CNR – Institute of Acoustics “O. M. CORBINO” Paola Calicchia: acoustic deviceacoustic energy absorption phenomena 2D3D acoustic mapslocalization characterization of detachments Among innovative portable technologies for NDT analysis and the diagnosis of degradation phenomena, the employment of a diagnostic device for the evaluation of the degradation of frescoes is proposed. The proposed tool is an acoustic device based on the acoustic energy absorption phenomena evaluation in heterogeneous structures, such as antique frescoes and mural paintings in general. It provides 2D and 3D acoustic maps for the localization and characterization of detachments, fractures and delaminations. This tool provides to restaurateur artists objective data in the following actions: Diagnosis Diagnosis of the degree of deterioration of mural paintings; Evaluation of consolidation works Evaluation of consolidation works based on purposely defined criteria; Time evolution monitoring Time evolution monitoring of detachments by means of periodic exams, integrated by correlation to environmental data. (G. B. Cannelli, P. Calicchia, Italian Patent N. RM 99 A000410; USA Patent US , European Patent EP B1") “MAINTENENCE OF THE CULTURAL HERITAGE CONSTRUCTIONS FROM THEIR COMPREHENSION AS A WHOLE” - MACH Second preparatory meeting of consortium partners OPD Lab Restauro 28 February 2007 AC oustic E nergy A bsorption D iagnostic D evice – ACEADD

2 28 feb 2007 P. Calicchia MACH DEVICE UNITS: (1) TRANSMITTING -RECEIVING UNIT (2) TRANSDUCERS CIRCUITRY (3) AUTOMATIC X-Y SCAN UNIT (4) REMOTE UNIT FOR DATA ACQUISITION, SIGNAL PROCESSING AND MOTION CONTROL AC oustic E nergy A bsorption D iagnostic D evice – ACEADD (1) (2) (3) (4) (1) TRANSMITTING -RECEIVING UNIT : SOURCE S (O.5  15) kHz SOURCE S (O.5  15) kHz MINIATURE WIDE BAND OMNI-DIRECTIONAL RECEIVER M (O.05  15) kHz MINIATURE WIDE BAND OMNI-DIRECTIONAL RECEIVER M (O.05  15) kHz IN CO-AXIAL CONFIGURATION AND NORMAL INCIDENCE GEOMETRY (4) ACQUISIZIONE E SIGNAL PROCESSING: MEASUREMENT OF ACOUSTIC PRESSURE P(t) AT RECEIVER MEASUREMENT OF ACOUSTIC PRESSURE P(t) AT RECEIVER (standard distance from the surface 30cm) P(t) PROCESSED BY MEANS OF CEPSTRUM ALGORITHM C(t) P(t) PROCESSED BY MEANS OF CEPSTRUM ALGORITHM C(t) FROM C(t) h(t-  ) IS OBTAINED FROM C(t) h(t-  ) IS OBTAINEDCEPSTRUM p(t) FFT P(  ) Ln|P(  )| 2 IFFT C(t) = C i (t)+(L 1 /L 2 ) h(t-  ) 2 matrices (n x m) h(t-  ) L=c  Absorption map Roughness map

3 28 feb 2007 P. Calicchia MACH 2-D ABSORPTION MAP threshold set at 30% Hor. Axis (cm) Vert. Axis (cm) Vert. Axis (cm) Hor. Axis (cm) (%) 0 10,00 20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 100,0 (mm) 0 3,500 7,000 10,50 14,00 17,50 21,00 24,50 28,00 31,50 35,00 ABSORPTION MAP max abs. 52% ROUGHNESS MAP max height 14 mm 2-D 3-D 2-D overlaying the fresco image ACEADD – Acoustic Images The device was tested on laboratory model realized by OPD and on real frescos OTHER ANALYSIS: MODAL ANALYSIS ALONG SPECIFIC LINES EVALUATION OF THE THEORETICAL MODEL FOR DETACHMENTS ACOUSTICAL BEHAVIOUR ANALYSIS OF CONSOLIDATION TREATMENTS

4 28 feb 2007 P. Calicchia MACH ACEADD – Available Scan units for in-situ measurements At present a linear scan unit and an X-Y scan unit are available

5 28 feb 2007 P. Calicchia MACH ACEADD – Acoustic Images Scope Development Development of the transmit-receiving unit (TRU): acoustic source and receiver implementation in order to realize a TRU of small size, miniaturizing single components and assembling them in a specific unit embedded in a portable device. Development of the ACEADD as a mobile compact system: Hardware development for signal generation and acquisition; Software for data acquisition, signal processing and acoustic image generation. Survey In situ measurements: Surveys included in MACH program and data analysis. Correlation analyses: Interpretation of ACEADD results based on correlation analyses with environmental data, simulated models and other NDT methodologies results obtained in the same site.

6 28 feb 2007 P. Calicchia MACH Casa Vasari in Florence Hor. Axis (cm) Vert. Axis (cm) Vert. Axis (cm) Hor. Axis (cm) (%) 0 10,00 20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 100,0 (mm) 0 3,500 7,000 10,50 14,00 17,50 21,00 24,50 28,00 31,50 35,00 AB 1081 PUNTI ACEADD – Acoustic Images (a)(b) 40% 60%

7 28 feb 2007 P. Calicchia MACH d ABSORPTION MAP max abs. 68% Modal Analysis ACEADD – Acoustic Images