PICUS: A Pocket-Sized System for Simple and Fast Non-Destructive Evaluation of the Detachments in Ancient Artifacts

Abstract

An innovative, robust method has been developed, based on the use of a simple, compact, expressly designed device, named PICUS (the ‘woodpecker’ in ancient Latin), and inspired by the auscultation method carried out by the experts in the field of conservation of cultural heritage. This method entails gently knocking the surface, controlling and measuring the impact time of the stroke’s force, recording the generated sound, comparing the acquired sound with a reference sound by calculating the cross-correlation function, and its maximum, as a measure of the detachment. In a nutshell, it performs an analysis similar to that carried out by a professional who performs a routine examination on the detachments by hand. The experimental apparatus consists of a probe made of an electromechanical percussion element that gently taps the surface producing a sound, a force sensor purposely developed to measure the impact force, and a microphone, all connected with an Arduino-like low cost board, to record and elaborate the sounds and the force sensor signal. The probe XY position on the scene is recognized using an infra-red (IR) system with a low-cost IR camera and an IR light-emitting diode (IR-LED) positioned on the probe. The “tapper” and the microphone replace the hand and the ear of a conservator carrying out a detachment investigation, while the comparison with a reference is the typical mind process of a professional restorer. The result is the fusion of the microphone data and the force sensor data.

An automated sonic tomography system for the inspection of historical masonry walls

“…The automation of acoustic inspection has been a recent subject of many studies in the field of inspection of concrete infrastructures, aiming to detect flaws and assess their structural integrity [ Watanabe et al ., 2015 ; Li et al ., 2017 ; Feng et al ., 2021 ; Hoxha et al ., 2022 ]. Automated hitting devices have been developed to detect detachment of tiled surfaces [ Caliano et al ., 2021 ]. Moreover, the possibility of automatize the inspection of infrastructure using Unmanned Aerial Vehicles (UAVs) has also been a subject of recent research, either by exploring their capabilities for constant inspection tasks [ González-deSantos et al ., 2019 ] or by mounting hitting systems to the UAVs for hammering inspections [ Ichikawa et al ., 2017 ; Nishimura et al ., 2022 ].…”

Acoustic characteristics and defects of adhesion of ancient construction materials using the PICUS system

“…Results from the mapping procedure will be compared with those obtained using traditional auscultation techniques. Furthermore, the PICUS system allows for two additional types of analysis: one based on the spectral energy distribution of the reflected signal (Wr) [2], and the based on the calculation of the Impact Time (IT) [3]. Both methods assign the output result to the Z coordinate.…”

A portable and autonomous system for the diagnosis of the structural health of cultural heritage (PICUS)

“…Some solutions to the problem mentioned earlier are given in the literature. The most promising methodologies are the non-invasive investigations based on the extent of the cover's surface vibrations, using different techniques both to excite surfaces, and to measure a signal of interest [1][2][3][4][5]. Our method is based on the technique used by professional restorers.…”