The technology has been developed over the past 25 years, implementing new innovative components during time. The methodology provides a set of 2D acoustic images in different frequency intervals, for revealing the structural damage (detachments, delaminations, structural weakening) in multi-layer structures and artworks (mural paintings, frescoes, ceramic panels, panel paintings). Recently, interesting results have been obtained in studies of the water related deterioration effects on antique masonry structures. The method is not yet part of protocols and national/international standards.
The contactless device operates in the audio frequency interval, measuring the acoustic energy absorption. Two possible configurations: multi-point and single-point. The equipment is composed of a transmit-receiving unit (acoustic source and microphone), a central unit for control and processing and, for the multi-pointanalyses, an XY scanning unit for the construction of (n x m) matrices.
The device can mount both traditional sources and innovative highly directive sources, to increase spatial resolution. The methodology is non-invasive, and the sound levels are similar to normal speech; the contactless equipment is also easily transportable for on-site diagnostics. Recently, the central control unit was renewed in an integrated configuration, in collaboration with ENEA research groups and METAPROJECTS Research Centre, part of the Emilia-Romagna High Technology Network.
The current advancements are oriented towards a low-cost, compact and flexible configuration for optimal use in situ and in complex contexts. Currently, there is only one low-cost acoustic technology that can represent a competitor, PICUS, which however has a different concept, it is configured for restorers/operators use not specialized in acoustics. However, the PICUS system works in contact via a mechanical probe, and presents a narrower frequency band. The level of development is similar.