1,721,048 research outputs found
Infrared vision inspection of cultural heritage objects from the city of L’Aquila, Italy and its surroundings
No full textThe city of L'Aquila, Italy has a long history of catastrophic earthquakes. The most recent devastating earthquake that caused enormous damage hit the city in April 2009. The city is also the home of a rich collection of artworks from the Romanesque, Gothic, Baroque and Renaissance periods. Cultural heritage in L'Aquila is undeniable, and the use of nondestructive testing techniques is fundamental for assuring the integrity of these valuable objects. The goal of this study was to assess the performance of infrared vision techniques for the inspection of cultural heritage objects from L'Aquila. Furthermore, processing techniques were also employed for image segmentation
Multi-scale contrast-to-noise ratio (MS-CNR): a novel metric for quantitative defect characterisation without manual region specification
No full textSpanish National Program for Mobility of Professors and Researchers [PRX22/00165]; Spanish National Plan for Scientific and Technical Research and Innovation [PID2021-124383OB-I00
Basalt fibre laminates non- destructively inspected after low- velocity impacts
Full text linkIn this work, the use of advanced thermographic techniques for the post-impact defect detection in basalt fibre reinforced composite laminates was investigated. The laminates were previously impacted at different energies, namely 7.5, 15 and 22.5 J and then subjected to accelerated environmental aging or to a coating process in order to conceal the previous damage due to low velocity impact. In both cases the defects could be identified using infrared thermography in the mid-wave infrared (MWIR) spectrum even after the treatments. In addition, short-wave infrared (SWIR) results were employed with the aim to clearly identify unsuspected resin-rich areas. Therefore, the non-thermal part of the infrared spectrum (SWIR) can be coupled with the thermal part (MWIR) providing a complete infrared vision beyond what is perceptible to the naked eye, i.e., in the visible spectrum
Subsurface defect characterization in artworks by quantitative PPT and holographic interferometry
No full textSubsurface defect characterization in artworks by quantitative PPT and holographic interferometry
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From the experimental simulation to integrated non-destructive analysis by means of optical and infrared techniques: results compared
No full textIn this work the possibility of modeling manufacturing ceramic products is analyzed through the application of transient thermography, holographic interferometry and digital speckle photography, in order to identify the subsurface defects characteristics. This integrated method could be used to understand the nature of heterogeneous materials (such as plastic, sponge simulating a void, wood, aluminum) potentially contained within ceramic materials, as well as to predict crack formation due to them. The paper presents the analysis of green ceramic tile containing defects of different types and sizes located at different depths. The finite element method is used for solving the problem of transient heat transfer occurring in experimental conditions. Unknown parameters of the numerical model (such as convective heat transfer coefficients and sample surface emissivity) were adjusted to obtain numerical simulation results as close as possible to those obtained experimentally. Similarities and differences between experimental and simulated data are analyzed and discussed. Possibilities for improving the results and further developments are proposed
Multi-scale signal-to-noise driven fusion of post-processing sequences for enhanced defect detectability in active infrared thermography
Full text linkActive infrared thermography has emerged as a crucial tool in non-destructive testing, providing real-time visual representations of thermal patterns on material surfaces. However, detecting and analyzing defects can be challenging due to noise interference, the lack of standardization in post-processing techniques, complexity in data analysis, variability in defect visibility across frames, and the influence of environmental factors. To address these limitations, this study proposes a novel approach that enhances defect detectability by fusing multiple sequences derived from various post-processing methods into single, interpretable images. The proposed approach employs a multi-scale signal-to-noise ratio metric to accurately identify regions of interest and determine the optimal time at which defect detectability is maximized. Validation with two composite specimens featuring diverse defect characteristics demonstrates the capability of the method to simplify analysis and reliably improve detection performance. Compared with wavelet-based image fusion, the proposed approach achieves superior defect visibility and clarity, demonstrating a significant advancement in the effectiveness and reliability of thermographic inspections
Discovering the mysteries of Santa Maria di Collemaggio Church (L’Aquila, Italy) by non-destructive testing techniques
No full textThe use of optical and infrared techniques for the restoration of the frescoes damaged by the earthquake. A case study: the fresco of Giacomo Farelli in the Church of Santa Maria della Croce di Roio (L’Aquila, Italy)
No full textThe 2009 L’Aquila earthquake occurred in the region of Abruzzo, in central
Italy. The main shock was rated 6.3 on the moment magnitude scale; its
epicentre was near L’Aquila, the capital of Abruzzo. Earthquakes mark the
history of L’Aquila, a city built on the bed of an ancient lake: the city was struck
in 1315, 1349, 1452, 1501, 1646, 1703, and 1706. Some of its most revered
buildings were badly affected by the earthquake. Among them there is the Santa
Maria della Croce di Roio Church, built in 1625, expanding a small chapel
(1221) dedicated to St. Leonard. The cycle of frescoes by Giacomo Farelli at this
Church expresses aspects of Marian devotion of its time. The object of our study
is a Farelli’s fresco that represents the discovery of the Statue of Our Lady. The
non-destructive testing prior to the earthquake of 2009, made by ESPI technique
before and after restoration, and the thermographic testing following the
earthquake, clearly identified a weakness of the structure, where the old
subsurface cracks and detachments are once again evident. The thermographic
image processing allowed us to identify the buried architectural structure.
Keywords: ESPI, IRT, fresco, earthquake, restoration
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