1,720,970 research outputs found
HoloLens 2 Spatial Mapping Capabilities in Vast Monumental Heritage Environments
Full text linkHoloLens 2 is a state-of-the-art of Mixed Reality device that can augment the natural environment with virtual content in the form of holograms. Spatial mapping is the capability of the device to scan the environment and provide the user with a detailed 3D mesh model representation of its surroundings. The device can place holograms about real-world objects, perform occlusions and simulate physical interactions only having the geometric knowledge of its operating environment. HoloLens 2 mapping capabilities have been extensively tested. Nevertheless, no test was performed on monumental heritage buildings, where dimensions far exceed the typical sensor working range of the device. The authors want to evaluate the capability of the device to map monumental spaces. In these environments, dimensions, repetition of elements and heterogeneity of areas provide a real challenge for out-of-the-box Microsoft localization and mapping algorithms. The test case will be Milan Cathedral, inside the research project to build an MR application to help and enhance the systematic and planned maintenance intervention and inspections. Mapping capabilities have been tested in very different spaces: i) the south nave; ii) the empty volumes between the internal vaults and the external roof ("Sordine"); iii) the narrow spiral staircase connecting the south nave with the roofs lower level
MIXED REALITY CONTENT ALIGNMENT IN MONUMENTAL ENVIRONMENTS
Full text linkMixed reality provides on-the-spot and real-time data access capabilities by making virtual models and information more intuitive and accessible. Furthermore, allowing the operator to perceive 3D as holograms would allow for a more natural and straightforward manipulation of the perceived 3D content by permitting the augmentation of real objects with various levels of data. This can be accomplished by appropriately registering and superimposing the presented 3D models with the surrounding environment. This work aims to provide a quantitative evaluation of HoloLens 2 capabilities in registering virtual content inside monumental spaces. Two different methodologies are evaluated: Vuforia image targets and Microsoft World Locking Tools (WLTs). Tests have been performed inside Milan Cathedral's monumental spaces. Here, ambience dimensions, single architectural element repetition and non-uniform lighting conditions push out-of-the-box methods to their limits. Results show that WLTs with their space pins API can correctly reference virtual content keeping deviations in the order of 15 cm coping with the scale error produced from sensors' drifts
Machine Learning Methods for UNESCO Chinese Heritage: Complexity and Comparisons
Full text linkRecent years have seen the investigation and 3D documentation of architectural heritage becoming more accessible. The digitalization process could be more efficient when artificial intelligence is used in processing point cloud models. This article investigates the use of machine learning classification algorithms and a Multi-Level Multi-Resolution (MLMR) methodology to classify two point cloud projects in China, Nanchan Ssu, and Fokuang Ssu. Performances of multiple algorithms and solutions are compared, proving the applicability of MLMR on the point clouds. The practices pointed out the significance of corresponding features to classification rules and a sound logic in designing a systematic label tree with hierarchical semantic meanings
Enhanced Interaction Experience for Holographic Visualization
Full text linkNowadays, holographic visualization pushes further the limits in exploring tri-dimensional digital con-tent. 3D models typically displayed through a computer screen now enter the real world as holograms. The Hologram Table allows users to visualize and manipulate huge 3D models as if they were in the space in front of them. Its use has already proved helpful for the virtual fruition and presentation of complex cultural heritage buildings and their design interventions, but it surely can do more. The work aims at exploring the possibility of expanding the capabilities of the Hologram Table interaction by developing a custom-designed experience to interact with 3D point cloud data coming from survey activity. The test case was the interesting building of the Santa Maria delle Grazie (Milan, Italy) basilica. Initial results are encouraging and show that the point model can be enriched with associated information and additional content (images and texts) available for holographic visualization
RAPID AND LOW-COST PHOTOGRAMMETRIC SURVEY OF HAZARDOUS SITES, FROM MEASUREMENTS TO VR DISSEMINATION
Full text linkIn the field of geomatics, the development of 3D surveying techniques that can produce dense point clouds and high-resolution three-dimensional models has opened the possibility of using these techniques to generate digital replicas of a given asset to be used in contexts of cultural promotion or entertainment.These non-traditional applications have been made easier by the spreading of low-cost but fast surveying techniques, allowing them to be used in contexts or projects with fewer resources. Close-range photogrammetry is nowadays the cheapest, most flexible, and fastest technique that can be used to produce high-resolution and high-quality digital copies of reality. In this paper, we present an application of the Ant3D multi-camera system, a novel photogrammetric device designed for the rapid 3D surveying of sites characterized by poor accessibility and narrow spaces. The paper describes the three-dimensional acquisition of underground tunnels in a hazardous abandoned mining site. The digitalisation work aims to create 3D models to be experienced safely in a virtual- or augmented- reality immersive navigation of the site for cultural promotion. A workflow is proposed to turn raw reality-based 3D models into refined and efficient 3D assets that can be exploited in a game engine. Applications for mobile devices, desktop, and VR headsets, using the produced 3D assets are described.</p
3D SURVEYING, SEMANTIC ENRICHMENT AND VIRTUAL ACCESS OF LARGE CULTURAL HERITAGE
Full text linkIn recent years, Artificial Intelligence (AI) methods for 3D point cloud classification has assumed an essential role in the heritage field. The association of semantic information to 3D representations became a valuable instrument for measurement, analysis, education or maintenance, in particular in the Cultural Heritage (CH) sector. Moreover, the recent availability and reliability of head-mounted displays and glasses are allowing extraordinary immersive virtual experiences. This paper presents an end-to-end framework to handle large and complex 3D point clouds, from acquisition to semantic segmentation and final access in a Mixed Reality (MR) environment. Three completely different heritage scenarios are considered: the Temple of Neptune in Paestum, the Milan Cathedral and a large portion of Bologna’s porticoes. Mixed Reality experiences are described and shown based on the Microsoft HoloLens 2 device. A video of the results is available at https://youtu.be/Kd_3s0tIX04
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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