• Treffer 24 von 420
ZurĂŒck zur Trefferliste

Overcoming the Spatial Resolution Limits imposed by the Thermal MTF with Thermographic Photothermal Super Resolution Reconstruction

  • The achievable spatial resolution of active thermographic testing is inherently limited by the diffusive nature of heat conduction in solids. This degradation of the achievable spatial resolution for a semi-infinite body acting on a defect signal can be approximated by spatial convolution with the Green’s function of the heat PDE. As the degradation in spatial resolution is dependent on the depth 𝐿, a common rule of thumb specifies that for proper detection, any defect should feature a spatial extension greater or equal to the depth it is located at. However, as the exact shape of a defect can have a large impact on its severity, at best a proper reconstruction of the defect shape should be performed, which therefore must also deal with the aforementioned adverse effects of heat conduction. One recent method to overcome the spatial resolution limit of thermographic testing is the photothermal super resolution reconstruction method. It is based on performing multiple activeThe achievable spatial resolution of active thermographic testing is inherently limited by the diffusive nature of heat conduction in solids. This degradation of the achievable spatial resolution for a semi-infinite body acting on a defect signal can be approximated by spatial convolution with the Green’s function of the heat PDE. As the degradation in spatial resolution is dependent on the depth 𝐿, a common rule of thumb specifies that for proper detection, any defect should feature a spatial extension greater or equal to the depth it is located at. However, as the exact shape of a defect can have a large impact on its severity, at best a proper reconstruction of the defect shape should be performed, which therefore must also deal with the aforementioned adverse effects of heat conduction. One recent method to overcome the spatial resolution limit of thermographic testing is the photothermal super resolution reconstruction method. It is based on performing multiple active thermographic measurements on the same region of interest (ROI) with varying spatially structured heating and subsequent numerical reconstruction of the measured defect signals by solving a severely ill-posed inverse reconstruction problem relying on heavy regularization. By extending the experimental implementation of the method to make use of random-pixel patterns projected onto the ROI using a laser-coupled DLP-projector, defect reconstructions can now be performed within a reasonable time frame (~15 min per ROI) at high accuracy. Compared to conventional thermographic testing methods, the photothermal super resolution reconstruction stands out by resulting in a sparse representation of the defect structure of the ROI, making it especially well-suited to further automatic defect classification and quality assurance measures in an Industry 4.0 context.
zeige mehrzeige weniger

Volltext Dateien herunterladen

  • Presentation_Lecompagnon_split.pdf
    eng
  • Abstract_Presentation_Lecompagnon.pdf
    eng

Metadaten exportieren

Weitere Dienste

Teilen auf Twitter Suche bei Google Scholar Anzahl der Zugriffe auf dieses Dokument
Metadaten
Autor*innen:Julien LecompagnonORCiD
Koautor*innen:Philipp Daniel Hirsch, C. Rupprecht, Mathias Ziegler
Dokumenttyp:Vortrag
Veröffentlichungsform:PrÀsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2023
Organisationseinheit der BAM:8 Zerstörungsfreie PrĂŒfung
8 Zerstörungsfreie PrĂŒfung / 8.0 Abteilungsleitung und andere
DDC-Klassifikation:Naturwissenschaften und Mathematik / Chemie / Analytische Chemie
Freie Schlagwörter:DLP; Internal defects; NDT; Super resolution; Thermography
Themenfelder/AktivitÀtsfelder der BAM:Chemie und Prozesstechnik
Veranstaltung:INTERNATIONAL SCHOOL OF QUANTUM ELECTRONICS: 67th Course: Progress in Photoacoustic & Photothermal Phenomena
Veranstaltungsort:Erice, Italy
Beginndatum der Veranstaltung:24.09.2023
Enddatum der Veranstaltung:01.10.2023
VerfĂŒgbarkeit des Dokuments:Datei im Netzwerk der BAM verfĂŒgbar ("Closed Access")
Datum der Freischaltung:04.10.2023
Referierte Publikation:Nein
Eingeladener Vortrag:Nein
Einverstanden
Diese Webseite verwendet technisch erforderliche Session-Cookies. Durch die weitere Nutzung der Webseite stimmen Sie diesem zu. Unsere Datenschutzerklärung finden Sie hier.