Cultural Heritage Artifacts Research Articles

The use of radiation in the study of cultural heritage artefacts

Patrons of art galleries and museums, tourists visiting historic buildings, and sightseers viewing archaeological sites are generally unaware of the extent to which science and technology has contributed to the value of what they see. Many countries rely on cultural tourism to generate national wealth. The use of radiation of many kinds to assist in the conservation/restoration of cultural heritage artefacts is described in this paper. In particular, the paper will describe studies of the pigments used in historic Australian Indigenous art, the degradation of manuscripts written using iron-gall inks, the protection of statues against corrosion and the selection of lubricants for use in old machinery.

Répertoire des techniques d’examen et d’analyse des œuvres du patrimoine culturel citées dans ce numéro

Répertoire des techniques d’examen et d’analyse des œuvres du patrimoine culturel citées dans ce numéro

Virtual reconstruction of archaeological heritage using a combination of photogrammetric techniques: Huaca Arco Iris, Chan Chan, Peru

Currently, the use of 3D digital acquisition techniques represents the most popular means for the documentation and digitization of archaeological heritage. The advantage of recreating a detailed virtual model of a site is twofold. On the one hand, it provides a support for archaeologists who deal with continuous work of restoration and their associated studies. In fact, the majority of the sites are made of perishable materials, making essential the adoption of fast tool for data acquisition. On the other hand, the different medium of visualization reaches the wider public directly, improving the spread of Cultural Heritage artefacts. The reality-based representation may not be sufficient by itself to convey all the information about a site. We therefore propose an integrated approach based upon a combination of different 3D acquisition techniques for virtual reconstruction of a complex archaeological building. In this paper, a methodology for a low cost acquisition, processing and visualization of data is presented. The aim of this work is to describe a complete workflow for virtual reconstruction, from the acquisition to the model visualization, by integrating spherical photogrammetry and dense reconstruction techniques. This allows one to obtain a model that is metrical and accurate at the same time. Details of the final virtual reconstruction demonstrate the validity of the pipeline. The methodology has been experimented on a typical building called Huaca Arco Iris, situated into the complex of Chan Chan site, an UNESCO archaeological area in Peru.

Modeling a virtual robotic system for automated 3D digitization of cultural heritage artifacts

Abstract Complete and detailed 3D scanning of cultural heritage artifacts is a still time-consuming process that requires skilled operators. Automating the digitization process is necessary to deal with the growing amount of artifacts available. It poses a challenging task because of the uniqueness and variety in size, shape and texture of these artifacts. Scanning devices have usually a limited focus or measurement volume and thus require precise positioning. We propose a robotic system for automated photogrammetric 3D reconstruction. It consists of a lightweight robotic arm with a mounted camera and a turntable for the artifact. In a virtual 3D environment, all relevant parts of the system are modeled and monitored. Here, camera views in position and orientation can be planned with respect to the depth of field of the camera, the size of the object and preferred coverage density. Given a desired view, solving inverse kinematics allows for collision-free and stable optimization of joint configurations and turntable rotation. We adopt the closed-loop inverse kinematics (CLIK) algorithm to solve the inverse kinematics on the basis of a particular definition of the orientation error. The design and parameters of the solver are described involving the option to shift the weighting between different parts of the objective function, such as precision or mechanical stability. We then use these kinematic solutions to perform the actual scanning of real objects. We conduct several tests with different kinds of objects showing reliable and sufficient results in positioning and safety. We present a visual comparison involving the real robotic system with its virtual environment demonstrating how view poses for different-sized objects are successfully planned, achieved and used for 3D reconstruction.

Developing 3D Imaging Programmes--Workflow and Quality Control

This article reports on a successful project for 3D imaging research, digital applications, and use of new technologies in the museum. The article will focus on the development and implementation of a viable workflow for the production of high-quality 3D models of museum objects, based on the 3D laser scanning and photogrammetry of selected ancient Egyptian artefacts. The development of a robust protocol for the complete process chain for imaging cultural heritage artefacts, from the acquisition of 2D and/or 3D images to the development of interactive applications for the public audience, was a specific objective of the project. The workflow devised by the university museum team combines reference photography and 3D imaging with a curatorial review of the actual object to its digital counterpart. It also integrates methodologies for managing the accompanying metadatasets to record these activities. As final stage deliverables from the process, the museum is making high-quality 3D images of artefacts from its collection available through creation and dissemination of digital 3D multiplatform interactive applications in order to allow remote access and to enhance the museum's public engagement. This short article concludes with practical considerations for a 3D imaging workflow such as time and skills needed, 3D model quality, and expectation management.

Programs for visualization, handling and quantification of PIXE maps at the AGLAE facility

The external beam setup of the AGLAE facility has been developed in order to combine PIXE with PIGE, EBS and recently IBIL for the analysis of cultural heritage artefacts. The upgraded external beam end-station integrates five large solid angle X-ray detectors either to reduce the risk of damage on sensitive artworks by decreasing the beam intensity or to routinely acquire elemental maps at various scales. While many programs are available to process PIXE maps acquired with nuclear microprobes, a software to process the major and trace elements PIXE maps point by point using GUPIX is not available. The present paper describes three programs developed for the AGLAE facility to process numerous maps obtained with multiple detectors. AGLAEMAP allows to handle maps and pixel groups within maps, TRAUPIXE to process quantitatively PIXE spectra of all pixels and DATAIMAGING to display the resulting quantitative elemental maps. The benefits of this software suite are demonstrated by processing a dataset acquired on a pellet of geostandard reference material and on a terre mêlée pottery shard sample created by the famous ceramist Bernard Palissy (1510–1589), highlighting chemical elements present in this polychrome ceramic.

PIXE analysis of historical paintings: Is the gain worth the risk?

The PIXE analysis of easel paintings constitutes a challenging task. Despite recognized merits and a few emblematic applications, PIXE has never been routinely applied to these fragile, complex and precious targets. The present work discusses the place of PIXE in the study of easel paintings and opens up perspectives for a more systematic usage of this analytical technique. Progress achieved since decades in the implementation of PIXE to study such fragile cultural heritage artefacts is reviewed, notably at the LABEC laboratory in Italy and at the AGLAE facility of the C2RMF in France. Two specific techniques developed for paintings are detailed and exemplified on Renaissance painting masterpieces: differential PIXE for paint layers depth profiling and multi-scale elemental mapping for the imaging of pigment distribution. Beam-induced damage, a major concern, notably depends on the employed beam fluence in particle/cm2 or μC/cm2. After recalling previous works on damage induced in chemical products comparable to pigments, we present the behaviour under different fluences of protons of a few MeV (1–300μC/cm2) of targets having high resemblance to historical easel paintings: pellets of specially synthesized lead white pigments, layers of lead white mixed with linseed oil and areas containing lead white of two 19th century paintworks. The results shed new lights on the behaviour of paintworks under the beam and pave the way to strategies for damage mitigation. In particular, the lowering of PIXE performance induced by the decrease of the beam fluence sets a trade-off between risk of damage and gained information which also impacts the PIXE scanning protocol for paintings. As an illustration of an adequate adjustment of this balance, we report the exploratory application of PIXE mapping to a large area of a 19th century easel painting without damage. The recorded elemental maps are compared to elemental maps collected on the same area using laboratory-based scanning XRF.

Statistical analysis of engraving traces on a 3D digital model of prehistoric stone stelae

Studying cultural heritage artefacts, using 3D digital models, is gaining interest. It not only allows applications in documentation and visualisation, but also permits further contact-less examination. In this paper, we are presenting a statistical analysis of stone engravings based on features that were semi-automatically extracted from 3D acquisition data. Our objects of study are two Neolithic stone stelae and a faithful replica that was created in the course of an archaeological study. We use common statistical methods and investigate the populations of depth and diameter of the engraving traces, as well as their correlation. We observe that the erosion of the two prehistoric stelae results in a larger dispersion of the diameter distribution, as well as in a similarity of a linear regression model. Furthermore, we note a similar median in the height and depth distribution between the replica and only one of the prehistoric stela. This finding supports an archaeological hypothesis regarding the presumed engraving tools.

3D Visualization of Cultural Heritage Artefacts with Virtual Reality devices

Abstract. Although 3D models are useful to preserve the information about historical artefacts, the potential of these digital contents are not fully accomplished until they are not used to interactively communicate their significance to non-specialists. Starting from this consideration, a new way to provide museum visitors with more information was investigated. The research is aimed at valorising and making more accessible the Egyptian funeral objects exhibited in the Sforza Castle in Milan. The results of the research will be used for the renewal of the current exhibition, at the Archaeological Museum in Milan, by making it more attractive. A 3D virtual interactive scenario regarding the “path of the dead”, an important ritual in ancient Egypt, was realized to augment the experience and the comprehension of the public through interactivity. Four important artefacts were considered for this scope: two ushabty, a wooden sarcophagus and a heart scarab. The scenario was realized by integrating low-cost Virtual Reality technologies, as the Oculus Rift DK2 and the Leap Motion controller, and implementing a specific software by using Unity. The 3D models were implemented by adding responsive points of interest in relation to important symbols or features of the artefact. This allows highlighting single parts of the artefact in order to better identify the hieroglyphs and provide their translation. The paper describes the process for optimizing the 3D models, the implementation of the interactive scenario and the results of some test that have been carried out in the lab.

Gold layers characterization by Ion Beam Analytical Techniques: from Semiconductors to cultural heritage artefacts

An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

3DHOP: 3D Heritage Online Presenter

3D Heritage Online Presenter (3DHOP) is a framework for the creation of advanced web-based visual presentations of high-resolution 3D content. 3DHOP has been designed to cope with the specific needs of the Cultural Heritage (CH) field. By using multiresolution encoding, it is able to efficiently stream high-resolution 3D models (such as the sampled models usually employed in CH applications); it provides a series of ready-to-use templates and examples tailored for the presentation of CH artifacts; it interconnects the 3D visualization with the rest of the webpage DOM, making it possible to create integrated presentations schemes (3D + multimedia). In its design and development, we paid particular attention to three factors: easiness of use, smooth learning curve and performances. Thanks to its modular nature and a declarative-like setup, it is easy to learn, configure, and customize at different levels, depending on the programming skills of the user. This allows people with different background to always obtain the required power and flexibility from the framework. 3DHOP is written in JavaScript and it is based on the SpiderGL library, which employs the WebGL subset of HTML5, implementing plugin-free 3D rendering on many web browsers. In this paper we present the capabilities and characteristics of the 3DHOP framework, using different examples based on concrete projects.

Anoxic treatment for the disinfestation of wood cultural heritage: assessment of the effects and harmfulness on different species

Wooden artefacts, wood painted panels and historic furniture represent a significant part of our cultural heritage. Their preservation over time is a challenging task, and insect infestation still represents a primary cause of loss of cultural heritage artefacts. Anoxic conditions have proved to be effective in pest control and have been extensively applied to the management of museum collections. The present work reports on the evaluation of the effects and harmfulness of nitrogen-based anoxic treatment on different wood species with or without superficial finishings. Specimens were prepared in order to be representative of various surfaces of cultural heritage objects. A complete monitoring of the treatment effects was performed by means of a multianalytical approach. FTIR spectroscopy in the MID-IR and NIR regions was conducted to assess the absence of chemical alterations, and the results were subjected to chemometric treatment by multivariate analysis. Colorimetric characterization of the surfaces was performed to monitor any undesired colour change induced by the conservation treatment. The absence of superficial mechanical damages was evaluated by means of optical and scanning electron microscopy. The results confirmed that the anoxic procedure is not harmful to the treated surfaces with respect to aesthetic, chemical and microstructural considerations, even when the most stressful conditions are applied. As wood permeability is an important parameter in order to plan an effective intervention, in this study, a simplified method to estimate the permeability of wood to oxygen in different conditions was tested.

Comparison of engagement and emotional responses of older and younger adults interacting with 3D cultural heritage artefacts on personal devices

The availability of advanced software and less expensive hardware allows museums to preserve and share artefacts digitally. As a result, museums are frequently making their collections accessible online as interactive, 3D models. This could lead to the unique situation of viewing the digital artefact before the physical artefact. Experiencing artefacts digitally outside of the museum on personal devices may affect the user's ability to emotionally connect to the artefacts. This study examines how two target populations of young adults (18–21 years) and the elderly (65 years and older) responded to seeing cultural heritage artefacts in three different modalities: augmented reality on a tablet, 3D models on a laptop, and then physical artefacts. Specifically, the time spent, enjoyment, and emotional responses were analysed. Results revealed that regardless of age, the digital modalities were enjoyable and encouraged emotional responses. Seeing the physical artefacts after the digital ones did not lessen their enjoyment or emotions felt. These findings aim to provide an insight into the effectiveness of 3D artefacts viewed on personal devices and artefacts shown outside of the museum for encouraging emotional responses from older and younger people.

Fully Automatic, Omnidirectional Acquisition of Geometry and Appearance in the Context of Cultural Heritage Preservation

Effective documentation and display of ancient objects is an essential task in the field of cultural heritage conservation. Digitization plays an important role in the process of creating, preserving, and accessing objects in digital space. Up to the present day, industrial scanners are used for this task, which focus mainly on the detailed reconstruction of the object’s geometry only. However, particularly important for a faithful digital presentation of the object is the appearance information—that is, a description of the used materials and how they interact with incident light. Using the world’s first full-spherical scanner, we propose a user-friendly reconstruction process that is specifically tailored to the needs of digitizing and representing cultural heritage artifacts. More precisely, our hardware specifically addresses the problem that invaluable or fragile artifacts may not be turned over during acquisition. Nevertheless, we can digitize the object completely, including its bottom. Further, by integrating appearance information into our digitization, we achieve a far more faithful digital replica with a quality comparable to a real picture of the object. But in contrast to a static picture, our representation allows one to interactively change the viewing and lighting directions freely. In addition, the results are very memory efficient, consuming only several megabytes per scanned object. In cooperation with museums and a private collector, we digitized several cultural heritage artifacts to demonstrate the feasibility of the proposed process.

Using a Combination of Micro--Computed Tomography, CAD and 3D Printing Techniques to Reconstruct Incomplete 19th-Century Cantonese Chess Pieces

As scanning technologies improve new approaches to digitizing cultural heritage artefacts emerge. The use of micro--computed tomography (micro-CT) presents an interesting approach as it is capable of high-resolution scans of not just the surface of the artifact but also the intricate internal structures and volumes leading to more complete digitization than is possible with traditional surface laser scanning techniques. In this work, we investigate the potential to digitize heritage artifacts using micro-CT and focus on the methods of interacting with the datasets to create digital restorations of broken and incomplete pieces before printing physical replicas using 3D printing technology. We visualize the virtual models with clear identification of the new portions added by a digital artist with reference to existing pieces and archives.

Materials Surface Science Applied to the Investigation of Cultural Heritage Artefacts

The skill of ancient artisans manufacturing artistic or everyday artworks surprises the modern material scientists. We show, through the study of archaeological pieces, how laboratory research instruments use enlightens the fabrication processes of unique items at antic periods. The specificity of surface science research favouring non-invasive means for investigations on museum objects is emphasised. The examples concern:- Nanostructured layers on ceramic surface to obtain the so-called lustre effect, invented by ancient Islam potters;- Intentional coloration of metallic objects by chemical patination, attested in Egypt on 2nd millenary BC and still applied by Japanese artisans;- The history of gilding objects: leaf gilding, mercury gilding, and other processes;- The Fresco technique, a perennial wall painting, known by ancient Roman and propagated through centuries.The examples open new fields belonging to the modern materials science, to understand the mechanism involved in processes with the constraint that one does not know all the fabrication steps.

Utilizing Multispectral Scanning and Augmented Reality for Enhancement and Visualization of the Wooden Sculpture Restoration Process

Abstract Nowadays the digitization of the cultural heritage artefacts utilizing 3D scanning (with RGB or multispectral textures) is broadly used. In our project AREST (Augmented reality and reconstruction in the restoration process) we want to create a full pipeline for producing 3D models of artefacts (wooden statues) in different stages of restoration and utilize them to present the restoration process in the comprehensive way to a broad public. To present the process, we propose a device called Virtual Vitrine which will combine the commercial passive stereo display with view dependent stereo and gesture interaction. An essential part of the project is also an acquisition of multispectral images (textures) of artefacts that can be analysed by professional conservators.

Imaging Sacred Artifacts: Ethics and the Digitizing of Lichfield Cathedral's St Chad Gospels

This essay examines complexities that attend digitizing a cultural heritage artifact that is sacred to a contemporary community. It argues that scholars must first determine how the artifact participates in the life of its community. If this participation is integral, scholars should treat the artifact as a present-day cultural phenomenon, inseparable from its community. To explain the implications of this shift, the author turns to ethnography, which has a lengthy tradition of interacting with communities for generating research. Photographing a sacred artifact is not unlike other ethnographic research, whether tape recording stories, collecting documents, or gathering information about social practices. To guide digital work, the essay proposes ethnographic ethical principles, demonstrating their value in digitizing the 8th-century St Chad Gospels at Lichfield Cathedral, England—supporting Jamie Bianco's recent call for an "ethical turn" in the digital humanities.

Digital Holographic Printing Methods for 3D Visualization of Cultural Heritage Artifacts

Holography enables capture and reconstruction of the optical field scattered from three-dimensional (3D) objects. The hologram encodes both amplitude and phase of the field under coherent illumination, whereas photography records only the amplitude by incoherent light. 3D visualization feature of holography motivates expansion of research efforts dedicated to digital holographic imaging methods as a holographic display or a holographic printer. The paper presents two holographic 3D printing techniques which combine digital 3D representation of an object with analog holographic recording. Generation of digital contents is considered for a holographic stereogram printer and a recently proposed wavefront printer. These imaging methods could be applied to specific artifacts which are difficult to be recorded by conventional analog holography.

Interpreting Metadata and Ontologies of Virtual Heritage Artefacts

Many cultural heritage artefacts are digitised, resulting in a considerable number of virtual heritage artefacts, including 3D models, textual database records, images, point clouds, videos and so forth. These virtual heritage artefacts are often, if not always, accompanied by metadata standards and commonly agreed upon ontologies. These metadata and ontologies allow to build representations of virtual heritage artefacts that can be shared afterwards across different environments. In other words, the information about the artefact is interoperable. In many cases, however, it appears to be not so straightforward to use the artefact information in a context different from what it was initially meant for. This situation is analysed here, indicating that the interpretation of artefacts, both virtual and real, depends not only on the observed entities (virtual and real artefacts), but also on the background knowledge of the interpreter (personal), which can only remotely be captured in metadata and ontologies (cfr. user profiles). From the analysis results, recommendations are proposed about the pragmatic usage of metadata and ontologies in the context of virtual heritage artefacts.