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A New Descreening Technique in the Frequency Domain
(The Eurographics Association, 2006) Battiato, S.; Stanco, F.; S. Battiato and G. Gallo and F. Stanco
In this paper a new algorithm to obtain a continuous tone image starting from a halftoned one is proposed. This descreening technique is based on Butterworth filtering in the frequency domain. It removes the pattern of the original screen leaving unchanged the colors in the image. The proposed algorithm ensures fast and effective results, and can be used also by non-qualified operators.
A Natural and Effective Calibration of the CyberGlove
(The Eurographics Association, 2006) Partipilo, S.; Felice, F. De; Renna, F.; Attolico, G.; Distante, A.; S. Battiato and G. Gallo and F. Stanco
This work addresses the calibration of the CyberGlove, a device which provides information about the position and attitude in space of all the components of the user hand in a haptic system for the fruition of digital 3D contents by blind people. A realistic haptic interaction requires a reliable detection of user movements and a good calibration of the device to account for size and articulation capability of the specific hand. At the same time the application of interest calls for a calibration procedure that should be executable in a natural and straightforward way by every user. The two methods provided by the CyberGlove software are not suitable for these purposes: one is very simple and fast but produces quite imprecise results while the other is effective and accurate but involves a complex and cumbersome trial-and-error process not suited for general users. The proposed method aims to reach satisfactory results using a intuitive and simple approach. The user is asked to assume with his hand several pre-defined poses, each supplying the sensors output associated to known joints angles. Combining these data with the constraints derived by the anatomical structure of the hand it is possible to evaluate the values of the two parameters, gain and offset, that drive the digitalization of the sensor output. This process, in spite of its simplicity, has provided satisfactory results in several experimental sessions, enabling a realistic and reliable mirroring of user movements in the virtual space.
Solutions to 3D Building Reconstruction from Photographs
(The Eurographics Association, 2006) Farinella, G. M.; Mattiolo, G.; S. Battiato and G. Gallo and F. Stanco
The 3D model reconstruction of buildings from uncalibrated photographs allows new useful Computer Graphics and Computer Vision applications. In this paper we survey some solutions proposed in literature and in commerce. The common and different methodology are reported and described. Finally we try to address the 3D reconstruction problem of architectural scenes presenting our solution: BolBol. We demonstrate our reconstruction process and some results obtained applying BolBol to the modeling of real buildings.
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".
A study on textures and their perceptual visual dimensions as application for flexible and effective scientific visualization
(The Eurographics Association, 2006) Taponecco, F.; S. Battiato and G. Gallo and F. Stanco
The use of textures is fundamental in several areas of Computer Graphics, Computer Vision and Image Processing. In this work, we focus on their main relevant attributes, in order to define and design textures as effective visual representations for use in scientific visualization. We concentrate on the problem of visualizing complex multivariate and multi-dimensional datasets as well as in synthesizing multi-fields and temporal evolution of vectorial datasets visualization. Textures features, such as directionality, color and shape are particularly suited for use in a synthesis algorithm, and they serve as effective seed primitives, which can incorporate many visual dimensions for intuitive and flexible data mapping and encoding. As special application, we propose a level-based visualization approach, with a special focus on systematic layering of information for scientific datasets.
From Skull to Face: an Improved Framework for Ethnically Faithful 3D Face Reconstruction
(The Eurographics Association, 2006) Abate, A. F.; Nappi, M.; Ricciardi, S.; Sabatino, G.; S. Battiato and G. Gallo and F. Stanco
3D imagery can be a useful tool for archaeologists and anthropologists committed to the study of ancient people, helping them to better visualize the results of their theories and findings. This paper presents a methodology to generate a tridimensional model of a compatible face from its skull, and is specifically aimed to archaeological/anthropological applications. The proposed approach to facial reconstruction, that relies on craniometrical analysis and content based image retrieval technology, has two main purposes: to achieve a more ethnically faithful reproduction of main facial features respect to other techniques based on statistical data, and to allow a plausible reproduction of important physiognomic features (such as eyes, nose, lips, ears and hairs) which can t be inferred from the skull. The facial reconstruction of a female subject found in the archaeological site of Murecine (Pompei) who found death during the volcanic eruption in 79 a. C. is presented as a case study.
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.
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.
Use of Shader Technology for Realistic Presentation of Train Prototypes in Virtual Reality
(The Eurographics Association, 2006) Gironimo, G. Di; Papa, S.; S. Battiato and G. Gallo and F. Stanco
The aim of the paper is to make up a virtual showroom and work-through of a train model in order to allow railway companies showing new trains prototypes, in phase of concept, and present their new design in more exhaustive way than simply technical documentation. The possibility of applying Virtual Reality (VR) methodologies to make a scene more realistic as possible is a great advantage for the effectiveness of the presentation, in order to increase their competitivity. Shader technology allows the programmers to have control over shape, appearance (such as colour, lighting, reflection) and animation of objects, in order to make very realistic real-time rendering. In the paper the authors describe the use of shader technology in Virtual Design 2 (VD2) for realistic presentation of train prototypes in VR. The software VD2 is an extensive tool that allows following many phases of product development, from the creation of showroom for realistic presentations supporting shader technology to the assembly simulation or ergonomics analysis. Moreover, the possibility of interfacing with a wide range of input/output devices and the possibility to access to the API made this software to be chosen for Virtual Reality applications in the VR laboratory of the Competence Center for the Qualification of Transportation Systems founded by Campania Region (www.centrodicompetenzatrasporti.unina.it).
Multi-Modal Presentation of Work of Arts in Virtual Reality with Simulation of Multi-Mirror Reflection
(The Eurographics Association, 2006) Livatino, S.; Cuciti, D.; Wojciechowki, A.; S. Battiato and G. Gallo and F. Stanco
The use of different media such as photography and virtual reality combined with different presentation modalities may provide a user with an extraordinary tool for exploration and appreciation of real work of art. This is especially important in case of time-spatial works-of-art where the problem of functionalities presentation becomes much more demanding. The possibility offered by latest graphics machines has attracted the interest of researchers to investigate this new area. The goal of the presented work is the creation of a multi-modal presentation of a piece of contemporary art, tightening the relation between computer graphics and arts. The focus is on an application that it is capable to cope in real-time with simulation of mirror reflections, including multi-reflections. The results were very encouraging which led to optimistic conclusions with a wide range of options for future works.
VTK4AR: An Object Oriented Framework for Scientific Visualization of CAE Data in Augmented Reality
(The Eurographics Association, 2006) Bruno, F.; Caruso, F.; Ferrise, F.; Muzzupappa, M.; S. Battiato and G. Gallo and F. Stanco
In the last ten years many Augmented Reality (AR) applications for Scientific Visualization have been developed, attesting the effectiveness of this technique for data visualization and interaction. In all these applications, a software framework for scientific visualization was used to process data to be visualized, while an AR system was employed to display these data within an AR context. Hence, everyone who intended to approach the development of such applications should become necessarily familiar with the scientific visualization framework and the augmented reality one. This is of course an hurdle for the applications development, and the idea behind this work is exactly to provide a software framework that simplifies the development of such applications. With this in mind, we extended an existing and powerful open source library for scientific visualization (VTK) with few but useful classes for the interfacing with an existing AR library (ARToolKit) to easily handle the video see-through and the video-tracking functionalities. The resulting software tool, called VTK4AR, can be considered as an all in one software framework specific for scientific visualization in AR. Moreover, since it is built on top of VTK, it will be possible to employ a wide range of visualization techniques in many application fields. In particular, it has been tested in two AR applications: one for displaying data relative to a CFD simulation of a flow past a helmet, and another for displaying the forming error obtained prototyping an ankle support with the incremental forming technique.
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.
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.
Shape Comparison and Deformation Analysis in Biomedical Applications
(The Eurographics Association, 2006) Colantonio, S.; Moroni, D.; Salvetti, O.; S. Battiato and G. Gallo and F. Stanco
In this paper, we present a method for comparing shapes and analyzing deformations of 3D image objects. This method is based on the definition of an object model based on multi-source 3D images. Elective application cases of the proposed method consist of the analysis of deformable anatomical structures, useful to support medical diagnosis in routine clinical practice. In particular, preliminary aspects are discussed of a study case regarding heart dynamics.
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.
Topological, Geometric and Structural Approaches to Enhance Shape Information
(The Eurographics Association, 2006) Attene, M.; Biasotti, S.; Mortara, M.; Patané, G.; Spagnuolo, M.; Falcidieno, B.; S. Battiato and G. Gallo and F. Stanco
Nowadays, the increasing power of hardware components has made available a huge amount of digital models, more and more complex and detailed, as needed in many innovative research fields such as medical imaging, entertainment, product modelling and design. In this scenario, both industry and academy feel an urgent need of tools to efficiently describe, recognise and retrieve shapes, which usually require to enhance the raw geometry with additional high-level shape information. Analyzing and enhancing geometry is the basis for an efficient understanding of shapes, and has been for many years one of the most challenging issues at IMATI-GE/CNR. Recent advances in the field of semantic-based knowledge systems dealing with multi-dimensional media boosted this research field significantly, and the Shape Modeling Group at IMATI-GE/CNR produced several innovative methods that are reviewed in this paper. Approaches are classified and described along with some results, and discussed with respect to applications. Open issues are outlined along with future research plans.
A Survey of Digital Mosaic Techniques
(The Eurographics Association, 2006) Battiato, S.; Blasi, G. Di; Farinella, G.M.; Gallo, G.; S. Battiato and G. Gallo and F. Stanco
Art often provides valuable hints for technological innovations especially in the field of Image Processing and Computer Graphics. In this paper we survey in an unified framework several methods to transform a raster input image into good quality mosaics. The common and different ideas among the methods are reported and described. Finally we try to address the evaluation problem of an NPR algorithm.
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.
Hand Made 3d Modelling for the Reconstructive Study of Temple C in Selinunte : Preliminary Results
(The Eurographics Association, 2006) Gabellone, F.; S. Battiato and G. Gallo and F. Stanco
This paper illustrates the preliminary results of the virtual reconstruction of temple C in Selinunte. The reconstruction was undertaken as part of the Land-Lab Project launched by the University of Lecce in 2003 for the promotion and appropriate exploitation of the cultural, historic, artistic and archaeological heritage of two Italian regions, Puglia and Sicily, using advanced technologies. The reconstruction of temple C was launched with the help of numerous experts in the field of surveying and representation, as well as art historians, archaeologists and architects, following a fully multidisciplinary approach. The reconstructive study was conducted in a 3D environment mainly using NURBS modelling, Subdivision Surfaces and sub-polygonal displacement. Our reconstructive approach, which might be defined numerical, makes it possible to recompose, at least in the initial phases of the work, all the surveyed architectural elements in accordance with a procedure based on digital anastylosis. The reconstruction of the monument represents a contribution to the study of Doric architecture in southern Italy conducted with the help of modern technologies.

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