Abstract
Within the framework of heritage conservation, non-destructive inspection methods are of interest, especially ultrasonic investigation which is the only method with a direct and physical relationship with the mechanical state of the medium. Heritage conservation requires special attention when using ultrasonic equipment, especially for statues. To prevent mechanical or esthetic deterioration, direct contact of the transducers with the surface should be avoided, as well as coupling agent such as grease or echographic gel.The aim of this study is to show the potential of the use of laser vibrometry in this context. The method presented here is funded on 3 steps. (i) Using 3D photogrammetry, the geometrical model is built. (ii) Ultrasonic signals acquisition is performed using a scanner laser vibrometer monitored by a camera. (iii) The ultrasonic image is built by combining the geometrical model and ultrasonic signal processing. The absolute amplitude measure provided by the laser is also employed to reconstruct both velocity and attenuation maps. This method is applied on a Roman marble statue of the site museum of Alba-La-Romaine (MuséAl, Ardèche, France). The results show the possibility to image both the marble homogeneity in the bulk of the statue as well as crack profiles at the surface.