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Now showing 1 - 6 of 6
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    Extending Industrial Digital Twins with Optical Object Tracking
    (The Eurographics Association, 2017) Tammaro, Antonio; Segura, Álvaro; Moreno, Aitor; Sánchez, Jairo R.; Fco. Javier Melero and Nuria Pelechano
    In the last year, the concept of Industry 4.0 and smart factories has increasingly gained more importance. One of the central aspects of this innovation is the coupling of physical systems with a corresponding virtual representation, known as the Digital Twin. This technology enables new powerful applications, such as real-time production optimization or advanced cloud services. To ensure the real-virtual equivalence it is necessary to implement multimodal data acquisition frameworks for each production system using their sensing capabilities, as well as appropriate communication and control architectures. In this paper we extend the concept of the digital twin of a production system adding a virtual representation of its operational environment. In this way the paper describes a proof of concept using an industrial robot, where the objects inside its working volume are captured by an optical tracking system. Detected objects are added to the digital twin model of the cell along with the robot, having in this way a synchronized virtual representation of the complete system that is updated in real time. The paper describes this tracking system as well as the integration of the digital twin in a Web3D based virtual environment that can be accessed from any compatible devices such as PCs, tablets and smartphones.
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    Dissipation Potentials for Yarn-Level Cloth
    (The Eurographics Association, 2017) Sánchez-Banderas, Rosa M.; Otaduy, Miguel A.; Fco. Javier Melero and Nuria Pelechano
    Damping is a critical phenomenon in determining the dynamic behavior of animated objects. For yarn-level cloth models, setting the correct damping behavior is particularly complicated, because common damping models in computer graphics do not account for the mixed Eulerian-Lagrangian discretization of efficient yarn-level models. In this paper, we show how to derive a damping model for yarn-level cloth from dissipation potentials. We develop specific formulations for the deformation modes present in yarn-level cloth, circumventing various numerical difficulties. We show that the proposed model enables independent control of the damping behavior of each deformation mode, unlike other previous models.
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    Direct Volume Rendering of Stack-Based Terrains
    (The Eurographics Association, 2017) Graciano, Alejandro; Rueda, Antonio J.; Feito, Francisco R.; Fco. Javier Melero and Nuria Pelechano
    Traditionally, the rendering of volumetric terrain data, as many other scientific 3D data, has been carried out performing direct volume rendering techniques on voxel-based representations. A main problem with this kind of representation is its large memory footprint. Several solutions have emerged in order to reduce the memory consumption and improve the rendering performance. An example of this is the hierarchical data structures for space division based on octrees. Although these representations have produced excellent outcomes, especially for binary datasets, their use in data containing internal structures and organized in a layered style, as in the case of surface-subsurface terrain, still leads to a high memory usage. In this paper, we propose the use of a compact stack-based representation for 3D terrain data, allowing a real-time rendering using classic volume rendering procedures. In contrast with previous work that used this representation as an assistant for rendering purposes, we suggest its use as main data structure maintaining the whole dataset in the GPU in a compact way. Furthermore, the implementation of some visual operations included in geoscientific applications such as borehole visualization, attenuation of material layers or cross sections has been carried out.
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    A Curvature-based Method for Identifying the Contact Zone Between Bone Fragments: First Steps
    (The Eurographics Association, 2017) Jiménez-Pérez, J. Roberto; Paulano-Godino, Félix; Jiménez-Delgado, Juan J.; Fco. Javier Melero and Nuria Pelechano
    The use of computer-assisted procedures before or during surgery provides orthopaedic specialists additional information that help them to reduce surgery time and to improve the understanding of the fracture peculiarities. In this context, the calculation of the fracture area is one of the main tasks in order to better comprehend the fracture. This paper presents the initial results of a method for the calculation of the contact zone between bone fragments by using a curvature-based approach. The method only considers cortical tissue, thus it is robust again the deformation or lack of trabecular tissue because of the fracture. In the case of simple fractures, the contact zone coincides with the entire fracture area. However, the calculation of the contact zone in complex fractures avoids calculating correspondences between fragments; hence the proposed method favours the use of puzzle solving methods in order to address the fracture reduction computation. Our proposal is able to overcome the initial limitations of curvature-based methods such as noise sensitivity, and shows a robust behaviour under circumstances of inexact segmentation or low precision.
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    An Improved Parallel Technique for Neighbour Search on CUDA
    (The Eurographics Association, 2017) Perea, Juan J.; Cordero, Juan M.; Fco. Javier Melero and Nuria Pelechano
    In Computer Graphics is usual the modelling of dynamic systems through particles. The simulation of liquids, cloths, gas, smoke... are highlighted examples of that modelling. In this scope, is particularly relevant the procedure of neighbour particles searching, which represents a bottleneck in terms of computational cost. One of the most used searching techniques is the cell- based spatial division by cubes, where each cell is tagged by a hash value. Thus, all particles located into each cell have the same tag and are the candidate to be neighbours. The most useful feature of this technique is that it can be easily parallelized, what reduces the computational costs. Nevertheless, the parallelizing process has some drawbacks associated with data memory management. Also, during the process of neighbour search, it is necessary to trace into the adjacent cells to find neighbour particles, as a consequence, the computational cost is increased. To solve these shortcomings, we have developed a method that reduces the search space by considering the relative position of each particle in its own cell. This method, parallelized using CUDA, shows improvements in processing time and memory management over other ''standard'' spatial division techniques.
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    Physically Based Skeleton Tracking
    (The Eurographics Association, 2017) López-Gandía, Axel; Susín, Antonio; Fco. Javier Melero and Nuria Pelechano
    Skeleton tracking has multiple applications such as games, virtual reality, motion capture and more. One of the main challenges of pose detection is to be able to obtain the best possible quality with a cheap and easy-to-use device. In this work we propose a physically based method to detect errors and tracking issues which appear when we use low cost tracking devices such as Kinect. Therefore, we can correct the animation in order to obtain a smoother movement. We have implemented the Newton- Euler Algorithm, which allow us to compute the internal forces involved in a skeleton. In a common movement, forces are usually smooth without sudden variations. When the tracking yields poor results or invalid poses the internal forces become very large with a lot of variation. This allow us to detect when the tracking system fails and the animation needs to be inferred through different methods.