CEIG12
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Item A Survey on Development Tools for Mobile Augmented Reality(The Eurographics Association, 2012) Rovelo, Gustavo; Abad, Francisco; Camahort, Emilio; Isabel Navazo and Gustavo PatowAugmented Reality (AR) applications have become more popular beyond the research laboratory due to recent technological breakthroughs in computer hardware and mobile devices. Users are starting to interact with virtual content mixed with real environments at their offices, homes, and schools using their mobile phones. For this growing market, developers have first to decide the platform in which they will develop the application (e.g. Apple iOS or Android). Then they must decide whether start writing the application from scratch using only platform native tools, or using one of the available Software Development Kits (SDKs), or using high-level authoring tools for the chosen platform. Besides, developers have to face different AR related issues according to the application's requirements: markers, barcodes or general image tracking, geolocation, efficient rendering of 3D objects, and designing a robust GUI for the target devices. To help developers and researchers to start writing mobile AR applications, this survey identifies the main features of several freeware and commercial SDKs and authoring tools.Item Design of an Information System for Cultural Heritage(The Eurographics Association, 2012) Soler, Francisco; Torres, Juan Carlos; León, Alejandro J.; Luzon, M. Victoria; Isabel Navazo and Gustavo PatowUsually the information that must be managed by archaeologist for any cultural heritage artefact is very heterogeneous. Due to its spatial nature this information cannot be easily represented with conventional data management frameworks. The strong spatial dependence of data concerning the object of study makes it interesting to have a three-dimensional model of the artefact to associate the large amount of information available. This paper presents a 3D information system that has been designed to manage cultural heritage information. The system allows to associate information layer to the artefact surface, following a GIS like approach. The association of information to the surface of the object allows to find out spatial relationships between different elements, making it easier to understand this information to both specialists and general public. The paper describes the system structure and functionality.Item Analysis of Coded Apertures for Defocus Deblurring of HDR Images(The Eurographics Association, 2012) Garcia, Luis; Presa, Lara; Gutierrez, Diego; Masia, Belen; Isabel Navazo and Gustavo PatowIn recent years, research on computational photography has reached important advances in the field of coded apertures for defocus deblurring. These advances are known to perform well for low dynamic range images (LDR), but nothing is written about the extension of these techniques to high dynamic range imaging (HDR). In this paper, we focus on the analysis of how existing coded apertures techniques perform in defocus deblurring of HDR images. We present and analyse three different methods for recovering focused HDR radiances from an input of blurred LDR exposures and from a single blurred HDR radiance, and compare them in terms of the quality of their results, given by the perceptual metric HDR-VDP2. Our research includes the analysis of the employment of different statistical deconvolution priors, made both from HDR and LDR images, performing synthetic experiments as well as real ones.Item Ventricular Puncture Trainer(The Eurographics Association, 2012) Pandiella, Imanol Muñoz; Monclús, Eva; Brunet, Pere; Conesa, Gerard; Isabel Navazo and Gustavo PatowThe learning process in neurosurgery is a large and difficult task based on experimentation, being ventriculostomy not an exception. We have developed a virtual reality system to help training novel surgeons on this kind of operation. The system consists of the simulation of the surgery using a haptic device and a subsequent 3D visual inspection of the surgical trajectory. Our main objective was to proof that the tactile sensation produced by our system was enough realistic for the surgeons. We carried out a demonstration session in a medical workshop where all surgeons attending the workshop used the system with a very enthusiastic response about the perception experimented through the system.Item Tracking for Virtual Environment using Kinect(The Eurographics Association, 2012) Sánchez, M. García; Salas, A. León; Cantero, J. C. Torres; Isabel Navazo and Gustavo PatowLos sistemas de tracking magnético suelen tener alcance limitado y presenta problemas de interferencias. En este trabajo proponemos utilizar los sensores de kinect para realizar el tracking en sistemas HMD.Item Design of a Scalable System for the Sensorization of Virtual TV Sets with Live Broadcast(The Eurographics Association, 2012) Méndez, Roi; Sanmartín, Gabriel; Mera, David; Flores, Julián; Castelló, Enrique; Isabel Navazo and Gustavo PatowThe sensorization of virtual tv sets using motion capture systems allows the automation of many of the processes implied in the live broadcast of a tv show. It facilitates the tasks of both the actor (allowing him to interact with the environment) and the technicians (camera position and orientation, real objects position, etc.). Adding new sensors usually derives in an increase of the load of the render computer and therefore a decrease in the frame rate. This increase in the load is due to the captured data processing and its application to the scene, that must be computed in parallel to the render by the same computer. This article presents a centralized hardware and software architecture that allows the addition of an unlimited number of sensors without directly affecting the frame rate of the render. The system centralizes in a single PC all the data captured by the different sensors, giving a suitable format to this data and updating the appropriate variables across the network transparently to the rendering program, keeping a stable and unaffected render time.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 3D Interaction with Smartphone-like Devices(The Eurographics Association, 2012) Rodríguez, A.; León, A.; Torres, J. C.; Isabel Navazo and Gustavo Patow3D applications require a series of 3D operations that are difficult to perform with the traditional interaction devices such as mouse and keyboard. In this paper we present a new 3D interaction system using smartphone-like devicesItem Interactive Virtual Tours with Panoramic Video(The Eurographics Association, 2012) Pérez, J.; Tamayo, I.; Garcia, J.; Isabel Navazo and Gustavo PatowThis paper presents the work being carried out in the context of 360IN project for the development of an interactive platform for panoramic video on the web. The purpose of this platform is to have an application where the user can perform interactive virtual tours and get extra information concerning points of interest that are in the course.Item More Stable SPH-based Fluid Simulation(The Eurographics Association, 2012) Perea, Juan J.; Cordero, Juan M.; Isabel Navazo and Gustavo PatowThe simulation of fluid is a field largely discussed, from the viewpoint of engineering, in the so-called computational fluid dynamics (CFD). A problem that occurs repeatedly in the literature of CFD is the stability of the simulation. One of the elements that introduce instability in any CFD model is the temporal integration method. Among the most commonly used CFD techniques, both in the field of engineering and in the computer graphics, is SPH, which is particularly relevant to its computational simplicity. However, this technique adds stability problems due to the treatment of viscous and pressure terms arising from the formulation of Navier'Stokes. SPH also introduces greater instability by the need to use interpolation functions appropriate to the phenomena that occur in fluid dynamics. We present solutions to these four problems of inestability mentioned: treatment of the terms of pressure and viscosity that appear in the Navier'Stokes, the formulation of the characteristic interpolation function of SPH and treatment of temporal integration.Item Kinamo: Gait Analysis System(The Eurographics Association, 2012) Martínez, H.; Gil-Gómez, J. A.; Martínez-Gramage, J.; Juan, M. C.; Isabel Navazo and Gustavo PatowThe gait analysis is a fundamental technique for functional assessment of patients with gait problems. This analysis is generally available to few patients because the systems needed to carry it out have a high cost. In this paper, we present a novel system, Kinamo, which allows to decrease drastically the cost when performing the gait analysis using Kinect cameras, which not only allows the reduction of cost, but also facilitates the acquisition conditions.Item Teaching Tool for Self-learning and Self-evaluation of Human Anatomy Using 3D Models of Human Bones(The Eurographics Association, 2012) Pamos, Miguel Á.; Segura, Rafael; Isabel Navazo and Gustavo PatowIn this research, it's going to introduce the process we have applied by development an application intended to students of Physioteraphy Studies, The proccess is divided by three sub-process: scanning bones, processing models and developing the software application. As a result, we have found a useful and user friendly desktop application which increases the knowledge of the students about the course of General Anatomy of the University of Jaén.Item A GPU Based Method for the Automatic Generation of Near-Optimal Navigation Meshes(The Eurographics Association, 2012) Oliva, Ramon; Pelechano, Nuria; Isabel Navazo and Gustavo PatowIn this paper we present a novel, robust and efficient GPU based technique to automatically generate a Navigation Mesh for complex 3D scenes. Our method consists of two steps: firstly, starting with a 3D scene representing a complex environment of one floor with slopes, steps, and other obstacles, it automatically generates a 2D representation based on a single polygon (floor) with holes (obstacles).This step can handle degeneracies of the starting 3D scene model, such as interpenetrating geometry. Secondly, a novel method that exploits the GPU efficiency is used to automatically generate a near-optimal convex decomposition which will represent the cell and portal graph of the environment. Such convex decomposition is a 2D representation of the walkable areas of the environment with portals indicating the crossing borders. The results show that the presented technique not only is more robust than previous CPU methods, but also for the tested environments with up to 1000 vertices, it performs five times faster.Item Multi-resolution Myocardial Architecture Study(The Eurographics Association, 2012) Poveda, F.; Gil, D.; Gurgui, T.; Marti, E.; Isabel Navazo and Gustavo PatowMyocardial complexity has lead to vivid controversy in the interpretation of the cardiac form and function over the years. This complexity has not been clarified yet even with the most recent computational reconstructions of low level MRI data.We propose a data-based multi-resolution methodology and validation to tackle this problem.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 PrimeSense Sensors as a Low-cost Method for Motion Capture on Clinical Tests(The Eurographics Association, 2012) Sanmartín, G.; Flores, J.; Arias, P.; Cudeiro, J.; Méndez, R.; Isabel Navazo and Gustavo PatowVirtual Reality (VR) is the computer recreation of simulated environments that create on the user a sense of physical presence. VR provides the advantages of being highly flexible and controllable, allowing experts to generate the optimal conditions for any given test and isolating any desired variables in the course of an experiment. An important feature of VR is that it allows interaction within the virtual world. Motion capture is one of the most popular technologies, because it contributes to creating in the subject the sense of presence. There are several methods to incorporate these techniques into an VR system, with the challenge of them not being too invasive. We propose a method using PrimeSense sensors and several computer vision techniques to build a low-cost system that has proven to be valid in its application as a support therapy for Parkinson's disease (PD) patients.Item Lineal Hull: Two Algorithms for Convex Hull(The Eurographics Association, 2012) Sánchez, M. García; Salas, A. León; Cantero, J. C. Torres; Isabel Navazo and Gustavo PatowThis poster proposes a concept that improves the existing algorithms for convex hull. This concept can be applied whether the initial points are sorted or not. The results show a comparation with Quick-Hull (QH) [BDH96]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 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.