Artwork diagnostics with fiber-optic digital speckle pattern interferometry.

The possibility of employing a digital speckle pattern interferometer with optical fibers for nondestructive testing of artwork has been evaluated. A simple and accurate fiber-optic interferometer, able to perform real-time measurements in a hostile environment, has been realized with a minimum of optical components and a minimum of adjustments. As a result a deformation map of wooden panel paintings or mural frescoes under thermal stress may be depicted. Experimental results, obtained by the application of this interferometer both to laboratory models and to mural frescoes in situ, are presented.