Papers by Kostas Hatzigiannakis
Archaeopress Publishing Ltd eBooks, Nov 30, 2015
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EGU General Assembly Conference Abstracts, Apr 1, 2018
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Universitätsverlag Kiel | Kiel University Publishing eBooks, 2023
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Optics for Arts, Architecture, and Archaeology V, 2015
The abbey’s church of Chaalis, in the North of Paris, was founded by Louis VI as a Cistercian mon... more The abbey’s church of Chaalis, in the North of Paris, was founded by Louis VI as a Cistercian monastery on 10th January 1137. In 2013, in the frame the European Commission's 7th Framework Program project CHARISMA [grant agreement no. 228330] the chapel was used as a practical case-study for application of the work done in a task devoted to best practices in historical buildings and monuments. In the chapel, three areas were identified as relevant. The first area was used to make an exercise on diagnosis of the different deterioration patterns. The second area was used to analyze a restored area. The third one was selected to test some hypotheses on the possibility of using the portable instruments to answer some questions related to the deterioration problems. To inspect this area, different tools were used: -Visible fluorescence under UV, - THz system, - Stimulated Infra-Red Thermography, SIRT - Digital Holographic Speckle Pattern Interferometry, DHSPI - Condition report by conservator-restorer. The complementarity and synergy offered by the profitable use of the different integrated tools is clearly shown in this practical exercise.
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ERCIM News, 2017
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In the field of art conservation there is an increased demand for non destructive and non invasiv... more In the field of art conservation there is an increased demand for non destructive and non invasive techniques able to perform remote defect detection for structural evaluation of historical structures and works of art. The techniques must have some basic important characteristics as non destructivity, accuracy, repeatability and desired features as non contact, portability, resolution, broad range of applicability. The simulated infrared thermography (SIRT) and digital holographic speckle pattern interferometry (DHSPI) are systems discussed in detail elsewhere; in this paper have been used in combined testing on art related targets according to the above criteria. Results confirm the effectiveness of both techniques in the conservation field and examples are here in presented. Each system is thus described as individual method highlighting the advantages and limitations of each. The aim is to present the suitability and appropriateness for accurate defect mapping in structural docum...
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Communications in Computer and Information Science, 2019
Cultural Heritage (CH) outdoor monuments are susceptible to severe and extreme weather phenomena ... more Cultural Heritage (CH) outdoor monuments are susceptible to severe and extreme weather phenomena as a result of the climatic change. The prompt detection and analysis, as well as the continuous monitoring of weathering formations and deterioration products is thus crucial for their preservation and longevity.
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Journal of Cultural Heritage, 2017
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ABSTRACT Over time the materials which constitute our cultural heritage may slowly deteriorate in... more ABSTRACT Over time the materials which constitute our cultural heritage may slowly deteriorate in response to environmental factors. Detecting change and monitoring degradation is critical if pre- ventive conservation strategies are to be improved. Digital Holographic Speckle Pattern Interferometry (DHSPI) is based on the principles of holography and allows the detection of various minute defects or structural heterogeneities in surface movement in paintings. For example, cracking and delamina- tion of paint can give rise to changes in interoferometric pat- terns. The technique requires no direct contact with the paint surface and can be applied to monitor paintings in real time. Paintings on canvas supports are highly sensitive to RH changes and their slight but continuous movement is of particu- lar interest1. In this paper a specially developed portable instrument incor- porating holographic interferometry is described that records speckle patterns. Canvas samples have been thermally aged and as a result paint has become more brittle and prone to cracking on the flexible canvas. Within the laminar structure, comprising two or more paint layers over a canvas, tension and stress may develop between layers due to uneven shrinkage, and pre-existing cracks may extend. The DHSPI images ac- quired illustrate the potential of the device. Very few examina- tion methods are able to measure the rapid microscopic move- ment of the paint surface and thus DHSPI is uniquely suited to monitoring canvas paintings especially with regard to changes in RH and temperature. Furthermore, the technique can be employed to detect cracks and their propagation. 1.1
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Experimental Analysis of Nano and Engineering Materials and Structures, 2007
This is an introductory paper of a recent EC project dealing with research in cultural heritage a... more This is an introductory paper of a recent EC project dealing with research in cultural heritage and aiming to communicate new fields of application for optical metrology techniques. The project is in its initial state and more conclusive information is expected to be available at the time of the perspective conference. Nowadays safety, ethical, economical and security issues as well
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Heritage Science, 2017
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ERCIM News, 2017
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Strain
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Optics for Arts, Architecture, and Archaeology VI
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Scientific Reports, 2017
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Photoacoustic imaging reveals hidden underdrawings in paintings, 2017
A novel, non-invasive, imaging methodology, based on the photoacoustic effect, is introduced in t... more A novel, non-invasive, imaging methodology, based on the photoacoustic effect, is introduced in the context of artwork diagnostics with emphasis on the uncovering of hidden features such as underdrawings or original sketch lines in paintings. Photoacoustic microscopy, a rapidly growing imaging method widely employed in biomedical research, exploits the ultrasonic acoustic waves, generated by light from a pulsed or intensity modulated source interacting with a medium, to map the spatial distribution of absorbing components. Having over three orders of magnitude higher transmission through strongly scattering media, compared to light in the visible and near infrared, the photoacoustic signal offers substantially improved detection sensitivity and achieves excellent optical absorption contrast at high spatial resolution. Photoacoustic images, collected from miniature oil paintings on canvas, illuminated with a nanosecond pulsed Nd:YAG laser at 1064 nm on their reverse side, reveal clearly the presence of pencil sketch lines coated over by several paint layers, exceeding 0.5 mm in thickness. By adjusting the detection bandwidth of the optically induced ultrasonic waves, photoacoustic imaging can be used for looking into a broad variety of artefacts having diverse optical properties and geometrical profiles, such as manuscripts, glass objects, plastic modern art or even stone sculpture. Visible optical imaging, including optical microscopy, often enhanced with multi-spectral resolution, represents a powerful approach in the investigation of various types of artworks, particularly those bearing color such as easel or wall paintings and polychromies. Spectrally-resolved imaging enables mapping of different paints across the surface of a painting and in many cases the recovered spectral information leads to pigment identification. However, paintings typically consist of several successive strata of paint, which are optically opaque, primarily because of strong scattering arising from the pigment particles. As a result, visible optical imaging is rather limited to a superficial analysis and thus features, which have been painted over, and can be significant for evaluating the previous history of a painting or even the making of it, may escape detection. This problem is directly related to the nature of light transport through opaque media, which is governed by scattering and diffusion that scramble any spatial information the same way fog blurs our vision. Therefore, there is an evident need for the development of novel, high precision, non-destructive imaging tools that will surpass the limitations imposed by light scattering and hence, extend the depth from which accurate information can be extracted. In this context, a challenge art conservation scientists often face relates to the detection and mapping of under-drawings in paintings. Underdrawings typically represent the original rough sketch used by the artist to portray the theme of the painting and guide the development of the artwork. Such kind of preparatory sketching is generally applied directly on the prepared canvas using charcoal, graphite or carbon black paint. Unavoidably, the covering of the preliminary drawing with several layers of paint, obstructs locating and retrieving the information related to the initial part of the artistic process, namely the original sketch, and furthermore the degree to which the artist followed faithfully this sketch or introduced subsequent alterations in the artwork (penti-mento). Underdrawings or underpaintings have been of exceptional interest to scholars for long time, because they contain information about the working practice of a particular artist or workshop. More specifically, the non-destructive detection of such hidden features has the potential to shed light to the social, historical, geographical or even psychological framework of the artistic creation, providing thus invaluable knowledge not only to art historians, but also to cultural heritage scientists who are interested in the determination of artworks authenticity. It is worth mentioning that there are numerous bibliographical references stating case-studies of
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Heritage Science, Springer International Publishing, 2017
Due to their unique properties, laser and optical technologies hold today an important role in th... more Due to their unique properties, laser and optical technologies hold today an important role in the protection and study of Cultural Heritage, since they are used in a wide range of demanding analytical and diagnostic applications. Considering the rapid and vast technological development of their methodologies and tools, it is necessary to make this new knowledge more reachable and comprehensible to heritage scientists. Towards this end, a web-based knowledge platform (Polygnosis) (http://politeia.iesl.forth.gr/polygnosis/) was designed by the Institute of Computer Science (ICS) of FORTH concerning the state-of-the-art light and/or laser-based techniques, which have been developed at the Institute of Electronic Structure and Lasers (IESL) of FORTH, for advanced imaging, analysis and diagnosis of Cultural Heritage objects. This educational digital tool seeks to highlight the efficiency and potentials of modern optical and laser technologies in Cultural Heritage documentation, as well as, promote the dissemination and deeper understanding of their applications to conservators, archaeologists, art historians, material and laser scientists. " Polyg-nosis " represents accumulated knowledge regarding the selection of the diagnostic tool and the suggested methodology , with simultaneous display of examples of actual experimental procedures. The model relates those examples with the relevant terminology of the Thesaurus, the information about the object under examination and the metadata resulting from those experiments. 'Polygnosis' thesaurus is a semantically structured vocabulary organized by a faceted classification, which serves the educational needs of the system. The current study concerns the definition and classification of terms for the development of the semantically linked Thesaurus, as well as, the presentation and review of the knowledge platform, with emphasis on the supportive role of the thesaurus in such an educational resource.
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Papers by Kostas Hatzigiannakis
The web-based knowledge platform and thesaurus ‘Polygnosis’ (2015) was designed by the Institute of Computer Science (ICS-FORTH ) regarding laser investigation techniques for CH analysis and diagnosis that have been developed at the Institute of Electronic Structure and Lasers (IESL-FORTH). In archaeometric studies, professionals from various scientific disciplines, such as archaeologists, conservators, conservation scientists etc., are involved in the examination process and diagnosis of CH, each using their own specialized terminology.
‘Polygnosis’ thesaurus covers a broad range of concepts and is capable of relating a CH object (Material Objects Facet) with the laser-based methods that can most effectively examine it (Investigation Methods Facet), the features that can be detected on this object (Identifiable Features Facet), and the documentation resulting from the applied examination methods (Data Facet). Its contents are semantically organized and dynamically enriched.
To conclude, ‘Polygnosis’ thesaurus aims to create open channels for communication, link knowledge to action through the translation of events/phenomena, facilitate information flow and increase transparency by bringing all perspectives to the table, providing rules of conduct, and establishing criteria for decision-making and problem-solving. This study focuses on the evaluation and validation of the thesaurus and investigates its value on CH sustainability.