Article: ESPI for the investigation of wooden art objects (2010)

Title: Simple Electronic Speckle Pattern Interferometer (ESPI) for the investigation of wooden art objects
Authors: Lukasz Lasyk, Michal Lukomski, Lukasz Bratasz
Reference: Proceedings of the COST Action IE0601 Annual Conference, Braga, Portugal, to be published by the Florence University Press in 2010

Link: http://heritagescience.pl/... (pdf, 1.78 Mb)


Abstract

The development of a simple electronic speckle pattern interferometer (ESPI) for the non-invasive, non-contact detection and characterization of early-stage damage of painted surfaces, like fracturing and layer separation, is reported. The ESPI system developed relies on the analysis of sound-induced vibration of the investigated surfaces. A simplified optical system as well as special algorithms for the analysis of interferograms were developed for the purpose of gaining precise information on the different indicators of the destruction process: the characteristic resonance frequency for the damaged area, its size and the spatial distribution of the vibration amplitude. The technique was applied to trace damage in specimens of painted wood subjected to damaging cycles of dimensional change.