Observed methods of cuneiform tablet reconstruction in virtual and real world environments

The reconstruction of fragmented artefacts is a tedious process that consumes many valuable work hours of scholars' time. We believe that such work can be made more efficient via new techniques in interactive virtual environments. The purpose of this research is to explore approaches to the reconstruction of cuneiform tablets in the real and virtual environment, and to address the potential barriers to virtual reconstruction of fragments. In this paper we present the results of an experiment exploring the reconstruction strategies employed by individual users working with tablet fragments in real and virtual environments. Our findings have identified physical factors that users find important to the reconstruction process and further explored the subjective usefulness of stereoscopic 3D in the reconstruction process. Our results, presented as dynamic graphs of interaction, compare the precise order of movement and rotation interactions, and the frequency of interaction achieved by successful and unsuccessful participants with some surprising insights. We present evidence that certain interaction styles and behaviours characterise success in the reconstruction process

A Photogrammetric Analysis of Cuneiform Tablets for the purpose of Digital Reconstruction

Despite the advances made in the recording and cataloguing of cuneiform tablets, there is still much work to be done in the field of cuneiform reconstruction. The processes employed to rebuild cuneiform fragments still rely on glue and putty, with manual matching of fragments from catalogues or individual collections. The reconstruction process is hindered by inadequate information about the size and shape of fragments, and the inaccessibility of the original fragments makes finding information difficult in some collections. Most catalogue data associated with cuneiform tablets concerns the content of the text, and not the physical appearance of complete or fragmented tablets. This paper shows how photogrammetric analysis of cuneiform tablets can be used to retrieve physical information directly from source materials without the risk of human error. An initial scan of 8000 images from the CDLI database has already revealed interesting new information about the tablets held in cuneiform archives, and offered new avenues for research within the cuneiform reconstruction process.IBM Visual and Spatial Technology Centre, Institute of Archaeology and Antiquity, University of Birmingham, Edgbaston, Birmingham, B15 2TT

Multi-Scale Integral Invariants for Robust Character Extraction from Irregular Polygon Mesh Data

Hunderttausende von antiken Dokumenten in Keilschrift befinden sich in Museen, und täglich werden weitere bei archäologischen Grabungen gefunden. Die Auswertung dieser Dokumente ist wesentlich für das Verständnis der Herkunft von Kultur, Gesetzgebung und Religion. Die Keilschrift ist eine Handschrift und wurde in den Jahrtausenden vor Christi Geburt im gesamten alten Orient benutzt. Der Name leitet sich von den keilförmigen Eindrücken eines Schreibgriffels in den weichen Beschreibstoff Ton ab. Das Anfertigen von Handzeichnungen und Transkriptionen dieser Tontafeln ist eine langwierige Aufgabe und verlangt nach Unterstützung mittels automatisierter rechnergestützter Verfahren. Das Ziel dieser Arbeit ist die präzise Extraktion von Schriftzeichen mit variablen Formen in 3D. Die für die Merkmalsextraktion aus 2D-Mannigfaltigkeiten in 3D entscheidenden Schritte sind Kantenerkennung und Segmentierung. Robuste Techniken in der Signalverarbeitung und dem Shape Matching benutzen hierfür Integralinvarianten in 2D. In aktuellen Arbeiten werden die Integralinvarianten grob geschätzt, um wenige prägnante Merkmale zu finden, mit denen sich zerbrochene 3D-Objekte zusammensetzen lassen. Mit dem Ziel der exakten Bestimmung der 3D-Formen von Zeichen, wurde die aus der Bildverarbeitung und Mustererkennung bekannte Verarbeitungskette an 3D-Modelle angepasst. Diese Modelle bestehen aus Millionen von Messpunkten, die mit optischen 3D-Scannern aufgenommen werden. Die Punkte approximieren Mannigfaltigkeiten durch ein irreguläres Dreiecksnetz. Verschiedene Typen von integralinvarianten Filtern in mehreren Skalen führen zu verschiedenen hochdimensionalen Merkmalsräumen. Faltungen und kombinierte Metriken werden auf die Merkmalsräume angewandt, um Zusammenhangskomponenten zu bestimmen. Diese Komponenten stellen die Zeichen genauer als die Messauflösung dar. Parallel zum Design der Algorithmen werden die Eigenschaften der verschiedenen Integralinvarianten analysiert. Die Interpretation der Filterergebnisse sind von großem Nutzen zur Bestimmung von robusten Krümmungsmaßen und zur Segmentierung. Die Extraktion von Keilschriftzeichen wird mit einer Voronoi basierten Berechnung von minimalen normalisierbaren Vektordarstellungen vervollständigt. Diese Darstellung ist eine wichtige Grundlage für die Paläographie. Weitere Abstraktion und Normalisierung der Darstellung führt zur Zeichenerkennung. Die Einbettung der Algorithmen in das neu entworfene mehrschichtige GigaMesh Software Framework erlaubt eine Vielzahl von Anwendungen. Die Algorithmen nutzen den Speicher effektiv und die Verarbeitungskette ist parallelisiert. Die konfigurierbare Verarbeitungskette hat nur einen relevanten Parameter, nämlich die maximale Größe der zu erwartenden Merkmale. Die vorgestellten Verfahren wurden an Hunderten von Keilschrifttafeln, so wie weiteren realen und synthetischen Objekten getestet.Repräsentative Ergebnisse sowie Aufwands- und Genauigkeitsabschätzung der Algorithmen werden gezeigt. Ein Ausblick auf künftige Erweiterungen und Integralinvarianten in höheren Dimensionen gegeben

Fotónica y tecnologías de la luz en conservación y restauración de patrimonio

Desde la invención del láser en 1960, su influencia en las más diversas áreas de la ciencia y de la tecnología ha sido permanente y decisiva. El desarrollo de técnicas láser ha permitido generar métodos e instrumentos de muy alta resolución y sensibilidad para obtener soluciones en los más variados campos del conocimiento, la industria y la producción. Uno de los ámbitos donde este impacto es creciente es el de la conservación y restauración de objetos de valor patrimonial. La aplicación del láser y de técnicas fotónicas en este campo, se ha concentrado básicamente en tres grandes áreas. Por un lado en tratamientos de limpieza y preservación de objetos. Por otro lado en el desarrollo y aplicación de técnicas para el diagnóstico de estado, la caracterización de materiales y la identificación y autenticación de piezas y finalmente el registro de imágenes y su procesamiento, especialmente en 3 dimensiones, para fines de documentación. En este trabajo se muestran ejemplos de estas aplicaciones desarrolladas en el Laboratorio de Ablación Limpieza y Restauración con Láser del CIOp, pionero en el país y en Latinoamérica en estas temáticas

The reconstruction of virtual cuneiform fragments in an online environment

Reducing the time spent by experts on the process of cuneiform fragment reconstruction means that more time can be spent on the translation and interpretation of the information that the cuneiform fragments contain. Modern computers and ancillary technologies such as 3D printing have the power to simplify the process of cuneiform reconstruction, and open up the field of reconstruction to non-experts through the use of virtual fragments and new reconstruction methods. In order for computers to be effective in this context, it is important to understand the current state of available technology, and to understand the behaviours and strategies of individuals attempting to reconstruct cuneiform fragments. This thesis presents the results of experiments to determine the behaviours and actions of participants reconstructing cuneiform tablets in the real and virtual world, and then assesses tools developed specifically to facilitate the virtual reconstruction process. The thesis also explores the contemporary and historical state of relevant technologies. The results of experiments show several interesting behaviours and strategies that participants use when reconstructing cuneiform fragments. The experiments include an analysis of the ratio between rotation and movement that show a significant difference between the actions of successful and unsuccessful participants, and an unexpected behaviour that the majority of participants adopted to work with the largest fragments first. It was also observed that the areas of the virtual workspace used by successful participants was different from the areas used by unsuccessful participants. The work further contributes to the field of reconstruction through the development of appropriate tools that have been experimentally proved to dramatically increase the number of potential joins that an individual is able to make over period of time

Relief extraction and editing

Bas-reliefs are widely used in the world around us, for example, on coinage, for branding products, and for sculptural decoration. Reverse engineering of reliefs–extracting existing reliefs from input surfaces–makes it possible to apply them to new items; relief editing tools allow modification of reverse-engineered reliefs. This paper presents a novel approach to relief extraction based on differential coordinates, which offers advantages of speed and precise extraction. It also gives the first method in the literature specifically designed for relief editing. The base surface is estimated using normal smoothing and Poisson reconstruction, allowing a relief (which may lie on a smooth or textured input surface) to be automatically extracted by height thresholding. We also provide a range of relief editing tools, also using differential coordinates, permitting both global transformations (translation, rotation, and scaling) of the whole relief, as well as local modifications to the relief. Our relief editing algorithm, unlike generic mesh editing algorithms, is specifically designed to preserve the geometric detail of the relief over the base surface. The effectiveness of our methods is demonstrated on various examples of real industrial interest

Writing Around the Ancient Mediterranean

Writing in the ancient Mediterranean existed against a backdrop of very high levels of interaction and contact. In the societies around its shores, writing was a dynamic practice that could serve many purposes – from a tool used by elites to control resources and establish their power bases to a symbol of local identity and a means of conveying complex information and ideas. This volume presents a group of papers by members of the Contexts of and Relations between Early Writing Systems (CREWS) research team and visiting fellows, offering a range of different perspectives and approaches to problems of writing in the ancient Mediterranean. They focus on practices, viewing writing as something that people do within a wider social and cultural context, and on adaptations, considering the ways in which writing changed and was changed by the people using it

Persistent Homology in Multivariate Data Visualization

Technological advances of recent years have changed the way research is done. When describing complex phenomena, it is now possible to measure and model a myriad of different aspects pertaining to them. This increasing number of variables, however, poses significant challenges for the visual analysis and interpretation of such multivariate data. Yet, the effective visualization of structures in multivariate data is of paramount importance for building models, forming hypotheses, and understanding intrinsic properties of the underlying phenomena. This thesis provides novel visualization techniques that advance the field of multivariate visual data analysis by helping represent and comprehend the structure of high-dimensional data. In contrast to approaches that focus on visualizing multivariate data directly or by means of their geometrical features, the methods developed in this thesis focus on their topological properties. More precisely, these methods provide structural descriptions that are driven by persistent homology, a technique from the emerging field of computational topology. Such descriptions are developed in two separate parts of this thesis. The first part deals with the qualitative visualization of topological features in multivariate data. It presents novel visualization methods that directly depict topological information, thus permitting the comparison of structural features in a qualitative manner. The techniques described in this part serve as low-dimensional representations that make the otherwise high-dimensional topological features accessible. We show how to integrate them into data analysis workflows based on clustering in order to obtain more information about the underlying data. The efficacy of such combined workflows is demonstrated by analysing complex multivariate data sets from cultural heritage and political science, for example, whose structures are hidden to common visualization techniques. The second part of this thesis is concerned with the quantitative visualization of topological features. It describes novel methods that measure different aspects of multivariate data in order to provide quantifiable information about them. Here, the topological characteristics serve as a feature descriptor. Using these descriptors, the visualization techniques in this part focus on augmenting and improving existing data analysis processes. Among others, they deal with the visualization of high-dimensional regression models, the visualization of errors in embeddings of multivariate data, as well as the assessment and visualization of the results of different clustering algorithms. All the methods presented in this thesis are evaluated and analysed on different data sets in order to show their robustness. This thesis demonstrates that the combination of geometrical and topological methods may support, complement, and surpass existing approaches for multivariate visual data analysis

Digitalización 3D para documentación de objetos patrimoniales e instalaciones de media art

En los últimos años el uso de tecnologías para la adquisición de imágenes en 3D ha ganado una mayor atención por parte de museos y arqueólogos. Por otra parte, las técnicas de registro 3D junto con tecnologías de telepresencia (Realidad Virtual) pueden hacer una contribución importante a la conservación de Media Art y el arte de Instalación. En Argentina, las técnicas de registro en 3D para documentación y conservación prácticamente no tienen antecedentes de desarrollo y/o aplicación en el ámbito de la conservación-restauración de bienes culturales. Los registros siguen siendo los tradicionales, fotografías y dibujos que, además, implican la manipulación continua de las piezas. Los museos argentinos no utilizan técnicas de adquisición y procesamiento de imágenes, ni mucho menos técnicas de realidad aumentada o realidad virtual para difundir sus colecciones o para que el público interactúe con ellas. En el presente trabajo se presenta por un lado el desarrollo y la implementación de las técnicas de registro 3D y se muestran ventajas y limitaciones de cada una de ellas para la documentación de objetos patrimoniales. Se discute además las posibilidades de las tecnologías de telepresencia para documentación de instalaciones de Media Art y se muestra su aplicación a una instalación de una artista argentina