Abstract: In recent years, 3D media have become more and more widespread and have been made available in numerous online repositories. A systematic and formal approach for representing andorganizing shape-related information is needed to share 3D media, to communicate the knowledgeassociated to shape modelling processes and to facilitate its reuse in useful cross-domain usage scenarios. In this paper we present an initial attempt to formalize an ontology for digital shapes, called the Common Shape Ontology (CSO). We discuss about the rationale, the requirements and the scope of this ontology, we present in detail its structure and describe the most relevant choices related to its development. Finally, we show how the CSO conceptualization is used in domainspecific
application scenarios.
Abstract: This paper presents a system for the three-dimensional (3D) reconstruction of an underwater environment on the basis of multiple range views from an acoustical camera. The challenge is to provide the reconstruction on-line, as the range views are obtained from the sensor. The final target of the work is to improve the understanding of a human operator driving an underwater Remotely Operated Vehicle. The acoustic camera provides a sequence of 3D images in real time. Data must be registered and fused to generate a unique 3D mosaic in the form of a triangle mesh, which is rendered through a graphical interface. Available technologies for registration and meshing have been modified and extended to match time constraints. Some experiments on real data are reported.
Notes: Special issue on European projects on visual representation systems and services
Abstract: Extensible Markup Language (XML) is a meta-language for defining new languages. Its impact on the modern and emerging web technologies has been (and will be) incredible and it has represented the foundation of a multitude of applications. This chapter is devoted to the presentation of XML and its applications. It provides an introduction to this wide topic, covering the principal arguments and providing references and examples.
Abstract: We consider the problem of extracting morphology of a terrain represented as a Triangulated Irregular Network (TIN). We propose a new algorithm and compare it with representative algorithms of the main approaches existing in the literature to this problem. The new algorithm has the advantage of being simple, using only comparisons (and no floating-point computations), and of being suitable for an extension to higher dimensions. Our experiments consider both real data and artificial test data. We evaluate the difference in the results produced on the same terrain data, as well as the impact of resolution level on such a difference, by considering representations of the same terrain at different resolutions.
Abstract: 3D objects have become widely available and used in different application domains. Thus, it is becoming fundamental to use, integrate and develop techniques for extracting and maintaining their embedded knowledge. These techniques should be encapsulated in portable and intelligent systems able to semantically annotate the 3D object models in order to improve their usability and indexing, especially in innovative web cooperative environments. Lately, we are moving in this direction, with the definition and development of data structures, methods and interfaces for structuring and semantically annotating 3D complex models (and scenes) - even changing in time - according to ontology-driven metadata and following ontology-driven processes. Here, we concentrate on the tools for segmenting manifold 3D models and on the underline structural representation that we build and manipulate. We also describe the first prototype of an annotation tool which allows a hierarchical semantic-driven tagging of the segmented model and provides an interface from which the user can inspect and browse the entire segmentation graph.
Abstract: We consider the problem of representing and extracting morphological information from scalar fields. We focus on the analysis and comparison of algorithms for morphological representation of both 2D and 3D scalar fields. We review algorithms which compute a decomposition of the domain of a scalar field into a Morse and Morse-Smale complex and algorithms which compute a topological representation of the level sets of a scalar field, called a contour tree. Extensions of the morphological representations discussed in the chapter are briefly discussed.
Abstract: In the last few years, the volume of multimedia content available on the Web significantly increased. This led to the need for techniques to handle such data. In this context, we see a growing interest in considering the Semantic Web in action and in the definition of tools capable of analyzing and organizing digital shape models. In this paper, we present a Semantic Web environment, be-SMART, for inspecting 3D shapes and for structuring and annotating such shapes according to ontology-driven metadata. Specifically, we describe in details the first module of be-SMART, the Geometry and Topology Analyzer, and the algorithms we have developed for extracting geometrical and topological information from 3D shapes. We also describe the second module, the Topological Decomposer, which produces a graph-based representation of the decomposition of the shape into manifold components. This is successively modified by the third and the fourth modules, which perform the automatic and manual segmentation of the manifold parts.
Abstract: Mesh-based terrain representations provide accurate descriptions of a terrain, but fail in capturing its morphological structure. The morphology of a terrain is defined by its critical points and by the critical lines joining them, which form a so-called surface network. Because of the large size of current terrain data sets, a multi-resolution representation of the terrain morphology is crucial. Here, we address the problem of representing the morphology of a terrain at different resolutions. The basis of the multi-resolution terrain model, that we call a Multi-resolution Surface Network (MSN), is a generalization operator on a surface network, which produces a simplified representation incrementally. An MSN is combined with a multi-resolution mesh-based terrain model, which encompasses the terrain morphology at different resolutions. We show how variable-resolution representations can be extracted from an MSN, and we present also an implementation of an MSN in a compact encoding data structure.
Abstract: In this paper, we describe, analyze and compare techniques for extracting spatial knowledge from a terrain model. Specifically, we investigate techniques for extracting a morphological representation from a terrain model based on an approximation of a Morse-Smale complex. A Morse-Smale complex defines a decomposition of a topographic surface into regions with vertices at the critical points and bounded by integral lines which connect passes to pits and peaks. This provides a terrain representation which encompasses the knowledge on the salient characteristics of the terrain. We classify the various techniques for computing a Morse-Smale complexe based on the underlying terrain model, a Regular Square Grid (RSG) or a Triangulated Irregular Network (TIN), and based on the algorithmic approach they apply. Finally, we discuss hierarchical terrain representations based on a Morse-Smale decomposition.
Abstract: Knowledge related to Shape Modelling is multi-faceted because of the complexity and heterogeneity of the involved resources and because different applications may cast different semantics on them. A fast evolution of the field is now conditioned by how research teams will be able to communicate and share resources and knowledge. The field needs to be formalized in order to achieve a shared conceptualization accessible by the whole scientific community and eventually to ensure an actual exploitation of its knowledge within the Semantic Web. In this context, the main objective of the Network of Excellence AIM@SHAPE is twofold: on the one hand to devise tools to capture the implicit semantics of digital shapes, and on the other hand to encode and formalize the domain knowledge into context-dependent ontologies. The paper describes the first results in the direction of developing an ontology for shape acquisition and reconstruction and its effective use in the Digital Shape Workbench, a searching framework for sharing resources (shapes, tools and publications) and their related knowledge.
Abstract: In the paper, we present an application of Web3D technologies, X3D with X3DOM and HTML5, to enhance our e-learning platform DIEL. DIEL exploits the social translucence concept in order to create a virtual and dynamic learning space where avatars of community members can interact while implementing any social constructivist learning paradigm. While supporting collaborative learning communities, the addition of high-performance 3D graphics into a DIEL web page, without requiring any plug-in at client side, allows a complete and meaningful interaction with the e-learning services, that benefits the users' experience in the exploitation of proximity relationships with respect to other users and resources.
Abstract: The Alps of southeastern France, better known as the Valley of Marvels, hide an impressive collection of engravings, mostly visible on the rocks around Mount Bego, which are irreplaceable witnesses of what life of the people who created them looked like. This calls for immediate action on promoting the awareness of this cultural treasure, which is hardly accessible by interested common men, as well as on helping domain experts to analyze these engravings and share their understanding and theories about them with other experts and with the mass. In this position paper, we propose technologies and partially achieved results for preserving in digital form all kinds of available data about the region. The technology will allow domain experts to: (1) organize and structure
data into an existing collaborative tool set, (2) process them, (3) make assumptions about the way of life of the ancient people based on them, and (4) make the results of such activities available in form of 3D Virtual Worlds.
Abstract: In the paper, we present DIEL, an application that makes a mixed use of a number of multimedia sources to enrich a well-known elearning platform, Moodle. DIEL exploits the social translucence concept in order to create a virtual and dynamic learning space where community members can easily interact while implementing any social constructivist learning paradigm. Moreover, an audio-video chat is as well seamlessly integrated, to serve as an orthogonal support for collaboration, for "face-to-face-like" interactions. The combination of the two approaches benefits the users' experience in the exploitation of proximity relationships with respect to other users and resources, to simplify and stimulate collaborative activities.
Abstract: Models of 3D objects have become widely accessible in several disciplines within academia and industry, spanning from scientific visualization to entertainment. In the last few years, 3D models are often organized into digital libraries accessible over the network, and thus semantic annotation of such models becomes an important issue. A fundamental step in annotating a 3D model is to segment it into meaningful parts. In this work, we present a Java3D framework for inspecting and segmenting 3D objects represented in X3D format. In particular, we present a combination of segmentation and merging techniques for producing a feasible decomposition of the boundary of a 3D object. We represent such decomposition as a graph, that we call the segmentation graph which is the basis for semantic annotation. We describe also the interface we have developed to allow visualization and browsing of both the decomposition and the segmentation graph in order to understand the topological structure of the resulting decomposition.
Abstract: Shape inspection options in most of the current online shape repositories provide limited information on the shape of a desired model. In addition, stored models can be downloaded only at the original level of detail (LOD). In this paper, we present our application that combines remote interactive inspection of a digital shape with real-time simplification. Simplification is parameterised, is performed in real-time and the results are again available for inspection. We have embedded the application in a shape repository whereby, having found a suitable simplification, users can download the model at that LOD.
Abstract: This paper presents a system for registration of 3D sonar data sets based on the Echoscope 1600 3D sonar. Although a 3D sonar image provides instantaneous volumetric data sets, many applications require the data sets to be mosaic'ed into larger data sets. The lack of navigation and motion sensors being able to produce mosaics with accuracies comparable to the 3D sonar resolution necessitates the use of registration techniques. Techniques for filtering of 3D sonar data, mesh generation, registration and geometric fusion applied to both on-line and offline mosaicing will be discussed. On-line mosaicing is done at a rate of 5 to 10 data sets per second, a rate that is acceptable in most practical situations. The techniques will find a number of applications, such as scanning harbors and seabed for potentially dangerous objects as well as seabed surveys. As the registration provides the sensor position relative to an object, object related positioning and navigation is also feasible, either as a stand alone underwater navigation system or as a system that improves current techniques like LBL, SBL and others.
