Quantitative techniques to characterize thermomechanical effects of light on canvas paintings are necessary in order to
better understand the deleterious effects that light has on precious art collections in museum exhibitions. In this paper,
we present advances in the development of a customized laser shearography system for temporal characterization of inplane
displacements of canvas paintings when subjected to specific lighting conditions. The shearography system is
synchronized with a thermal IR camera and concomitant measurements of derivatives of displacements along two
orthogonal shearing directions as well as thermal fields are performed. Due to the nature of the measurements, we have
developed real-time temporal phase unwrapping algorithms and high-resolution Fast Fourier Transform (FFT) methods
to calibrate applied shearing levels. In addition, we are developing methods to isolate thermally-induced components
from randomly-induced mechanical vibrations that occur in museum environments by application of IR imaging data.
Representative examples are shown, which illustrate capabilities to measure, detect, and map crack propagation as a
function of lighting conditions and time.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
M. K. Meybodi ; I. Dobrev ; P. Klausmeyer ; E. J. Harrington and C. Furlong
"Investigation of thermomechanical effects of lighting conditions on canvas paintings by laser shearography", Proc. SPIE 8494, Interferometry XVI: Applications, 84940A (September 13, 2012); doi:10.1117/12.958089; http://dx.doi.org/10.1117/12.958089