Multi-dimensional reconstruction of internal defects in additively manufactured steel using photothermal super resolution combined with virtual wave based image processing

Samim Ahmadi, Gregor Thummerer, Stefan Breitwieser, G. Mayr, Julien Lecompagnon, Peter Burgholzer, Peter Jung, Giuseppe Caire, Mathias Ziegler

Research output: Contribution to journalArticlepeer-review

Abstract

We combine three different approaches to greatly enhance the defect reconstruction ability of active thermographic testing. As experimental approach, laser-based structured illumination is performed in a step-wise manner. As an intermediate signal processing step, the virtual wave concept is used in order to effectively convert the notoriously difficult to solve diffusion-based inverse problem into a somewhat milder wave-based inverse problem. As a final step, a compressed-sensing based optimization procedure is applied which efficiently solves the inverse problem by making advantage of the joint sparsity of multiple blind measurements. To evaluate our proposed processing technique, we investigate an additively manufactured stainless steel sample with eight internal defects. The concerted super resolution approach is compared to conventional thermographic reconstruction techniques and shows an at least four times better spatial resolution.
Original languageEnglish
JournalIEEE Transactions on Industrial Informatics
DOIs
Publication statusPublished - 2021

Keywords

  • active thermography
  • additively manufactured stainless steel
  • ADMM
  • block regularization
  • internal defects
  • joint sparsity
  • laser excitation
  • multi-dimensional reconstruction
  • photothermal super resolution
  • virtual waves

Fingerprint Dive into the research topics of 'Multi-dimensional reconstruction of internal defects in additively manufactured steel using photothermal super resolution combined with virtual wave based image processing'. Together they form a unique fingerprint.

Cite this