Laser interference-based techniques and applications in structural inspection of works of art.

Techniques based on laser interferometry principles provide great potential to retrieve imperceptible bulk information regarding the physical and mechanical condition of complex and inhomogeneous structures. This review presents the progress in and prospects for optical coherent interferometry techniques in artwork conservation applications, in particular concerning the performance of the developed instrumentations and methodologies. Each of the state-of-the-art techniques is introduced by reference to fundamental principles, basic equations and general optical geometry. In this context, a brief introduction to fundamental principles governing the optical coherent interferometry measurements is presented prior to discussion on performance. Some exemplary results demonstrating that bulk interferometric signals can be obtained from rough artwork surfaces are shown and their suitability is reviewed. Several opportunities for art conservation research and applications are summarised and discussed.