Non-destructive testing (NDT) methods used for the study of stone frescoes

Stefano Sfarra, Philipp Huke, Panagiotis Theodorakeas, Domenica Paoletti, Nicolas P. Avdeledis, Dario Ambrosini, Reiner Klattenhoff, Maria Koui

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)


The value of cultural heritage objects is very high, requiring an observation technique that is safe, highly efficient, and sensitive enough to detect defects that occur in these objects. A combination of non-destructive testing (NDT) methods that meet these requirements increases the probability of detection (POD) and reduces the chance of false detection (false positives or false negatives). In this work, the applicability of optical, infrared and ultrasonic techniques, originally developed for industry, in the architectural restoration field is examined. As an example, we investigate a brick basis covered with two plaster layers containing artificial defects (crack and detachment) hidden in the sample. Squares of different colours have been painted with the last layer comparable to a real fresco, constituting a challenge for thermographic measurements (e.g., in pulse thermography, data is affected by non-uniform heating and local variation of thermal emission). The advantages and disadvantages of Holographic Interferometry (Double-Exposure-DE-), Digital Speckle Photography (DSP), Shearography, Transient Thermal Thermography and Ultrasonic Testing are discussed with respect to their ability to detect the previously described defects.

Original languageEnglish
Title of host publicationNDT in Progress 2011 - 6th International Workshop of NDT Experts, Proceedings
PublisherBrno University of Technology
Number of pages10
ISBN (Electronic)9788021443396
Publication statusPublished - 2011
Externally publishedYes
Event6th International Workshop NDT in Progress 2011 - Prague, Czech Republic
Duration: 10 Oct 201112 Oct 2011


Conference6th International Workshop NDT in Progress 2011
CountryCzech Republic


  • Defect
  • Digital speckle photography (DSP)
  • Fresco
  • Holographic interferometry (HI)
  • Shearography
  • Transient thermography
  • Ultrasonic Testing

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)

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