
Der experimentelle Ansatz basiert auf einer wiederholten räumlich strukturierten Erwärmung durch einen Hochleistungslaser. In einem zweiten Nachbearbeitungsschritt werden mehrere kohärente Messungen mittels mathematischer Optimierung und unter Ausnutzung der (Joint-) Sparsity der Defekte innerhalb des Prüfkörpers kombiniert. Als Ergebnis kann eine 2D-sparse Defekt-/ Inhomogenitätskarte erhalten werden. Da die Kombination von räumlich strukturierter Erwärmung und anschließender numerischer Kombination mehrerer kohärenter Messungen nicht nur die Auflösung verbessert, sondern auch die Messkomplexität drastisch erhöht, werden verschiedene Scanstrategien untersucht. Abschließend werden die erhaltenen Ergebnisse mit denen konventioneller thermografischer Prüfverfahren verglichen.</abstract>
    <identifier type="url">https://jahrestagung.dgzfp.de/Programm#P45</identifier>
    <identifier type="urn">urn:nbn:de:kobv:b43-526396</identifier>
    <enrichment key="eventName">DGZfP-Jahrestagung 2021</enrichment>
    <enrichment key="eventPlace">Online meeting</enrichment>
    <enrichment key="eventStart">10.05.2021</enrichment>
    <enrichment key="eventEnd">11.05.2021</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">true</enrichment>
    <licence>Creative Commons - CC BY-ND - Namensnennung - Keine Bearbeitungen 4.0 International</licence>
    <author>Julien Lecompagnon</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Super-resolution</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>NDT</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Inspection</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Image resolution</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="fulltextaccess" number="">Datei für die Öffentlichkeit verfügbar ("Open Access")</collection>
    <collection role="literaturgattung" number="">Präsentation</collection>
    <collection role="unnumberedseries" number="">BAM Präsentationen</collection>
    <thesisPublisher>Bundesanstalt für Materialforschung und -prüfung (BAM)</thesisPublisher>
    <file>https://opus4.kobv.de/opus4-bam/files/52639/DGZFPJT2021_Poster_Le_merged.pdf</file>
  </doc>
  <doc>
    <id>53757</id>
    <completedYear/>
    <publishedYear>2021</publishedYear>
    <thesisYearAccepted/>
    <language>deu</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>lecture</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="deu">Thermische Kontraste - der Blick hinter die Fassade</title>
    <abstract language="deu">Die Thermografie beruht auf der bildlichen Darstellung von Temperaturunterschieden oder auch thermischen Kontrasten an der Oberfläche eines Untersuchungsobjektes. Diese bilden sich nur her-aus, wenn sich das Untersuchungsobjekt gerade erwärmt oder abkühlt. Der Beitrag erklärt mittels eines stark vereinfachten Modells die Entstehung solcher Kontraste als dynamischen Effekt ver-schiedener Abkühlgeschwindigkeiten. Neben Laborergebnissen werden beispielhaft einige Ergeb-nisse von einem mittelalterlichen Baudenkmal präsentiert, um das Verständnis für die thermografi-sche Inspektion von Fassaden zu vertiefen.</abstract>
    <enrichment key="eventName">14. Konservierungswissenschaftliches Kolloquium Berlin Brandenburg</enrichment>
    <enrichment key="eventPlace">Berlin, Germany</enrichment>
    <enrichment key="eventStart">12.11.2021</enrichment>
    <enrichment key="eventEnd">12.11.2021</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">true</enrichment>
    <enrichment key="InvitedTalks">0</enrichment>
    <author>Rainer Krankenhagen</author>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>Aktive Thermografie</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>Bauthermografie</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>Ablösungen</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>Metallanker</value>
    </subject>
    <collection role="ddc" number="624">Ingenieurbau</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Infrastruktur</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Präsentation</collection>
  </doc>
  <doc>
    <id>53745</id>
    <completedYear/>
    <publishedYear>2021</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>124</pageFirst>
    <pageLast>131</pageLast>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume>11914</volume>
    <type>conferenceobject</type>
    <publisherName>International Society for Optics and Photonics. SPIE</publisherName>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>1</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Investigations on photothermal super resolution reconstruction using 2D-structured illumination patterns</title>
    <abstract language="eng">Active thermography as a nondestructive testing modality suffers greatly from the limitations imposed by the diffusive nature of heat conduction in solids. As a rule of thumb, the detection and resolution of internal defects/inhomogeneities is limited to a defect depth to defect size ratio greater than or equal to one. Earlier, we demonstrated that this classical limit can be overcome for 1D and 2D defect geometries by using photothermal laser-scanning super resolution. In this work we report a new experimental approach using 2D spatially structured illumination patterns in conjunction with compressed sensing and computational imaging methods to significantly decrease the experimental complexity and make the method viable for investigating larger regions of interest.</abstract>
    <parentTitle language="eng">SPIE Future Sensing Technologies 2021</parentTitle>
    <identifier type="doi">10.1117/12.2603838</identifier>
    <enrichment key="eventName">Future Sensing Technologies Conference 2021</enrichment>
    <enrichment key="eventPlace">Online meeting</enrichment>
    <enrichment key="eventStart">15.11.2021</enrichment>
    <enrichment key="eventEnd">19.11.2021</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="date_peer_review">13.06.2022</enrichment>
    <author>Julien Lecompagnon</author>
    <author>Samim Ahmadi</author>
    <author>Philipp Daniel Hirsch</author>
    <author>C. Rupprecht</author>
    <author>Mathias Ziegler</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Super resolution</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>NDT</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Inspection</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Image resolution</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Graue Literatur</collection>
  </doc>
  <doc>
    <id>53747</id>
    <completedYear/>
    <publishedYear>2021</publishedYear>
    <thesisYearAccepted/>
    <language>deu</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>lecture</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="deu">Investigations on photothermal super resolution reconstruction using 2D-structured illumination patterns</title>
    <abstract language="deu">Active thermography as a nondestructive testing modality suffers greatly from the limitations imposed by the diffusive nature of heat conduction in solids. As a rule of thumb, the detection and resolution of internal defects/inhomogeneities is limited to a defect depth to defect size ratio greater than or equal to one. Earlier, we demonstrated that this classical limit can be overcome for 1D and 2D defect geometries by using photothermal laser-scanning super resolution. In this work we report a new experimental approach using 2D spatially structured illumination patterns in conjunction with compressed sensing and computational imaging methods to significantly decrease the experimental complexity and make the method viable for investigating larger regions of interest.</abstract>
    <identifier type="url">https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11914/2603838/Investigations-on-photothermal-super-resolution-reconstruction-using-2D-structured-illumination/10.1117/12.2603838.full</identifier>
    <enrichment key="eventName">Future Sensing Technologies Conference 2021</enrichment>
    <enrichment key="eventPlace">Online meeting</enrichment>
    <enrichment key="eventStart">15.11.2021</enrichment>
    <enrichment key="eventEnd">19.11.2021</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">true</enrichment>
    <enrichment key="InvitedTalks">0</enrichment>
    <author>Julien Lecompagnon</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Super resolution</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>NDT</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Inspection</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Image resolution</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Präsentation</collection>
  </doc>
  <doc>
    <id>55384</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>poster</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Photothermal characterization of polyester composites loaded with parallelly arranged graphite rods</title>
    <abstract language="eng">One of the biggest challenges in the measurement of thermal properties is to measure inhomogeneous materials This work focuses on measuring the thermal properties of cylindrical polyester resin composite materials loaded with graphite rods oriented in the direction of the resin thickness, varying the graphite concentrations starting from zero to 8 75 of volumetric fraction and changing the distribution of graphite rods inside the polyester matrix.</abstract>
    <enrichment key="eventName">International Conference in Photoacoustics and Photothermal Phenomena (ICPPP21)</enrichment>
    <enrichment key="eventPlace">Bled, Slovenia</enrichment>
    <enrichment key="eventStart">19.06.2022</enrichment>
    <enrichment key="eventEnd">24.06.2022</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <author>Nelson Wilbur Pech May</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Heat diffusion</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Heterogeneous materials</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Präsentation</collection>
  </doc>
  <doc>
    <id>55386</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>lecture</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Automatic inspection of surface breaking cracks using laser scanning thermography</title>
    <abstract language="eng">In this work, we report on a method for automatic inspection of components using laser scanning thermography, in which the relative motion is performed by a robot to fully inspect complex test objects such as turbine blades. We demonstrate our evaluation algorithms with the aim of automatically detecting surface defects on calibrated specimens. We show the influence of the excitation laser, which can be varied in terms of spot geometry, wavelength, and scan scheme. Additionally, we show some advantages, versatility, and current challenges of using a programmed robot for non-destructive evaluation in thermography.</abstract>
    <enrichment key="eventName">International Conference in Photoacoustics and Photothermal Phenomena (ICPPP21)</enrichment>
    <enrichment key="eventPlace">Bled, Slovenia</enrichment>
    <enrichment key="eventStart">19.06.2022</enrichment>
    <enrichment key="eventEnd">24.06.2022</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="InvitedTalks">0</enrichment>
    <author>Nelson Wilbur Pech May</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Flying line thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Surface breaking defects</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Canny approach</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Präsentation</collection>
  </doc>
  <doc>
    <id>54909</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>1</pageFirst>
    <pageLast>10</pageLast>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume>12109</volume>
    <type>conferenceobject</type>
    <publisherName>SPIE</publisherName>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>1</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Thermographic testing using 2D pseudo-random illumination and photothermal super resolution reconstruction</title>
    <abstract language="eng">Due to the diffusive nature of heat propagation in solids, the detection and resolution of internal defects with active thermography based non-destructive testing is commonly limited to a defect-depth-to-defect-size ratio greater than or equal to one. In the more recent past, we have already demonstrated that this limitation can be overcome by using a spatially modulated illumination source and photothermal super resolution-based reconstruction. Furthermore, by relying on compressed sensing and computational imaging methods we were able to significantly reduce the experimental complexity to make the method viable for investigating larger regions of interest. In this work we share our progress on improving the defect/inhomogeneity characterization using fully 2D spatially structured illumination patterns instead of scanning with a single laser spot. The experimental approach is based on the repeated blind pseudo-random illumination using modern projector technology and a high-power laser. In the subsequent post-processing, several measurements are then combined by taking advantage of the joint sparsity of the defects within the sample applying 2D-photothermal super resolution reconstruction. Here, enhanced nonlinear convex optimization techniques are utilized for solving the underlying ill-determined inverse problem for typical simple defect geometries. As a result, a higher resolution defect/inhomogeneity map can be obtained at a fraction of the measurement time previously needed.</abstract>
    <parentTitle language="eng">Proceedings of SPIE</parentTitle>
    <identifier type="issn">0277-786X</identifier>
    <identifier type="doi">10.1117/12.2618562</identifier>
    <enrichment key="eventName">Thermosense: Thermal Infrared Applications XLIV</enrichment>
    <enrichment key="eventPlace">Orlando, Florida, USA</enrichment>
    <enrichment key="eventStart">05.04.2022</enrichment>
    <enrichment key="eventEnd">07.04.2022</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="date_peer_review">08.09.2022</enrichment>
    <author>Julien Lecompagnon</author>
    <author>Philipp Daniel Hirsch</author>
    <author>C. Rupprecht</author>
    <author>Mathias Ziegler</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Super resolution</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>NDT</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Material testing</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Internal defects</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>DMD</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>DLP</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Graue Literatur</collection>
  </doc>
  <doc>
    <id>54378</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>1</pageFirst>
    <pageLast>20</pageLast>
    <pageNumber/>
    <edition/>
    <issue>1</issue>
    <volume>41</volume>
    <type>article</type>
    <publisherName>Springer</publisherName>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>1</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Determination of thermal parameters of concrete by active thermographic measurements</title>
    <abstract language="eng">The knowledge of the thermal parameters of a particular concrete is essential for thermal design of a building, but also could help to identify and assess the state of a concrete structure. Active thermography has the potential to be applied onsite and to provide a fast investigation of thermal properties. In this work, three different concrete samples were investigated by active thermography in reflection and in transmission setup. It was found that this method yields the same results without direct contact as the Transient Plane Source (TPS) method as an established inspection tool.</abstract>
    <parentTitle language="eng">Journal of Nondestructive Evaluation</parentTitle>
    <identifier type="issn">0195-9298</identifier>
    <identifier type="issn">1573-4862</identifier>
    <identifier type="doi">10.1007/s10921-022-00861-6</identifier>
    <identifier type="urn">urn:nbn:de:kobv:b43-543781</identifier>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="date_peer_review">21.03.2022</enrichment>
    <licence>Creative Commons - CC BY - Namensnennung 4.0 International</licence>
    <author>Rainer Krankenhagen</author>
    <author>Stefan Zirker</author>
    <author>Florian Joniertz</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Concrete</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Effusivity</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermal diffusivity</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Photothermal</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Hot disc method</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Parker method</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Onsite inspection</value>
    </subject>
    <collection role="ddc" number="624">Ingenieurbau</collection>
    <collection role="institutes" number="">2 Prozess- und Anlagensicherheit</collection>
    <collection role="institutes" number="">2.1 Sicherheit von Energieträgern</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Infrastruktur</collection>
    <collection role="literaturgattung" number="">Verlagsliteratur</collection>
    <collection role="fulltextaccess" number="">Datei für die Öffentlichkeit verfügbar ("Open Access")</collection>
    <collection role="unnumberedseries" number="">Wissenschaftliche Artikel der BAM</collection>
    <thesisPublisher>Bundesanstalt für Materialforschung und -prüfung (BAM)</thesisPublisher>
    <file>https://opus4.kobv.de/opus4-bam/files/54378/Krankenhagen_et_al-2022-Journal_of_Nondestructive_Evaluation.pdf</file>
  </doc>
  <doc>
    <id>54667</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>lecture</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Thermographic testing using 2D pseudo-random illumination and photothermal super resolution reconstruction</title>
    <abstract language="eng">Due to the diffusive nature of heat propagation in solids, the detection and resolution of internal defects with active thermography based non-destructive testing is commonly limited to a defect-depth-to-defect-size ratio greater than or equal to one. In the more recent past, we have already demonstrated that this limitation can be overcome by using a spatially modulated illumination source and photothermal super resolution-based reconstruction. Furthermore, by relying on compressed sensing and computational imaging methods we were able to significantly reduce the experimental complexity to make the method viable for investigating larger regions of interest. In this work we share our progress on improving the defect/inhomogeneity characterization using fully 2D spatially structured illumination patterns instead of scanning with a single laser spot. The experimental approach is based on the repeated blind pseudo-random illumination using modern projector technology and a high-power laser. In the subsequent post-processing, several measurements are then combined by taking advantage of the joint sparsity of the defects within the sample applying 2D-photothermal super resolution reconstruction. Here, enhanced nonlinear convex optimization techniques are utilized for solving the underlying ill-determined inverse problem for typical simple defect geometries. As a result, a higher resolution defect/inhomogeneity map can be obtained at a fraction of the measurement time previously needed.</abstract>
    <enrichment key="eventName">Thermosense: Thermal Infrared Applications XLIV</enrichment>
    <enrichment key="eventPlace">Orlando, FL, USA</enrichment>
    <enrichment key="eventStart">05.04.2022</enrichment>
    <enrichment key="eventEnd">07.04.2022</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">true</enrichment>
    <enrichment key="InvitedTalks">0</enrichment>
    <author>Julien Lecompagnon</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Super resolution</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>NDT</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Material testing</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Internal defects</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>DMD</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>DLP</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Präsentation</collection>
  </doc>
  <doc>
    <id>54678</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>1</pageFirst>
    <pageLast>9</pageLast>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume>71</volume>
    <type>article</type>
    <publisherName>IEEE</publisherName>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>1</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Photothermal-SR-Net: A customized deep unfolding neural network for photothermal super resolution imaging</title>
    <abstract language="eng">This article presents deep unfolding neural networks to handle inverse problems in photothermal radiometry enabling super-resolution (SR) imaging. The photothermal SR approach is a well-known technique to overcome the spatial resolution limitation in photothermal imaging by extracting high-frequency spatial components based on the deconvolution with the thermal point spread function (PSF). However, stable deconvolution can only be achieved by using the sparse structure of defect patterns, which often requires tedious, handcrafted tuning of hyperparameters and results in computationally intensive algorithms. On this account, this article proposes Photothermal-SR-Net, which performs deconvolution by deep unfolding considering the underlying physics. Since defects appear sparsely in materials, our approach includes trained block-sparsity thresholding in each convolutional layer. This enables to super-resolve 2-D thermal images for nondestructive testing (NDT) with a substantially improved convergence rate compared to classic approaches. The performance of the proposed approach is evaluated on various deep unfolding and thresholding approaches. Furthermore, we explored how to increase the reconstruction quality and the computational performance. Thereby, it was found that the computing time for creating high-resolution images could be significantly reduced without decreasing the reconstruction quality by using pixel binning as a preprocessing step.</abstract>
    <parentTitle language="eng">IEEE Transactions on Instrumentation and Measurement</parentTitle>
    <identifier type="issn">1557-9662</identifier>
    <identifier type="doi">10.1109/tim.2022.3154803</identifier>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="date_peer_review">25.04.2022</enrichment>
    <enrichment key="RelatedIdentifier">https://nbn-resolving.org/urn:nbn:de:kobv:b43-525371</enrichment>
    <author>Samim Ahmadi</author>
    <author>L. Kästner</author>
    <author>Jan Christian Hauffen</author>
    <author>P. Jung</author>
    <author>Mathias Ziegler</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Deep unfolding</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Defect reconstruction</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Elastic net</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Inverse problems</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Iterative shrinkage thresholding</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Neural network</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Nondestructive testing (NDT)</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Photothermal imaging</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Super resolution (SR)</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="literaturgattung" number="">Verlagsliteratur</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
  </doc>
  <doc>
    <id>54943</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>1</pageFirst>
    <pageLast>8</pageLast>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume>12109</volume>
    <type>conferenceobject</type>
    <publisherName>Society of Photo-Optical Instrumentation Engineers (SPIE)</publisherName>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>1</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Weather-dependent passive thermography of unheated wind turbine blades</title>
    <abstract language="eng">Up to now, the inspection of wind turbines with industrial climbers has been considered ”state of the art”. However, ever-larger wind turbines and advancing digitization make modern and automated inspection methods indispensable. Passive thermography can serve as such a digital and atomized method while it is well known for its applications in the inspection of buildings or electrical circuits. However, its application relies on thermal gradients in the inspected object such that a temperature contrast exists between damaged and sound areas. This also holds for unheated structures like rotor blades of wind turbines which show no intrinsic temperature gradient and can hardly be heated. Under certain weather conditions with sufficient solar loading and diurnal temperature variations, passive thermography is suitable for the in-service inspection of rotor blades. However, for a reliable use of passive thermography on ”thermal passive” components, the incorporation of these environmental conditions in the planning and evaluation of thermal inspections is crucial. Additionally, the complex inner structure of wind turbine blades in comparison to other objects and buildings require a specific method referencing the individual rotor blades to each other. This allows the distinction between the thermal response of design-specific structural features and damages or irregularities between the three blades. We show thermal signatures of damage in rotor blades and contrast them with structural characteristics by comparing the three blades. In addition to measurements in industrial environments, laboratory measurements are shown and compared to simulations. The long-term goal is to simulate the influence of different weather parameters and thus gain a better understanding of measurements in the field. The results shown here can be seen as one step towards industrial application.</abstract>
    <parentTitle language="eng">Proceedings, Thermosense: Thermal Infrared Applications XLIV</parentTitle>
    <identifier type="doi">10.1117/12.2618740</identifier>
    <enrichment key="eventName">SPIE Defense + Commercial Sensing</enrichment>
    <enrichment key="eventPlace">Orlando, Florida, USA</enrichment>
    <enrichment key="eventStart">03.04.2022</enrichment>
    <enrichment key="eventEnd">07.04.2022</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="RelatedIdentifier">https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/54944</enrichment>
    <enrichment key="date_peer_review">08.09.2022</enrichment>
    <author>Michael Stamm</author>
    <author>Rainer Krankenhagen</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Passive thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Wind energy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>FEM simulations</value>
    </subject>
    <collection role="ddc" number="621">Angewandte Physik</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Energie</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Graue Literatur</collection>
  </doc>
  <doc>
    <id>54944</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>lecture</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Weather-dependent passive thermography of unheated wind turbine blades</title>
    <abstract language="eng">Up to now, the inspection of wind turbines with industrial climbers has been considered ”state of the art”. However, ever-larger wind turbines and advancing digitization make modern and automated inspection methods indispensable. Passive thermography can serve as such a digital and atomized method while it is well known for its applications in the inspection of buildings or electrical circuits. However, its application relies on thermal gradients in the inspected object such that a temperature contrast exists between damaged and sound areas. This also holds for unheated structures like rotor blades of wind turbines which show no intrinsic temperature gradient and can hardly be heated. Under certain weather conditions with sufficient solar loading and diurnal temperature variations, passive thermography is suitable for the in-service inspection of rotor blades. However, for a reliable use of passive thermography on ”thermal passive” components, the incorporation of these environmental conditions in the planning and evaluation of thermal inspections is crucial. Additionally, the complex inner structure of wind turbine blades in comparison to other objects and buildings require a specific method referencing the individual rotor blades to each other. This allows the distinction between the thermal response of design-specific structural features and damages or irregularities between the three blades. We show thermal signatures of damage in rotor blades and contrast them with structural characteristics by comparing the three blades. In addition to measurements in industrial environments, laboratory measurements are shown and compared to simulations. The long-term goal is to simulate the influence of different weather parameters and thus gain a better understanding of measurements in the field. The results shown here can be seen as one step towards industrial application.</abstract>
    <identifier type="url">https://spie.org/defense-commercial-sensing/presentation/Weather-dependent-passive-thermography-of-unheated-wind-turbine-blades/12109-19?SSO=1</identifier>
    <enrichment key="eventName">Defense + Commercial Sensing 2022</enrichment>
    <enrichment key="eventPlace">Orlando, Florida, USA</enrichment>
    <enrichment key="eventStart">3.4.2022</enrichment>
    <enrichment key="RelatedIdentifier">https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/54943</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">true</enrichment>
    <enrichment key="InvitedTalks">0</enrichment>
    <author>Michael Stamm</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Passive thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Wind energy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>FEM simulations</value>
    </subject>
    <collection role="ddc" number="621">Angewandte Physik</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Energie</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Präsentation</collection>
  </doc>
  <doc>
    <id>55818</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>lecture</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Towards automated passive thermography of wind turbine blades</title>
    <abstract language="eng">Up to now, the inspection of wind turbines by industrial climbers has been considered "state of the art". However, many aspects like ever-larger wind turbines, minimizing the risk for man and machine and the advancing digitalization make modern and automated inspection methods indispensable. A particular interest here is contactless and remote methods that can be used with drones instead of climbing robots. The work presented here contributes to the long-term goal of making autonomous and advanced inspections of wind turbine rotor blades using drones ready for industrial use.&#13;
Besides visual inspection, only a few inspection methods are capable of non-contact inspection on an industrial scale. Passive thermography can serve as such a contactless and digital inspection method and is well known for its applications in the inspection of buildings or electrical circuits. It can even sense both near-surface and subsurface defects. The sensitivity to subsurface defects makes one advantage of thermography over visual inspections. As a digital inspection method, it is generally also more objective and offers more comparability. For example, defects and their extent can be easily monitored and compared over time. However, its industrial application relies on thermal gradients in the inspected object such that a temperature contrast exists between damaged and sound areas. This also applies to large unheated structures such as wind turbine rotor blades, which do not have an intrinsic temperature gradient and at the same time cannot be easily heated externally.&#13;
Under certain weather conditions, a change of the environmental temperature or the solar loading conditions can provide the necessary thermal gradients to make passive thermography viable for the in-service inspection of rotor blades. For a reliable use of passive thermography on "thermal passive" components, the incorporation of these environmental conditions in the planning and evaluation of thermal inspections is crucial. &#13;
Compared to many other objects and buildings, wind turbine blades have varying and often unknown complex internal structures depending on the model. A special method is therefore required, that can be used independently of the internal structure of the blades and that relates the individual thermograms of the three rotor blades to each other. This allows the distinction between the thermal response of design-specific structural features and damages or irregularities between the three blades. &#13;
In this work we present thermal signatures of rotating in-service rotor blades taken under industrial relevant conditions. These thermograms show surface and subsurface damages and irregularities which we contrast with structural design features by referencing the three blades to each other. In addition, we examine the strong influence of different weather conditions on the inspection results. A direct comparison of measured results with inspection reports from industrial climbers serves as a benchmark.</abstract>
    <enrichment key="eventName">EERA DeepWind conference</enrichment>
    <enrichment key="eventPlace">Trondheim, Norway</enrichment>
    <enrichment key="eventStart">19.01.2022</enrichment>
    <enrichment key="eventEnd">21.01.2022</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="InvitedTalks">0</enrichment>
    <author>Michael Stamm</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Wind energy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Passve IR</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Rotor blades</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Maintenance</value>
    </subject>
    <collection role="ddc" number="621">Angewandte Physik</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Energie</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Präsentation</collection>
  </doc>
  <doc>
    <id>55819</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>lecture</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Towards the in-service blade inspection by  ground-based passive thermography</title>
    <abstract language="eng">Until today, the optical inspection of rotor blades by industrial climbers is considered state of the art. However, both more and larger rotor blades and the increasing digitalization of maintenance work make modern inspection methods increasingly necessary. In this context, passive thermography can serve as a useful digital technique for in-service inspection of wind turbine blades. Unlike active thermography, this inspection method does not require an active heat source but takes advantage of heating by the sun and diurnal temperature fluctuations. This allows inspections from the ground during operation and does not require shutting down the wind turbine. However, an inspection with passive thermography is highly weather dependent. Thus, the already weak thermal signatures formed due to internal structures and possible internal damage are only strong enough under certain weather conditions.&#13;
To obtain meaningful inspection results despite the relatively small thermal differences between intact and defective components, three aspects are crucial:&#13;
1. Measurements should be taken at the time of optimum weather conditions. It must be kept in mind that different internal damage will be revealed by thermal signatures under different weather conditions. &#13;
2. The thermal signature of the rotor blades, including possible damages, must be simulated with FEM simulations. In this way, the influence of different weather conditions can be predicted but also understood in the aftermath. &#13;
3. The temperature differences between identically designed and assembled rotor blades must be considered to analyze variations between blades. &#13;
This work will address all these aspects and show, based on field measurements under industrial conditions (exemplarily shown in figure 1), laboratory measurements and FEM simulations, which steps must be taken to establish passive thermography as an industrial inspection method.</abstract>
    <enrichment key="eventName">EERA SP7 Rotor Blade workshop</enrichment>
    <enrichment key="eventPlace">Roskilde, Denmark</enrichment>
    <enrichment key="eventStart">23.06.2022</enrichment>
    <enrichment key="eventEnd">24.06.2022</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">true</enrichment>
    <enrichment key="InvitedTalks">0</enrichment>
    <author>Michael Stamm</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Wind energy</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Maintenance</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Rotor blades</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Passive IRT</value>
    </subject>
    <collection role="ddc" number="621">Angewandte Physik</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Energie</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Präsentation</collection>
  </doc>
  <doc>
    <id>55823</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>deu</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>lecture</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="deu">In situ Charakterisierung von Reparaturen in GFK Schalenstrukturen mittels Lockin Thermografie und Felddehnungsmessungen</title>
    <abstract language="deu">Die tiefgreifende Reparatur von Faserverbundwerkstoffen stellt durch deren inneren Aufbau eine besondere Herausforderung dar, die unter anderem bei der Instandhaltung von Rotorblättern von Windkraftanlagen zum Tragen kommt. Um die Reparaturen von Rotorblattschalen zu untersuchen und zu optimieren, wurden an der BAM Sandwich-Schalenprüfkörper aus Glasfaserkunststoff (GFK) entwickelt. Nachdem in diese Schalenprüfkörper Modell-Reparaturen eingebracht wurden, werden zyklische mechanische Ermüdungsversuche bis zum Bruch durchgeführt. Vorrangiges Ziel ist es, den Einfluss verschiedener Reparaturvariablen auf die Ermüdungslebensdauer der Struktur zu verstehen, sowie die stabilste Reparaturmethode zu bestimmen.&#13;
Während der zyklischen Lastversuche wurden regelmäßig in-situ Messungen mit einer Thermografie Kamera und einem optischen Felddehnungsmesssystem durchgeführt. Durch beide Messmethoden lassen sich Eigenschaften der Probekörper zeitlich und räumlich aufgelöst darstellen. &#13;
Während die Felddehnungsmessungen Aufschluss über die Verformung an der Oberfläche geben, erfasst die thermische Inspektion Temperaturänderungen an der Oberfläche. Besonders die thermografischen Messwerte bilden hier das oberflächennahe Volumen ab, in dem sich Temperaturänderungen an der Oberfläche abzeichnen. &#13;
Die Messergebnisse beider Systeme stellen also verschiede aber korrelierte Parameter dar. Denn die zyklische Belastung (Bewegung) ruft eine periodische Temperaturänderung im Bauteil hervor. Dieser so genannte Thermoeleastische Effekt kann durch eine Lockin-Analyse der Temperaturtransienten (Temperaturverläufe) nachgewiesen werden. Die räumliche Darstellung der thermischen Effekte lässt Rückschlüsse auf die tatsächliche Lastverteilung im Probekörpervolumen zu.&#13;
Darüber hinaus führen nichtelastische Verformungen zu einer zusätzlichen Wärmefreisetzung, die durch geeignete Auswerteverfahren ebenfalls nachgewiesen werden können. Entsprechende Hot-Spots in der räumlichen Verteilung erlauben eine frühzeitige Erkennung besonders belasteter Bereiche lange vor dem eigentlichen Bauteil-Versagen. Das gestattet die Lokalisierung des Initial-Schadens, was mit der numerischen Spannungsanalyse korreliert werden kann und  die Entwicklung und Bewertung verschiedener Reparaturstrategien.</abstract>
    <enrichment key="eventName">DGZfP Jahrestagung 2022</enrichment>
    <enrichment key="eventPlace">Kassel, Germany</enrichment>
    <enrichment key="eventStart">23.05.2022</enrichment>
    <enrichment key="eventEnd">25.05.2022</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="opus.doi.autoCreate">false</enrichment>
    <enrichment key="opus.urn.autoCreate">true</enrichment>
    <enrichment key="InvitedTalks">0</enrichment>
    <author>Michael Stamm</author>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>Lockin Thermografie</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>GFK</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>NDT</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>ZfP</value>
    </subject>
    <collection role="ddc" number="621">Angewandte Physik</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Energie</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="literaturgattung" number="">Präsentation</collection>
  </doc>
  <doc>
    <id>55459</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>1</pageFirst>
    <pageLast>15</pageLast>
    <pageNumber/>
    <edition/>
    <issue>15</issue>
    <volume>22</volume>
    <type>article</type>
    <publisherName>MDPI</publisherName>
    <publisherPlace>Basel</publisherPlace>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>1</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Learned block iterative shrinkage thresholding algorithm for photothermal super resolution imaging</title>
    <abstract language="eng">Block-sparse regularization is already well known in active thermal imaging and is used for multiple-measurement-based inverse problems. The main bottleneck of this method is the choice of regularization parameters which differs for each experiment. We show the benefits of using a learned block iterative shrinkage thresholding algorithm (LBISTA) that is able to learn the choice of regularization parameters, without the need to manually select them. In addition, LBISTA enables the determination of a suitable weight matrix to solve the underlying inverse problem. Therefore, in this paper we present LBISTA and compare it with state-of-the-art block iterative shrinkage thresholding using synthetically generated and experimental test data from active thermography for defect reconstruction. Our results show that the use of the learned block-sparse optimization approach provides smaller normalized mean square errors for a small fixed number of iterations. Thus, this allows us to improve the convergence speed and only needs a few iterations to generate accurate defect reconstruction in photothermal super-resolution imaging.</abstract>
    <parentTitle language="eng">Sensors</parentTitle>
    <identifier type="doi">10.3390/s22155533</identifier>
    <identifier type="urn">urn:nbn:de:kobv:b43-554598</identifier>
    <identifier type="issn">1424-8220</identifier>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="date_peer_review">10.08.2022</enrichment>
    <enrichment key="RelatedIdentifier">https://nbn-resolving.org/urn:nbn:de:kobv:b43-525364</enrichment>
    <licence>Creative Commons - CC BY - Namensnennung 4.0 International</licence>
    <author>J. C. Hauffen</author>
    <author>L. Kästner</author>
    <author>Samim Ahmadi</author>
    <author>P. Jung</author>
    <author>G. Caire</author>
    <author>Mathias Ziegler</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Laser</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Machine learning</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Optimization</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Non-destructive testing</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>NDT</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Neural network</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Defect reconstruction</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Block-sparsity</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Active thermal imaging</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Regularization</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Laser thermography</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="literaturgattung" number="">Verlagsliteratur</collection>
    <collection role="fulltextaccess" number="">Datei für die Öffentlichkeit verfügbar ("Open Access")</collection>
    <collection role="unnumberedseries" number="">Wissenschaftliche Artikel der BAM</collection>
    <thesisPublisher>Bundesanstalt für Materialforschung und -prüfung (BAM)</thesisPublisher>
    <file>https://opus4.kobv.de/opus4-bam/files/55459/sensors-22-05533.pdf</file>
  </doc>
  <doc>
    <id>55475</id>
    <completedYear/>
    <publishedYear>2021</publishedYear>
    <thesisYearAccepted/>
    <language>deu</language>
    <pageFirst>104</pageFirst>
    <pageLast>119</pageLast>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume>61</volume>
    <type>conferenceobject</type>
    <publisherName>Hendrik Bäßler</publisherName>
    <publisherPlace>Berlin</publisherPlace>
    <creatingCorporation>Brandenburgisches Landesamt für Denkmalpflege und Archäologisches Landesmuseum</creatingCorporation>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="deu">Thermische Kontraste - Der Blick hinter die Fassade</title>
    <abstract language="deu">Die Thermografie beruht auf der bildlichen Darstellung von Temperaturunterschieden oder auch thermischen Kontrasten an der Oberfläche eines Untersuchungsobjektes. Diese bilden sich nur her-aus, wenn sich das Untersuchungsobjekt gerade erwärmt oder abkühlt. Der Beitrag erklärt mittels eines stark vereinfachten Modells die Entstehung solcher Kontraste als dynamischen Effekt verschiedener Abkühlgeschwindigkeiten. Neben Laborergebnissen werden beispielhaft einige Ergeb-nisse von einem mittelalterlichen Baudenkmal präsentiert, um das Verständnis für die thermografische Inspektion von Fassaden zu vertiefen.</abstract>
    <parentTitle language="deu">Bildgebende Verfahren - Trends und Fallbeispiele zur zerstörungsfreien Untersuchung und Erhaltung von Kulturerbe - "Ich sehe was, was Du nicht siehst"</parentTitle>
    <identifier type="isbn">978-3-945880-90-6</identifier>
    <enrichment key="eventName">14. Konservierungswissenschaftliches Kolloquium Berlin Brandenburg</enrichment>
    <enrichment key="eventPlace">Berlin, Germany</enrichment>
    <enrichment key="eventStart">12.11.2021</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <enrichment key="bibliotheksstandort">Pb 572</enrichment>
    <author>Rainer Krankenhagen</author>
    <author>Christiane Maierhofer</author>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>Ablösungen</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>Aktive Thermografie</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>Bauthermografie</value>
    </subject>
    <subject>
      <language>deu</language>
      <type>uncontrolled</type>
      <value>Metallanker</value>
    </subject>
    <collection role="ddc" number="624">Ingenieurbau</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Infrastruktur</collection>
    <collection role="literaturgattung" number="">Verlagsliteratur</collection>
    <collection role="fulltextaccess" number="">Datei im Netzwerk der BAM verfügbar ("Closed Access")</collection>
    <collection role="fulltextaccess" number="">Physisches Exemplar in der Bibliothek der BAM vorhanden ("Hardcopy Access")</collection>
  </doc>
  <doc>
    <id>55122</id>
    <completedYear/>
    <publishedYear>2022</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst/>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume/>
    <type>poster</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>--</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Thermographic super resolution reconstruction using 2D pseudo-random pattern illumination</title>
    <abstract language="eng">Thermographic non-destructive testing is based on the interaction of thermal waves with inhomogeneities. The propagation of thermal waves from the heat source to the inhomogeneity and to the detection surface according to the thermal diffusion equation leads to the fact that two closely spaced defects can be incorrectly detected as one defect in the measured thermogram. In order to break this spatial resolution limit (super resolution), the combination of spatially structured heating and numerical methods of compressed sensing can be used. The improvement of the spatial resolution for defect detection then depends in the classical sense directly on the number of measurements. Current practical implementations of this super resolution detection still suffer from long measurement times, since not only the achievable resolution depends on performing multiple measurements, but due to the use of single spot laser sources or laser arrays with low pixel count, also the scanning process itself is quite slow. With the application of most recent high-power digital micromirror device (DMD) based laser projector technology this issue can now be overcome.</abstract>
    <identifier type="url">https://indico.ung.si/event/5/contributions/237/</identifier>
    <identifier type="urn">urn:nbn:de:kobv:b43-551224</identifier>
    <enrichment key="eventName">ICPPP21: International Conference on Photoacoustic and Photothermal Phenomena</enrichment>
    <enrichment key="eventPlace">Bled, Slovenia</enrichment>
    <enrichment key="eventStart">19.06.2022</enrichment>
    <enrichment key="eventEnd">24.06.2022</enrichment>
    <enrichment key="opus.source">publish</enrichment>
    <licence>Creative Commons - CC BY - Namensnennung 4.0 International</licence>
    <author>Mathias Ziegler</author>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Thermography</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Super resolution</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>NDT</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Inspection</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>Internal defects</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>DMD</value>
    </subject>
    <subject>
      <language>eng</language>
      <type>uncontrolled</type>
      <value>DLP</value>
    </subject>
    <collection role="ddc" number="543">Analytische Chemie</collection>
    <collection role="institutes" number="">8 Zerstörungsfreie Prüfung</collection>
    <collection role="institutes" number="">8.3 Thermografische Verfahren</collection>
    <collection role="themenfelder" number="">Chemie und Prozesstechnik</collection>
    <collection role="fulltextaccess" number="">Datei für die Öffentlichkeit verfügbar ("Open Access")</collection>
    <collection role="literaturgattung" number="">Präsentation</collection>
    <thesisPublisher>Bundesanstalt für Materialforschung und -prüfung (BAM)</thesisPublisher>
    <file>https://opus4.kobv.de/opus4-bam/files/55122/ICPPP_Poster_Lecompagnon.pdf</file>
  </doc>
</export-example>
