Abstract
Non-destructive methods are of great interest for the analysis of cultural
heritage. Among the different possible techniques, this paper presents a low cost prototype
based on the emission and reception of airborne ultrasound without direct contact with the
test specimen. We successfully performed a method test for the detection of brick joints
under a XVth century Renaissance fresco of the Metropolitan Cathedral of the city of
Valencia (Spain). Both laboratory and in situ results are in agreement. Using this prototype
system, an early moisture detection system has been installed in the dome that supports the
fresco. The result is encouraging and opens interesting prospects for future research.
