Abstract-Terahertz frequency-wavelet domain deconvolution for stratigraphic and subsurface investigation of art painting

Junliang Dong, J. Bianca Jackson, Marcello Melis, David Giovanacci, Gillian C. Walker, Alexandre Locquet, John W. Bowen, and D. S. Citrin

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-24-23-26972

Terahertz frequency-wavelet deconvolution is utilized specifically for the stratigraphic and subsurface investigation of art paintings with terahertz reflective imaging. In order to resolve the optically thin paint layers, a deconvolution technique is enhanced by the combination of frequency-domain filtering and stationary wavelet shrinkage, and applied to investigate a mid-20th century Italian oil painting on paperboard, After Fishing, by Ausonio Tanda. Based on the deconvolved terahertz data, the stratigraphy of the painting including the paint layers is reconstructed and subsurface features are clearly revealed, demonstrating that terahertz frequency-wavelet deconvolution can be an effective tool to characterize stratified systems with optically thin layers.

© 2016 Optical Society of America

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Abstract-Terahertz pulse imaging in archaeology

• J. Bianca Jackson, 
• Julien Labaune, 
• Rozenn Bailleul-Lesuer, 
• Laura D’Alessandro, 
• Alison Whyte,
• John W. Bowen, 
• Michel Menu, 
• Gerard Mourou
• http://link.springer.com/article/10.1007/s12200-014-0446-y
  
  

The work presented in this paper was performed at the Oriental Institute at the University of Chicago, on objects from their permanent collection: an ancient Egyptian bird mummy and three ancient Sumerian corroded copper-alloy objects. We used a portable, fiber-coupled terahertz (THz) time-domain spectroscopic imaging system, which allowed us to measure specimens in both transmission and reflection geometry, and present time- and frequency-based image modes. The results confirm earlier evidence that THz imaging can provide complementary information to that obtainable from X-ray computed tomography (XRCT) scans of mummies, giving better visualisation of low density regions. In addition, we demonstrated that THz imaging can distinguish mineralized layers in metal artifacts.