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Item VCLab s Tools for 3D range data processing(The Eurographics Association, 2003) Callieri, M.; Cignoni, P.; Ganovelli, F.; Montani, C.; Pingi, P.; Scopigno, R.; David Arnold and Alan Chalmers and Franco NiccolucciPost-processing of 3D scanned data is still the bottleneck for a wider diffusion of this technology. In this paper we describe our second generation tools for processing 3D scanned data. In particular, our tools support: range maps alignment, range maps merge (or fusion), mesh simplification and color attribute management. This software package has been implemented by scratch and encompasses both up-to-date solutions and some original methods (merging, simplification, color management and, in part, alignment). The paper presents the architecture of the tools, the features supported and algorithms used; finally, an evaluation of its use in the framework of a complex acquisition in the Cultural Heritage domain (3D scanning of a bronze statue) is reported.Item Digital representation and multimodal presentation of archeological graffiti at Pompei(The Eurographics Association, 2004) Balzani, M.; Callieri, M.; Fabbri, M.; Fasano, A.; Montani, C.; Pingi, P.; Santopuoli, N.; Scopigno, R.; Uccelli, F.; Varone, A.; Y. Chrysanthou and K. Cain and N. Silberman and F. NiccolucciGraffiti is a special form of art which gives us important knowledge on culture and social life of a lost civilization. Unfortunately, they are usually engraved on soft and non durable materials. The project described here originated from the request for a new approach to the preservation, study and ubiquitous access to Pompei s graffiti. A multidisciplinary team was setup to design a new methodology to support the digital acquisition, the study and the presentation to the public of this peculiar type of Cultural Heritage. We have investigated the use of 3D scanning technologies and graphics modelling to produce accurate digital reconstructions and to enhance them for an improved readability. The specific issues have been considered and ad hoc solutions have been devised. In terms of presentation, we have provided both visual media (interactive visualization) and physical reproduction, obtained by adopting modern rapid reproduction techniques. The work described is a sort of preliminary feasibility study: we are now planning to apply this methodology on a much wider scale at Pompei.Item Easy Access to Huge 3D Models ofWorks of Art(The Eurographics Association, 2006) Callieri, M.; Ponchio, F.; Cignoni, P.; Scopigno, R.; S. Battiato and G. Gallo and F. StancoAutomatic shape acquisition technologies evolved rapidly in recent years, and huge mass of 3D data can be easily produced. The high accuracy of range scanning technology makes the Cultural Heritage domain one of the ideal fields of use of these devices. Given this particular application domain, two issues arise: how to visualize at interactive rates these complex data on commodity computers (both locally and on web), and how to improve the ease of use of the visualization tools (as potential users are often not expert with interactive graphics). We present a new visualization system designed to support easy implementation of multimedia kiosk for museums or expositions, which has also been extended to web-based usage. The system allows naive users to inspect a large complex 3D model at interactive frame rates on off-the-shelf PC s, presenting the 3D model and all the multimedia data that has been linked to selected points of its surface. A main goal in the design of the system was to provide the user with a very easy and natural interaction approach, based on a straightforward "point and click" metaphor. Visualization efficiency is obtained by adopting a continuous level-of-detail (LOD) representation, where on-line automatic selection of the best-fit level of detail (according to the current view frustum) is coupled with visibility culling and ready-to-render representation of the geometry.Item Effective Annotations Over 3D Models(© 2020 Eurographics ‐ The European Association for Computer Graphics and John Wiley & Sons Ltd, 2020) Ponchio, F.; Callieri, M.; Dellepiane, M.; Scopigno, R.; Benes, Bedrich and Hauser, HelwigAnnotation support in interactive systems is often considered a simple task by the CG community, since it entails the apparently easy selection of a region and its connection with some information. The reality appears more complex. The scope of this paper is two‐fold: first, to review the status of this domain, discussing and characterizing several approaches proposed in literature to manage annotations over geometric models; second, to present in detail an innovative solution proposed and assessed in the framework of Cultural Heritage (CH) applications, called . At the annotation definition stage uses 3D data to characterize the annotation region; subsequently, annotations are visualized by adopting a two‐pass rendering solution which uses stencil buffers, thus without introducing new geometric elements, changing the topology or duplicating geometry elements. It solves most of the issues that afflict the current state of the art, such as fragmentation, annotation transfer to multiple representations and multi‐resolution data encoding. The latter is a mandatory requirement to produce efficient web‐based systems. We implemented and we fully tested this approach in the framework of a complex system that supports the documentation of CH restoration projects.Item Techniques for Computer Assisted Surgery(The Eurographics Association, 2007) Turini, G.; Pietroni, N.; Ganovelli, F.; Scopigno, R.; Raffaele De Amicis and Giuseppe ContiIn the recent decades robotic and computer science have been gaining more and more relevance in all aspects of our lives. In surgery, for example, they gave birth to procedures that would be impossible to perform otherwise (e.g. tele-surgery, nano-surgery). On this regard, these applied sciences already play an important role in assisting the surgeon both in the operative room and as a support in the education of young surgeons, but much work has still to be done. This paper presents some research and applicative results on Computer Assisted Surgery achieved in the framework of Endocas, a newly founded Center of Excellence in Pisa: a method for segmentation of anatomic parts from 3D dataset able to recover shapes from noisy 3D dataset; a technique for simulating bone drilling using a adaptive decomposition of tetrahedral meshes; a new open source library to support the implementation of techniques for simulating deformable objects.Item Implementing Mesh-Based Approaches for Deformable Objects on GPU(The Eurographics Association, 2006) Ranzuglia, G.; Cignoni, P.; Ganovelli, F.; Scopigno, R.; S. Battiato and G. Gallo and F. StancoThese latest years witnessed an impressive improvement of graphics hardware both in terms of features and in terms of computational power. This improvement can be easily observed in computer games, where effects which, until few years ago, could only be achieved with expensive CPU computation are now shown interactively. Although the GPU has been designed for implementing graphics effects, it is still it basically a processing unit with its own memory, and, being specialized for algebraic tasks, supplies a number of floating point operations per second which is orders of magnitude greater than the CPU. This suggested to the graphics community that the GPU could also be used for general purpose computation and a number of papers have been published on how to hack the GPU to this target. Following this trend we propose a framework for using GPU for implementing techniques for deformable objects represented as generic meshes. The framework only assumes than the global computation is the union of local computations, which is true for all the explicit methods.Item Multiple Textures Stitching and Blending on 3D Objects(The Eurographics Association, 1999) Rocchini, C.; Cignoni, P.; Montani, C.; Scopigno, R.; Dani Lischinski and Greg Ward LarsonIn this paper we propose a new approach for mapping and blending textures on 3D geometries. The system starts from a 3D mesh which represents a real object and improves this model with pictorial detail. Texture detail is acquired via a common photographic process directly from the real object. These images are then registered and stitched on the 3D mesh, by integrating them into a single standard texture map. An optimal correspondence between regions of the 3D mesh and sections of the acquired images is built. Then, a new approach is proposed to produce a smooth join between different images that map on adjacent sections of the surface, based on texture blending. For each mesh face which is on the adjacency border between different observed images, a corresponding triangular texture patch is resampled as a weighted blend of the corresponding adjacent images sections. The accuracy of the resampling and blending process is improved by computing an accurate piecewise local registration of the original images with respect to the current face vertices. Examples of the results obtained with sample Cultural Heritage objects are presented and discussed.Item Reconstructing head models from photographs for individualized 3D-audio processing(The Eurographics Association and Blackwell Publishing Ltd, 2008) Dellepiane, M.; Pietroni, N.; Tsingos, N.; Asselot, M.; Scopigno, R.Visual fidelity and interactivity are the main goals in Computer Graphics research, but recently also audio is assuming an important role. Binaural rendering can provide extremely pleasing and realistic three-dimensional sound, but to achieve best results it s necessary either to measure or to estimate individual Head Related Transfer Function (HRTF). This function is strictly related to the peculiar features of ears and face of the listener. Recent sound scattering simulation techniques can calculate HRTF starting from an accurate 3D model of a human head. Hence, the use of binaural rendering on large scale (i.e. video games, entertainment) could depend on the possibility to produce a sufficiently accurate 3D model of a human head, starting from the smallest possible input. In this paper we present a completely automatic system, which produces a 3D model of a head starting from simple input data (five photos and some key-points indicated by user). The geometry is generated by extracting information from images and accordingly deforming a 3D dummy to reproduce user head features. The system proves to be fast, automatic, robust and reliable: geometric validation and preliminary assessments show that it can be accurate enough for HRTF calculation.Item Efficient Processing of 3D Scanned Models(The Eurographics Association, 2004) Scopigno, R.; Gershon Elber and Nicholas Patrikalakis and Pere BrunetThe construction of detailed and accurate 3D models is made easier by the increasing diffusion of automatic sampling devices (often called 3D scanners). These allow to build digital models of real 3D objects in a cost- and time-effective manner. The talk will present the capabilities of this technology focusing mainly on some issues which are preventing a wider use of this technology, such as for example the considerable user intervention required and the complexity of the models produced.Another emerging issue is how to support the visual presentation of the models (local or remote) with guaranteed interactive rendering and data protection. Some examples of the results of current projects, mainly in the Cultural Heritage field, will be shown.Item Ray-Casted BlockMaps for Large Urban Models Visualization(The Eurographics Association and Blackwell Publishing Ltd, 2007) Cignoni, P.; Di Benedetto, M.; Ganovelli, F.; Gobbetti, E.; Marton, F.; Scopigno, R.We introduce a GPU-friendly technique that efficiently exploits the highly structured nature of urban environments to ensure rendering quality and interactive performance of city exploration tasks. Central to our approach is a novel discrete representation, called BlockMap, for the efficient encoding and rendering of a small set of textured buildings far from the viewer. A BlockMap compactly represents a set of textured vertical prisms with a bounded on-screen footprint. BlockMaps are stored into small fixed size texture chunks and efficiently rendered through GPU raycasting. Blockmaps can be seamlessly integrated into hierarchical data structures for interactive rendering of large textured urban models. We illustrate an efficient output-sensitive framework in which a visibility-aware traversal of the hierarchy renders components close to the viewer with textured polygons and employs BlockMaps for far away geometry. Our approach provides a bounded size far distance representation of cities, naturally scales with the improving shader technology, and outperforms current state of the art approaches. Its efficiency and generality is demonstrated with the interactive exploration of a large textured model of the city of Paris on a commodity graphics platform.
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