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Pula CA, Italy

Pintore G.,CRS4 Visual Computing | Gobbetti E.,CRS4 Visual Computing
Visual Computer | Year: 2014

We present a system to easily capture building interiors and automatically generate floor plans scaled to their metric dimensions. The proposed approach is able to manage scenes not necessarily limited to the Manhattan World assumption, exploiting the redundancy of the instruments commonly available on commodity smartphones, such as accelerometer, magnetometer and camera. Without specialized training or equipment, our system can produce a 2D floor plan and a representative 3D model of the scene accurate enough to be used for simulations and interactive applications. © 2014 Springer-Verlag Berlin Heidelberg. Source

Pintore G.,CRS4 Visual Computing | Agus M.,CRS4 Visual Computing | Gobbetti E.,CRS4 Visual Computing
Proceedings - 2014 International Conference on 3D Vision Workshops, 3DV 2014 | Year: 2014

We present a practical system to map and reconstruct multi-room indoor structures using the sensors commonly available in commodity smart phones. Our approach combines and extends state-of-the-art results to automatically generate floor plans scaled to real-world metric dimensions and to reconstruct scenes not necessarily limited to the Manhattan World assumption. In contrast to previous works, our method introduces an interactive method based on statistical indicators for refining wall orientations and a specialized merging algorithm for building the final rooms shape. The low CPU cost of the method makes it possible to support full execution by commodity smart phones, without the need of connecting them to a compute server. We demonstrate the effectiveness of our technique on a variety of multi-room indoor scenes, achieving remarkably better results than previous approaches. © 2014 IEEE. Source

Villanueva A.J.,CRS4 Visual Computing | Marton F.,CRS4 Visual Computing | Gobbetti E.,CRS4 Visual Computing
Proceedings - 20th ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games, I3D 2016 | Year: 2016

Voxelized representations of complex 3D scenes are widely used nowadays to accelerate visibility queries in many GPU rendering techniques. Since GPU memory is limited, it is important that these data structures can be kept within a strict memory budget. Recently, directed acyclic graphs (DAGs) have been successfully introduced to compress sparse voxel octrees (SVOs), but they are limited to sharing identical regions of space. In this paper, we show that a more efficient lossless compression of geometry can be achieved, while keeping the same visibility-query performance, by merging subtrees that are identical through a similarity transform, and by exploiting the skewed distribution of references to shared nodes to store child pointers using a variabile bit-rate encoding. We also describe how, by selecting plane reflections along the main grid directions as symmetry transforms, we can construct highly compressed GPU-friendly structures using a fully out-of-core method. Our results demonstrate that state-of-the-art compression and real-time tracing performance can be achieved on high-resolution voxelized representations of realworld scenes of very different characteristics, including large CAD models, 3D scans, and typical gaming models, leading, for instance, to real-time GPU in-core visualization with shading and shadows of the full Boeing 777 at sub-millimetric precision. © 2016 ACM. Source

Bettio F.,CRS4 Visual Computing | Pintus R.,CRS4 Visual Computing | Pintus R.,Yale University | Villanueva A.J.,CRS4 Visual Computing | And 3 more authors.
Journal of Computing and Cultural Heritage | Year: 2015

We propose an approach for improving the digitization of shape and color of 3D artworks in a cluttered environment using 3D laser scanning and flash photography. To separate clutter from acquired material, semiautomated methods are employed to generate masks used to segment the range maps and the color photographs. This approach allows the removal of unwanted 3D and color data prior to the integration of acquired data in a 3D model. Sharp shadows generated by flash acquisition are easily handled by this masking process, and color deviations introduced by the flash light are corrected at the color blending step by taking into account the geometry of the object. The approach has been evaluated in a large-scale acquisition campaign of the Mont'e Prama complex. This site contains an extraordinary collection of stone fragments from the Nuragic era, which depict small models of prehistoric nuraghe (cone-shaped stone towers), as well as larger-than-life archers, warriors, and boxers. The acquisition campaign has covered 37 statues mounted on metallic supports. Color and shape were acquired at a resolution of 0.25mm, which resulted in more than 6,200 range maps (about 1.3G valid samples) and 3,817 photographs. © 2015 ACM. Source

Rodriguez M.B.,CRS4 Visual Computing | Gobbetti E.,CRS4 Visual Computing | Marton F.,CRS4 Visual Computing | Tinti A.,CRS4 Visual Computing
Proceedings - Web3D 2013: 18th International Conference on 3D Web Technology | Year: 2013

We present a software architecture for distributing and rendering gigantic 3D triangle meshes on common handheld devices. Our approach copes with strong bandwidth and hardware capabilities limitations in terms with a compression-domain adaptive multiresolution rendering approach. The method uses a regular conformal hierarchy of tetrahedra to spatially partition the input 3D model and to arrange mesh fragments at different resolution. We create compact GPU-friendly representations of these fragments by constructing cache-coherent strips that index locally quantized vertex data, exploiting the bounding tetrahedron for creating local barycentic parametrization of the geometry. For the first time, this approach supports local quantization in a fully adaptive seamless 3D mesh structure. For web distribution, further compression is obtained by exploiting local data coherence for entropy coding. At run-time, mobile viewer applications adaptively refine a local multiresolution model maintained in a GPU by asynchronously loading from a web server the required fragments. CPU and GPU cooperate for decompression, and a shaded rendering of colored meshes is performed at interactive speed directly from an intermediate compact representation using only 8bytes/vertex, therefore coping with both memory and bandwidth limitations. The quality and performance of the approach is demonstrated with the interactive exploration of gigatriangle-sized models on common mobile platforms. Copyright © ACM 978-1-4503-2133-4/13/06 $15.00. Source

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