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Maya Sun Simulation of Bosnian Gravestone Virtual Model
(The Eurographics Association, 2006) Rizvic, S.; Sadzak, A.; Avdagic, Z.; Chalmers, A.; S. Battiato and G. Gallo and F. Stanco
Bosnia and Herzegovina is very rich with cultural heritage sites. Perhaps the most famous of these are the stecaks; the monumental gravestones of Bosnian Heretic Christians. The orientation of the stecaks was important to the ancient Bosnians, Unfortunately, their orientation towards the sun has been changed when they were moved from their original locations to more secure sites at museums. This is particularly true of the stecak from Donje Zgosce, one of the most beautiful stecaks in B&H. Using high-fidelity graphics techniques we have created a detailed virtual reconstruction of this stecak and produced a sun simulation in Maya This enables archaeologists to be able to investigate the interaction of the light with the stecak s carvings as it may have appeared in 14th century.
DentroTrento: an Example of Application of Computer Graphics to the Evolution of the Archaeological Site of Tridentum
(The Eurographics Association, 2006) Piffer, S.; Conti, G.; Girardi, G.; Ucelli, G.; Amicis, R. De; S. Battiato and G. Gallo and F. Stanco
This paper illustrates the DentroTrento project, commissioned by the local authority for Cultural Heritage, which has lead to the creation of an edutainment system for the visitors of an archaeological site in the town of Trento. In particular, the aim of the project was to enhance the didactic and entertaining potential of a Roman archaeological site which is located between the Theatre s foundations through the development of a computer graphics-based application capable of high visual and emotional impact. This has been made possible through the creation of an interactive system where the virtual reconstruction becomes the main means of guiding the visitor through a virtual walk across time. The relevance of the work illustrated is underlined by the profile of the project and the nature and importance of the site, which is located underground below a square. In fact this circumstance does not let the visitor perceive the urban outline of the roman town nor it lets visitors fully perceive, through the use of traditional teaching material, the way of life typical of the time. The system proposed instead engages the visitor into a more exciting experience replicating, not only the architecture, but the way of life of the Roman town. The scope of the project together with the heterogeneity of the working team has required a rigorous approach to the management of the entire project.
Using Layout Profiles in MPE G-4 Hypervideo Presentation
(The Eurographics Association, 2006) Bue, A. Lo; S. Battiato and G. Gallo and F. Stanco
The definition of presentation layout, based on device and user features, can be useful to provide multidevices content adaptation capabilities for hypervideos presentations. We provide a possible approach of content adaptation through different devices using MPEG-4 as presentation framework. In particular, we focus on the use of adaptable interfaces in hypervideos presentations, separating layout information from media data. A possibility of adaptation comes from separation of media representation and audiovisual scene structure in MPEG-4. We describe an implementation of this approach through XMT-A language, defining two layout examples and denoting advantages and problems encountered.
An Experimental Setup to Evaluate the Performance of Tone Mapping Algorithms
(The Eurographics Association, 2006) Marsi, S.; Impoco, G.; Ukovich, A.; Ramponi, G.; S. Battiato and G. Gallo and F. Stanco
Many algorithms have been proposed in the literature to solve the problem of mapping tones from high dynamic range sources to low dynamics displays, while preserving the information conveyed by the original scene. Methods and tools to evaluate the performance of tone mapping algorithms are needed. Some experiments have recently been presented involving human observers. In this paper, we propose method not relying on human scoring. Wellilluminated reference pictures of challenging scenes are captured and used as references. Low-quality shots of the same scenes are enhanced using some tone mapping algorithms and the outcome is compared to the reference images using a standard colour distance measure. The results clearly favour the more sophisticated local methods.
Adaptive Frame Rate Up-conversion with Motion Extraction from 3D Space for 3D Graphic Pipelines
(The Eurographics Association, 2006) Falchetto, M.; Barone, M.; Pau, D.; S. Battiato and G. Gallo and F. Stanco
A novel 3D Graphic Pipeline for mobile handheld devices is introduced. It s able to achieve increased frame-rate at its output, high picture quality, improved temporal anti-aliasing, thanks to frame-rate upconversion algorithm based on primitive s motion extraction and efficient compensation. Classic rendering process doesn t exploit spatial and temporal coherence of the motion: each frame is rendered by using a lot of the pipeline resources inside geometry, rasteriser and fragment processing stages. Moreover each frame is computed independently from the temporal adjacent one with a brute force approach. Video based algorithms instead (e.g. MPEG type of processing), heavily exploit temporal, spatial and statistical coherency of the content being coded, relying on motion estimation to extract motion vectors from pixel domain during coding process and apply them during motion compensation decoding process. Previous works on 3D graphics were based on the use of impostors, sprite or coherent layers. Those approaches are too much complex and requires high computational power. Other ones based on frame averaging are too much simple: they achieve poor spatial and temporal quality and artifacts become clearly visible as the motion dynamic increases. Proposed approach instead exploits motion temporal coherency by extracting motion vectors from motions of visible primitives in screen space. Temporal coherence has been exploited between key frames using an adaptive motion compensated stage. This method is able to reconstruct the frames without introducing noticeable artifacts on final pictures. Results achieved are 10-15 dB better quality than simple temporal frame average and show a natural motion with no annoying artifacts like real video content shows.
Smart Ideas for Photomosaic Rendering
(The Eurographics Association, 2006) Blasi, G. Di; Gallo, G.; Petralia, M.P.; S. Battiato and G. Gallo and F. Stanco
Photomosaic is a technique which transforms an input image into a rectangular grid of thumbnail images preserving the overall appearance. The typical photomosaic algorithm searches from a large database of images one picture that approximates a block of pixels in the main image. Since the quality of the output depends on the size of the database, it turns out that the bottleneck in each photomosaic algorithm is the searching process. In this paper we present a technique to speed-up this critical phase using the Antipole Tree Data Structure. This improvement allows the use of larger databases without requiring much longer processing time, leading to very interesting results. Further we present some ideas to render an image in a "photomosaic style". These techniques are based on QuadTree and fractal images and allow the creation of very interesting "photomosaic effects".
Topological Descriptor for CAD Models with Inner Cavities
(The Eurographics Association, 2006) Symonova, O.; Dao, M.-S.; Amicis, R. De; Ucelli, G.; S. Battiato and G. Gallo and F. Stanco
The current work introduces an algorithm for constructing Reeb graph for CAD models and their inner cavities. The nodes of the graph represent areas of the manifold of the model where topological changes occur. Edges of the graph encode information about connections between such areas. The outline for the topological graph matching is given for detection of graph (sub)isomorphism. The proposed Reeb graph structure can be used as a descriptor of CAD models in the retrieval process.
Data-Driven Facial Feature Morphing for 3D Face Synthesis
(The Eurographics Association, 2006) Zhang, Yu; S. Battiato and G. Gallo and F. Stanco
This paper presents a data-driven method for synthesizing new realistic 3D human faces by morphing a set of facial features. The method takes as examples 3D scanned human face models in order to exploit the shape variations presented in the real faces of individuals. We automatically compute a vertex-to-vertex correspondence between the unregistered face scans by deforming a generic mesh to fit the specific person s face geometry in a global-tolocal fashion. Exploiting the statistics of the generated datasets of feature shapes we transform them into vector space representations by applying a principal component analysis (PCA). Our feature shape morphing model is formed as a linear combination of the main modes of feature shape variations. We introduce a shape smoothing and blending method for generating a seamlessly deformed mesh around the feature borders. We demonstrate our method by combining 3D morphing of four features to generate a wide range of different face shapes.
Tradition and Virtuality: The Caltagirone Staircase
(The Eurographics Association, 2006) Campisi, V.; Blasi, G. Di; Gallo, G.; S. Battiato and G. Gallo and F. Stanco
Computer Graphics (CG) and Virtual Reality (VR) are two of the most interesting research fields in Computer Science. In this paper we present an application of CG and VR in arts, tourist promotion and cultural heritage. We propose a technique able to simulate the Saint Mary of the Mount staircase, a magnificent staircase in Caltagirone, a beautiful baroque town in Sicily (Italy). Our system is an example of how new technologies may lead to a new way of interacting with traditional arts
SVG Vectorization by Statistical Region Merging
(The Eurographics Association, 2006) Battiato, S.; Farinella, G. M.; Puglisi, G.; S. Battiato and G. Gallo and F. Stanco
In this paper a novel algorithm for raster to vector conversion is presented. The technique is mainly devoted to vectorize digital picture maintaining an high degree of photorealistic appearance specifically addressed to the human visual system. The algorithm makes use of an advanced segmentation strategy based on statistical region analysis together with a few ad-hoc heuristics devoted to track boundaries of segmented regions. The final output is rendered by Standard Vector Graphics. Experimental results confirm the effectiveness of the proposed approach both in terms of perceived and measured quality. Moreover, the final overall size of the vectorized images outperforms existing methods.
Real-time Cataract Surgery Simulation for Training
(The Eurographics Association, 2006) Agus, M.; Gobbetti, E.; Pintore, G.; Zanetti, G.; Zorcolo, A.; S. Battiato and G. Gallo and F. Stanco
Cataract is a clouding of the eye's natural lens, normally due to natural aging changes, and involving at least half of the population over 65 years. Cataract extraction is the only solution for restoring a clear vision, and nowadays is probably the most frequently practiced surgical procedure. This paper describes a novel virtual reality simulation system for cataract surgery training, involving the capsulorhexis and phacoemulsification tasks. The simulator runs on a multiprocessing PC platform and provides realistic physically-based visual simulations of tools interactions. The current setup employs SensAble PHANToM for simulating the interaction devices, and a binocular display for presenting images to the user.
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. Stanco
These 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.
Designing a Virtual Reality Game for the CAVE
(The Eurographics Association, 2006) Livatino, S.; Agerbech, V.; Johansen, A.; Johansen, B.; S. Battiato and G. Gallo and F. Stanco
Virtual Reality has for many years been a technology which has stagnated in application and software development for games. The applications available for VR environments have increased but they mostly remain related to scientific purposes while computer games in VR are still being developed and only show a part of their actual potential. The game industry has begun to see the possibilities of VR games in a near future with the implementation of some popular games to a CAVE system. However, a full immersion VR solution still remains uncommon and expensive. This paper aims to demonstrate the potential of VR games, and in particular games for the CAVE, now that affordable solutions are close to reach as more powerful hardware is available at low price. The focus is also on the methodology to be pursued while designing a VR game. Results were encouraging and tests performed on a first prototype demonstrates system feasibility.
Sub-part correspondence using structure and geometry
(The Eurographics Association, 2006) Biasotti, S.; Marini, S.; S. Battiato and G. Gallo and F. Stanco
The paper describes a method for recognizing similar sub-parts of objects described by 3D polygonal meshes. The innovation of our method is the coupling of structure and geometry in the matching process. First of all, the structure of the shape is coded in a graph where each node is associated to a sub-part of the shape. Then, the matching between two shapes is approached using a graph-matching technique relying upon a geometric description of each sub-part.
Shape Reconstruction with Uncertainty
(The Eurographics Association, 2006) Papaleo, L.; Puppo, E.; S. Battiato and G. Gallo and F. Stanco
This paper presents a general Surface Reconstruction framework which encapsulates the uncertainty of the sampled data, making no assumption on the shape of the surface to be reconstructed. Starting from the input points (either points clouds or multiple range images), an Estimated Existence Function (EEF) is built which models the space in which the desired surface could exist and, by the extraction of EEF critical points, the surface is reconstructed. The final goal is the development of a generic framework able to adapt the result to different kinds of additional information coming from multiple sensors.
Compressed SVG Representation of Raster Images Vectorized by DDT Triangulation
(The Eurographics Association, 2006) Battiato, S.; Greco, F.; Nicotra, S.; S. Battiato and G. Gallo and F. Stanco
This paper presents a portable compression algorithm applied to raster data images properly triangulated by using DDT (Data Dependent Triangulation). In particular the input source data are encoded to be rendered by standard SVG (Scalable Vector Graphics) engine. The proposed compression strategy works reducing the overall entropy implementing some heuristic strategies to properly re-code the redundancy inside the mesh representation. The compressed data are enclosed into an SVG player able to both decompress and show the original image. Results show the effectiveness of the approach.
GPU based direct illuminance values computation for interactive lighting CAD
(The Eurographics Association, 2006) Selmo, D.; Musante, F.; Rossi, M.; S. Battiato and G. Gallo and F. Stanco
In this work we focus our attention on real-time direct illuminance values computation using dedicated 3D graphics hardware compatible with OpenGL 2 standard. Our method works with real light intensity distribution measured for lighting fixtures by enconding it in a texture for GPU data comunication. Illuminance values are reprensented in real-time by using a perceptual based colour scale. Illuminance computation is limited to direct light. This is not a severe limitation for exterior and road lighting design, and nevertheless it is a useful project parameter for interior lighting design too.
3D CT Segmentation for Clinical Evaluation of Knee Prosthesis Operations
(The Eurographics Association, 2006) Battiato, S.; Bosco, C.; Farinella, G. M.; Impoco, G.; S. Battiato and G. Gallo and F. Stanco
In surgical knee replacement, the damaged knee joint is replaced with artificial prostheses. An accurate clinical evaluation must be carried out before applying knee prostheses to ensure optimal outcome from surgical operations and to reduce the probability of having long-term problems. Useful information can be inferred from CT scans of the knee area, that can be used to estimate the stress that will be acting on the prosthesis being implanted. This information can be exploited to tailor the prothesis to the patient s anatomy. We present some ideas for a system intended to help surgeons in evaluating the post-operative outcome of knee prosthesis implantation. We also show some preliminary results about the 3D segmentation of CT data, that is the main activity of our lab in the project.
3D Input devices integration in CAD environment
(The Eurographics Association, 2006) Bruno, F.; Caruso, G.; Muzzupappa, M.; S. Battiato and G. Gallo and F. Stanco
Virtual Reality (VR) technologies are becoming commonly used tools in the product development process, starting from the styling review in the conceptual design phase, until to the Digital Mock-up (DMU) validation in the advanced stages of the design process. What has not yet been sufficiently investigated is the possibility to interact with the DMU directly inside the CAD environment using 3D input devices. Although few CAD systems, like CATIA V5, have an additional module to support VR devices, in most cases it is still necessary to customize the application to obtain the functionalities desired by the user. The present paper discusses difficulties and advantages related to the integration of VR techniques and 3D input devices in CAD systems. The work has been conducted analyzing and testing the potentialities of the Unigraphics NX3 CAD environment and implementing a software plug-in that allows the user to perform such interaction tasks employing 3D input devices.
Recovering 3D architectural information from dense digital models of buildings
(The Eurographics Association, 2006) Spinelli, A.; Ganovelli, F.; Montani, C.; Scopigno, R.; S. Battiato and G. Gallo and F. Stanco
In recent years the progress of 3D scanning technologies and the consequent growing commercialization of scanners opened a large spectrum of opportunities for many professionals. In particular, architects and engineers may access to a digital model of a building without having to model it using a CAD software. On the other hand, there are two important differences between the digitized and the handcrafted model. The first is the absence of interpretation. The digitized model is merely a set of polygons that describe, possibly in a very accurate manner, the scanned object. It does not provide the user with any other information about what a surface is (a wall, a window, an arch etc.) that, conversely, can be incorporated during the editing in a CAD session. The second difference is excess of realism. In the digitized models the are no planar walls, no right angles, no straight edges, simply because they are not, at the millimetric scale. Unfortunately, if a model must be used in a FEM simulation, for example, a CAD like model would be required. This paper describes an application framework and some techniques that have been implemented to help a non computer-graphics user in handling digital models of buildings acquired using 3D scanning. The techniques permit to visualize efficiently the models independently from their size, recover 3D information (measurements, sections, . . . ), extract geometric features and fit high level geometric primitives.

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