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Item High Resolution Medical 3D Data Sets on Mobile Devices and WebGL(The Eurographics Association, 2012) Jimenez, Juan-Roberto; Noguera, Jose Maria; Isabel Navazo and Gustavo PatowNowadays, mobile devices and the web are being used to deliver 3D graphics to mass users. However, applications such as visualization of high resolution medical models are still impossible to handle in such platforms due to texture limitations, mainly the lack of 3D texture support. In this paper we propose a software architecture and a novel texture storage technique that overcome these limitations. In addition, our proposal allows us to adapt existing direct volume rendering techniques based on 3D textures to mobile devices and WebGL. Our experiments demonstrate the feasibility and validity of our proposal to render high resolution volumetric models on both platforms.Item Non-rigid 3D Faces Registration using Geodesic Distance Maps(The Eurographics Association, 2012) Gurguí, T.; Poveda, F.; Martí, E.; Isabel Navazo and Gustavo Patow3D facial mesh registration is a key step in 3D facial analisys. This process calculates a mapping between faces in order to put in correspondence each point of both faces. In this poster we introduce a new approach for 3D face registration based in geodesical distances and 2D non-rigid registration.Item From the Patient to the Surgery - A Complete Computer Vision and Graphics Process(The Eurographics Association, 2012) Martinez, A.; Jimenez, J.; Isabel Navazo and Gustavo PatowGenerating digital information ready to use on a surgery operation from a patient is a complex process. This process involves computer vision techniques, in order to extract digital information from medical images, and computer graphics techniques in order to generate proper models to interact with the digital information. In this approach a set of techniques covering both fields (computer vision and graphics) have been used to develop a complete process from the medical image to the surgery training.Item Visual Language Generalization for Procedural Modeling of Buildings(The Eurographics Association, 2012) Barroso, Santiago; Patow, Gustavo; Isabel Navazo and Gustavo PatowProcedural modeling has become the accepted standard for the creation of detailed large scenes, in particular urban landscapes. With the introduction of visual languages there has been a huge leap forward in terms of usability, but there is still need of more sophisticated tools to simplify the development process. In this paper we present extensions to the visual modeling of procedural buildings, which adapt concepts from general purpose programming languages, with the objective of providing higher descriptive power. In particular, we present the concepts of visual modules, parameter linking and the possibility to seamlessly add abstract parameter templates to the designer visual toolbox. We base our demonstrations on a new visual language created for volume-based models like historic architectonic structures (aqueducts, churches, cathedrals, etc.), which cannot be modeled as 2D facades because of the intrinsic volumetric structure of these construction (e.g. vaults or arches).Item Computing Curvature Information on 3D Meshes from Cultural Heritage Artifacts(The Eurographics Association, 2012) López, L.; Torres, J. C.; Soler, F.; Isabel Navazo and Gustavo PatowThe curvature provides essential information about the features of a object surface. This poster presents an operation that makes it possible to generate the curvature information in the CHiSEL system.Item Generating Coherent Ray Directions in Path Tracing(The Eurographics Association, 2012) Torres, Roberto; Martín, Pedro J.; Gavilanes, Antonio; Isabel Navazo and Gustavo PatowThe quality of the images produced by a global illumination rendering engine is highly connected to the number of paths that are randomly generated from the camera to the light sources. Graphics Processing Units (GPUs) have been used to implement renderers by typically binding each thread to a ray. Nevertheless, this purely random generation does not fit well on the architecture of current GPUs, due to their SIMD nature. We modify the way paths are extended in order to take the most of GPUs. The arrangement of rays is split into groups of contiguous rays. The hemisphere on each intersection point is divided into spherical patches, and the same patch is chosen for all the rays in the group. The next direction for each path will be randomly chosen on that patch. Thus, if the intersection points of a group are near, the new rays spawned will be similar. We have implemented different configurations of this idea on a path tracer in CUDA and they have been experimentally tested on usual scenes. In the same amount of time, most of our algorithms complete more paths and, therefore, they produce images of higher quality than those obtained by the purely random generation.Item Evaluating Three Versions of an Augmented Reality Mobile Game about Recycling(The Eurographics Association, 2012) Furió, D.; Juan, M.-Carmen; Alem, L.; Ashworth, P.; Isabel Navazo and Gustavo PatowWe present three versions of an Augmented Reality (AR) game (basic, collaborative and competitive) for changing people attitudes with regard to climate change. We present a study in which twenty-eight primary school students have participated. To explore the extent to which the three AR game versions affected different aspects, the children had to answer questionnaires. The results did not show significant differences between the three versions. However, having into account the means and children preference, the competitive version could have had more influence on the participants.Item Uncertainty Visualization of Brain Fibers(The Eurographics Association, 2012) Hermosilla, Pedro; Brecheisen, Ralph; Vázquez, Pere-Pau; Vilanova, Anna; Isabel Navazo and Gustavo PatowDiffuse Tensor Imaging (DTI) is an acquisition method based on Magnetic Resonance (MR) that provides information on the white matter fiber pathways in the living human brain. Such knowledge is crucial for understanding the way different parts of the brain work and how they interact with each other. The reconstruction of fiber tracts, however, depends on a number of parameters that introduce a degree of uncertainty in the data. Together with the parameter setting, other elements such as noise, motion, partial volume effects, or image artifacts increase the uncertainty. Therefore, fiber tracking algorithms may produce misleading results. Visualizing such uncertainty is important to avoid taking wrong decisions in medical environments. In this paper we present a set of techniques that provide a better understanding on the visualization of brain fibers by means of textures, silhouettes, ambient occlusion, and animation.Item Differential Ray Marching(The Eurographics Association, 2012) Muñoz, Adolfo; Isabel Navazo and Gustavo PatowSeveral participating media rendering algorithms are based on ray marching: they integrate the variations of radiance along the volume covered by the participating media by splitting the path of light into segments and sampling light contribution at each of those segments. This paper revisits the concept of ray marching not as an integration technique, but as the application of a numerical method to solve an initial value differential equation. We present how to apply different numerical methods as ray marching techniques, analyze a wide range of them and study their applicability under different scenarios. Furthermore, we show how each of them improves over traditional ray marching. Any participating media rendering algorithm that is based on ray marching will benefit from the application of our technique by reducing the number of needed samples (and therefore, rendering time) and/or increasing accuracy.Item Locating Companies in 3D Urban Environments on the Internet(The Eurographics Association, 2012) Estrella, Ana M. López; Ortega, M. Dolores Robles; Alvarado, Lidia Ortega; Higueruela, Francisco R. Feito; Isabel Navazo and Gustavo Patow3D visualization is being incorporated in a lot of fields, including Geographic Information Systems (GIS). In addition, the Internet is the most popular method to find information, due to its accessibility. For this reason, most companies and businesses are interested in showing their products on the Web to make them well-known to many people. Considering all these concepts, this paper explains the process of developing a web application prototype with some GIS features. The main goal is to obtain business information, the location and the 2.5D navigation in an urban environment. In this way, through a web browser, the user will be able to search for companies by category, get information and see the scene from different levels of detail.