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Journal of Spectroscopy
Volume 2013 (2013), Article ID 380536, 13 pages
http://dx.doi.org/10.1155/2013/380536
Research Article

Surface Investigation of Photo-Degraded Wood by Colour Monitoring, Infrared Spectroscopy, and Hyperspectral Imaging

1Department of Cultural Heritage Sciences, University of Tuscia, Largo dell’Università, 01100 Viterbo, Italy
2Department of Chemical Engineering Materials & Environment, Sapienza-Rome University, Via Eudossiana 18, 00184 Rome, Italy
3Department of Agriculture, Forests, Nature and Energy (DAFNE), University of Tuscia, Via San Camillo de Lellis, 01100 Viterbo, Italy

Received 30 May 2013; Revised 29 July 2013; Accepted 13 August 2013

Academic Editor: Luciano Bachmann

Copyright © 2013 Giorgia Agresti et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The aim of this investigation is to study the changes occurring on the surface of poplar wood exposed to artificial irradiation in a Solar Box. Colour changes were monitored with a reflectance spectrophotometer. Surface chemical modifications were evaluated by measuring the infrared spectra. Hyperspectral imaging was also applied to study the surface wood changes in the visible-near infrared and the short wave infrared wavelength ranges. The data obtained from the different techniques were compared to find the possible correlations in order to evaluate the applicability of the Hyperspectral imaging to investigate wood modifications in a non-invasive modality. The study of colour changes showed an important variation due to photo-irradiation which is the greatest change occurring within the first 24 hours. Infrared spectroscopy revealed that lignin degrades mainly in the first 48 hours. Concerning Hyperspectral imaging, the spectral features in the visible-near infrared range are mainly linked to the spectral shape, whereas in the short wave infrared cellulose and lignin affect shape and reflectance levels. The proposed approach showed that a correlation can be established between colour variation and wood degradation in the visible-near infrared range; furthermore in the short wave infrared region surface chemical changes can be assessed.