A Contact-less Method for Monitoring the Detachments in the Architectural Coverings of Ancient Structures by using 'ULTRAINO'

Detecting the presence, the position and the extension of the detachments in architectural coverings is at the base of the analysis of the state of conservation of ancient structures. Many non-destructive investigation methodologies have been used, and the ultrasound technique applied through the use of parametric transducers appears be very promising. The use of parametric transducers to detect structural defects has been widely proven, but normally the systems 'off the shelf' are not focused: these systems have beams with dimensions of the order of tens of cm, Recently, the introduction of a parametric transducer driven by an Arduino board, called Ultraino, has allowed to have available a focused parametric transducer at very low cost. The use of 'Ultraino' permits to obtain beams with focal areas of the order of millimeters, at very small distances from the radiating device. This advantage, combined with the possibility of driving the device by a Matlab script, permits to implement the well-known technique of the measurement of the impulsive response in the audio range, and extract the acoustic reflectivity of the superficial point under test. Finally, the entire instrumentation has a very low price and it is easily portable and usable in situ.