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

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

doi:10.1364/oe.24.026972

Abstract

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.

Highlights

Terahertz (THz) imaging, which can provide a nondestructive, noncontact, and nonionizing modality for characterizing materials, is emerging as a promising technique in the field of cultural-heritage conservation [1]
A mid-20th Italian oil painting on paperboard, After Fishing, by Ausonio Tanda is systematically examined with the method
THz frequency-wavelet deconvolution is applied to the THz raw data, and the stratigraphy of the paint layers is successfully reconstructed across the painting based on the deconvolved data

Summary

Introduction

Terahertz (THz) imaging, which can provide a nondestructive, noncontact, and nonionizing modality for characterizing materials, is emerging as a promising technique in the field of cultural-heritage conservation [1]. THz imaging can provide information in depth to investigate the stratigraphy and hidden features or damages in artworks, which is of great interest for conservation and restoration, as well as for art-historical studies. THz imaging has shown great potential in the cultural-heritage arena, enabling the characterization of features in stone sculpture and in architecture [2], wooden objects [3] and tree rings [4], clay artifacts [5], written papyrus [6], and even ancient Egyptian mummies [7, 8]. In addition to revealing such subsurface features, the stratigraphic structure of art paintings is of general interest, since it may be used to understand the process of the painting’s creation

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Conclusion