Browsing by Author "Mortara, Michela"

Now showing 1 - 7 of 7
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    3D Modeling and Integration of Heterogeneous Geo-data
    (The Eurographics Association, 2021) Miola, Marianna; Cabiddu, Daniela; Pittaluga, Simone; Mortara, Michela; Vetuschi Zuccolini, Marino; Imitazione, Gianmario; Frosini, Patrizio and Giorgi, Daniela and Melzi, Simone and Rodolà, Emanuele
    This paper tackles the volumetric representation of geophysical and geotechnical data, gathered during exploration surveys of the subsoil. The creation of a 3D model as support to geological interpretation has to take into account the specificity of the diverse input data, that are heterogeneous. Some data are massive, but cover the domain unevenly, e.g., structured along dense differently spaced lines, while others are very sparse, e.g., borehole locations with soil sampling and CPTU (Piezocone Penetration Test) locations. In this work, we focus on the exploration and analysis of underwater deposits. After a discussion about the data typically acquired in an offshore campaign, we present an automatic process to generate the subsurfaces and volume defining an underground deposit, starting from the identification of relevant morphological features in seismic data. In particular, data simplification and refinement based on geostatistics have been applied to generate regular 2D meshes from strongly anisotropic data, in order to improve the quality of the final 3D tetrahedral mesh. Furthermore, we also use geostatistics to predict geotechnical parameters from local surveys and estimate their distribution on the whole domain: in this way the 3D model will include relevant geological features of the deposit and allow extrapolating different geotechnical information with associated uncertainty. The volume characterization and its 3D inspection will improve the structural and stratigraphic interpretation of deposits, to support geological analysis and planning of future engineering activities.
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    An Automatic Approach for the Classification of Ancient Clay Statuettes Based on Heads Features Recognition
    (The Eurographics Association, 2019) Scalas, Andreas; Vassallo, Valentina; Mortara, Michela; Spagnuolo, Michela; Hermon, Sorin; Rizvic, Selma and Rodriguez Echavarria, Karina
    In recent years, quantitative approaches based on mathematical theories and ICT tools, known under the terms of digital, computational, and virtual archaeology, are more and more involved in the traditional archaeological research. In this paper, we apply shape analysis techniques to 3D digital replicas of archaeological findings to support their interpretation. In particular, our study focuses on a collection of small terracotta figurines from the ancient sanctuary of Ayia Irini, Cyprus, and it aims at re-analysing the material utilising a quantitative approach. We experiment state of the art techniques (meshSIFT and DBSCAN) to cluster statuettes according to the similarity of their heads, to investigate their production process.
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    Challenges in the Digitisation of a High-reflective Artwork
    (The Eurographics Association, 2021) Catalano, Chiara Eva; Brunetto, Erika; Mortara, Michela; Pizzi, Corrado; Hulusic, Vedad and Chalmers, Alan
    In this paper we report about the photogrammetric acquisition and reconstruction of a contemporary artwork, performed by offthe- shelf software. The ceramic piece of art is "Il Libro d'Oro del Terzo Paradiso" ("The Golden Book of the Third Paradise") by Michelangelo Pistoletto, accessed and studied in the framework of a regional project. This artefact is particularly challenging. On the one hand, it is golden coated and, as such, highly reflective. Hence, images are likely to suffer from highlight spots, shadows or self-reflections, and the reconstructed point cloud is typically noisy. On the other hand, the object exhibits simple geometry, mainly composed of planar surfaces, and is highly symmetric; however, it possesses detail features and undercuts. The symmetric nature of the object and reflections misled the image alignment, and the noise in the data turned out to be of the same scale as the detail features. We will discuss all the steps of the process, aimed at obtaining a high quality and accurate 3D model using low-cost tools.
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    A First Step Towards Cage-based Deformation in Virtual Reality
    (The Eurographics Association, 2020) Scalas, Andreas; Zhu, Yuanju; Giannini, Franca; Lou, Ruding; Lupinetti, Katia; Monti, Marina; Mortara, Michela; Spagnuolo, Michela; Biasotti, Silvia and Pintus, Ruggero and Berretti, Stefano
    The advent of low cost technologies makes the use of immersive virtual environments more interesting for several application contexts. 3D models are largely used in such environments for providing feelings of immersion and presence in the virtual world. 3D models are normally defined in dedicated authoring tools and then adapted to be used in the virtual environments; thus, any change in the model requires to loop back to the authoring tool for performing the wished modification and the successive adaptation processes. The availability of shape modification capabilities within the virtual environment can avoid the above modification-adaptation loop. To this aim, we present our first step in the development of a 3D modelling system in Virtual Reality. The shape modification is achieved through a cage-based deformation approach, applied to semantically enriched meshes, carrying annotated meaningful regions, thus allowing the direct selection and editing of significant object parts.
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    Mobile Laser Scanning of Challenging Urban Sites: a Case Study in Matera
    (The Eurographics Association, 2022) Scalas, Andreas; Cabiddu, Daniela; Mortara, Michela; Pittaluga, Simone; Spagnuolo, Michela; Ponchio, Federico; Pintus, Ruggero
    The creation of 3D models of heritage and architectural sites requires proper technologies able to capture a wide area at fine geometric and appearance detail. In this paper we address the acquisition and digitization of three challenging Points of Interest in Matera, Italy. The sites, both outdoor and indoor, are characterised by limited accessibility, complex morphology and poor lighting conditions. We describe our experience with a portable, lightweight laser scanner, describing the planning, acquisition and post-processing phases, and providing some lessons learnt in order to achieve good results in terms of quality and resolution.
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    Semantic Segmentation of High-resolution Point Clouds Representing Urban Contexts
    (The Eurographics Association, 2023) Romanengo, Chiara; Cabiddu, Daniela; Pittaluga, Simone; Mortara, Michela; Banterle, Francesco; Caggianese, Giuseppe; Capece, Nicola; Erra, Ugo; Lupinetti, Katia; Manfredi, Gilda
    Point clouds are becoming an increasingly common digital representation of real-world objects, and they are particularly efficient when dealing with large-scale objects and/or when extremely high-resolution is required. The focus of our work is on the analysis, 3D feature extraction and semantic annotation of point clouds representing urban scenes, coming from various acquisition technologies, e.g., terrestrial (fixed or mobile) or aerial laser scanning or photogrammetry; the task is challenging, due to data dimensionality and noise. In particular, we present a pipeline to segment high-resolution point clouds representing urban environments into geometric primitives; we focus on planes, cylinders and spheres, which are the main features of buildings (walls, roofs, arches, ...) and ground surfaces (streets, pavements, platforms), and identify the unique parameters of each instance. This paper focuses on the semantic segmentation of buildings, but the approach is currently being generalised to manage extended urban areas. Given a dense point cloud representing a specific building, we firstly apply a binary space partitioning method to obtain small enough sub-clouds that can be processed. Then, a combination of the well-known RANSAC algorithm and a recognition method based on the Hough transform (HT) is applied to each sub-cloud to obtain a semantic segmentation into salient elements, like façades, walls and roofs. The parameters of primitive instances are saved as metadata to document the structural element of buildings for further thematic analyses, e.g., energy efficiency. We present a case study on the city of Catania, Italy, where two buildings of historical and artistic value have been digitized at very high resolution. Our approach is able to semantically segment these huge point clouds and it proves robust to uneven sampling density, input noise and outliers.
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    Shape Analysis Techniques for the Ayia Irini Case Study
    (The Eurographics Association, 2018) Scalas, Andreas; Vassallo, Valentina; Mortara, Michela; Spagnuolo, Michela; Hermon, Sorin; Sablatnig, Robert and Wimmer, Michael
    The typical approach for archaeological analysis is mainly qualitative and, as such, subjective. Even when some measures are reported in the documentation of artefacts, they are often approximate or ambiguous. Conversely, the quantitative approach is based on objective metrics to produce replicable results and, coupled with digital tools, can assist the qualitative analysis in archaological research with no risk of damage. In this paper, we present a geometric-quantitative approach for the analysis of archaeological finds and the preliminary results of an ongoing joint research project of two doctoral students within the frame of the EU GRAVITATE project.