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Ítem Computational Geometry in the Preprocessing of Point Clouds for Surface Modeling(1999-12-01) RUIZ, OSCAR EDUARDO; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Gabriel-constrained Parametric Surface Triangulation(InTech, 2009-11-01) Ruiz OE; Externo Otras Dependencias; Cadavid, C.; Lalinde Pulido, J.G.; Externo Otras Dependencias; Beatriz Defez-Garcia; Ricardo Serrano; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThe Boundary Representation of a 3D manifold contains FACES (connected subsets of a parametric surface S( ): R2 -> R3). In many science and engineering applications it is cumbersome and algebraically difficult to deal with the polynomialÍtem Extending Marching Cubes with Adaptative Methods to obtain more accurate iso-surfaces(Springer Berlin Heidelberg, 2010) Congote, John; Moreno, Aitor; Barandiaran, Iñigo; Barandiaran, Javier; Ruíz, Oscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis work proposes an extension of the Marching Cubes algorithm, where the goal is to represent implicit functions with higher accuracy using the same grid size -- The proposed algorithm displaces the vertices of the cubes iteratively until the stop condition is achieved -- After each iteration, the difference between the implicit and the explicit representations is reduced, and when the algorithm finishes, the implicit surface representation using the modified cubical grid is more accurate, as the results shall confirm -- The proposed algorithm corrects some topological problems that may appear in the discretization process using the original gridÍtem Extending marching cubes with adaptative methods to obtain more accurate iso-surfaces(2010-01-01) Congote, John; Moreno, Aitor; Barandiaran, Inigo; Barandiaran, Javier; Ruiz OE; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem ERR - Extending Marching Cubes with Adaptative Methods to Obtain More Accurate Iso-surfaces(2010-08-01) RUIZ, OSCAR EDUARDO; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Extending Marching Cubes with Adaptative Methods to Obtain More Accurate Iso-surfaces.(2010-08-01) RUIZ, OSCAR EDUARDO; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Statistical tuning of Adaptive-Weight Depth Map Algorithm(Springer Berlin Heidelberg, 2011) Hoyos, Alejandro; Congote, John; Barandiaran, Iñigo; Acosta, Diego; Ruíz, Óscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEIn depth map generation, the settings of the algorithm parameters to yield an accurate disparity estimation are usually chosen empirically or based on unplanned experiments -- A systematic statistical approach including classical and exploratory data analyses on over 14000 images to measure the relative influence of the parameters allows their tuning based on the number of bad pixels -- Our approach is systematic in the sense that the heuristics used for parameter tuning are supported by formal statistical methods -- The implemented methodology improves the performance of dense depth map algorithms -- As a result of the statistical based tuning, the algorithm improves from 16.78% to 14.48% bad pixels rising 7 spots as per the Middlebury Stereo Evaluation Ranking Table -- The performance is measured based on the distance of the algorithm results vs. the Ground Truth by Middlebury -- Future work aims to achieve the tuning by using signicantly smaller data sets on fractional factorial and surface-response designs of experimentsÍtem Force-Displacement Model of Compliant Mechanisms using Assur Sub-Chains(Member Organization Mexico of IFToMM, 2011-11-01) Durango, Sebastian; Correa, Jorge; Ruiz OE; Restrepo, J.; Achiche, Sofiane; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis article develops a modular procedureto perform force-displacement modeling of planar ?exure-based compliant mechanisms (CMs). The procedure ismostly suitable for planar lumped CMs.Ítem Volume Visual Attention Maps (VVAM) in Ray-Casting Rendering(IOS Press, 2012) Beristain, Andoni; Congote, John; Ruíz, Óscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis paper presents an extension visual attention maps for volume data visualization, where eye fixation points become rays in the 3D space, and the visual attention map becomes a volume -- This Volume Visual Attention Map (VVAM) is used to interactively enhance a ray-casting based direct volume rendering DVR visualization -- The practical application of this idea into the biomedical image visualization field is explored for interactive visualizationÍtem Volume Ray Casting in WebGL(Intech Open, 2012) Congote, John; Kabongo, Luis; Moreno, Aitor; Segura, Alvaro; Beristain, Andoni; Posada, Jorge; Ruíz, Oscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Evaluation of interest point detectors for image information extraction(2012) Barandiaran, Iñigo; Goenetxea, Jon; Congote, John; Graña, Manuel; Ruíz, Oscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEInterest points extraction and matching is a common task in many computer vision based application, which are used in different domains, such as 3D reconstruction, object recognition, or tracking -- We present an evaluation of current state of the art about interest point extraction algorithms to measure several parameters, such as detection quality, invariance to rotation and scale transformation, and computational efficiencyÍtem Evaulation of interest point detectors for image information extraction(2012-01-01) Barandiarian, Inigo; Goenetxea, Jon; Congote, John; Ruiz OE; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEInterest points extraction and matching is a common task in many computer vision based application, which are used in different domains, such as 3D reconstruction, object recognition, or tracking. We present an evaluation of current state of the art aboutÍtem Volume Visual Attention Maps (VVAM) in Ray-Casting Rendering(Publisher IOS Press Lansdale, 2012-02-01) RUIZ, OSCAR EDUARDO; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Volume Ray Casting in WebGL(InTech, 2012-03-01) Congote, John; Kabongo, Luis; Moreno, Aitor; Segura, Alvaro; Ruiz OE; Posada, Jorge; Beristain, Andoni; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEReal-time 3D computer graphics systems usually handle surface description models (i.e. BRep representations) and use surface rendering techniques for visualization. Common 3D model formats such as VRML, X3D, COLLADA, U3D (some intended for the Web)Ítem Symetrical Observability of Kinematic Parameters in Symmetrical Parallel Mechanisms(2012-07-13) Durango, Sebastián; Restrepo, David; Ruiz OE; Restrepo, John; Achiche, Sofiane; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis article presents an application of symmetry group theory in kinematic identification of parallel mechanisms of nlegs legs.Ítem Introduction to low-cost motion-tracking for virtual rehabilitation(Springer International Publishing AG, 2014-01-01) Koenig S.; Ardanza A.; Cortes C.; De Mauro A.; Lange B.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAELow-cost motion sensors have seen tremendous increase in popularity in the past few years. Accelerometers, gyroscopes or cameras can be found in most available smart phones and gaming controllers. The Apple® iPhone, Nintendo® Wii™ and the PlayStatio® EyeToy™ are just a few examples where such technology is used to provide a more natural interaction for the user. Depth-sensing cameras by companies such as Microsoft, PrimeSense and Asus can enhance the user experience even further by enabling full-body interaction. This chapter will specifically discuss the use of the Microsoft® Kinect™ depth-sensing camera (Kinect) for rehabilitation of patients with motor disabilities. In addition, examples will be provided of how the Kinect can be used with off-the-shelf computer games or utilized in conjunction with modern game development tools such as the game engine Unity. The examples will outline concepts and required resources in order to enable the reader to use low-cost depth-sensing cameras for rehabilitation. © Springer-Verlag Berlin Heidelberg 2014.Ítem Robust CT to US 3D-3D Registration by using Principal Component Analysis and Kalman Filtering(2015-01-01) Echeverría, Rebeca; Cortes, Camilo; Bertelnsen, Alvaro; Ruiz OE; Macia, Ivan; Florez, Julian; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Ultrasound Image Dataset for Image Analysis Algorithms Evaluation(Springer International Publishing, 2015-08-12) Cortés, C.; Kabongo, Luis; Macia, Ivan; Florez, Julian; Ruiz, Oscar Eduardo; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThe use of ultrasound (US) imaging as an alternative for real-time computer assisted interventions is increasing. Growing usage of US occurs despite of US lower imaging quality compared to other techniques and its difficulty...Ítem Ultrasound Image Dataset for Image Analysis Algorithms Evaluation(Springer Verlag, 2016) Cortes, Camilo; Kabongo, Luis; Macia, Ivan; Ruíz, Óscar E.; Florez, Julian; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThe use of ultrasound (US) imaging as an alternative for real-time computer assisted interventions is increasing -- Growing usage of US occurs despite of US lower imaging quality compared to other techniques and its difficulty to be used with image analysis algorithms -- On the other hand, it is still difficult to find sufficient data to develop and assess solutions for navigation, registration and reconstruction at medical research level -- At present, manually acquired available datasets present significant usability obstacles due to their lack of control of acquisition conditions, which hinders the study and correction of algorithm design parameters -- To address these limitations, we present a database of robotically acquired sequences of US images from medical phantoms, ensuring the trajectory, pose and force control of the probe -- The acquired dataset is publicly available, and it is specially useful for designing and testing registration and volume reconstruction algorithmsÍtem Robust CT to US 3D-3D Registration by Using Principal Component Analysis and Kalman Filtering(2016-07) Echeverría, Rebeca; Cortes, Camilo; Bertelsen, Alvaro; Macia, Ivan; Ruíz, Óscar E.; Flórez, Julián; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEAlgorithms based on the unscented Kalman filter (UKF) have been proposed as an alternative for registration of point clouds obtained from vertebral ultrasound (US) and computerised tomography (CT) scans, effectively handling the US limited depth and low signaltonoise ratio -- Previously proposed methods are accurate, but their convergence rate is considerably reduced with initial misalignments of the datasets greater than or 30 mm -- We propose a novel method which increases robustness by adding a coarse alignment of the datasets’ principal components and batchbased point inclusions for the UKF -- Experiments with simulated scans with full coverage of a single vertebra show the method’s capability and accuracy to correct misalignments as large as and 90 mm -- Furthermore, the method registers datasets with varying degrees of missing data and datasets with outlier points coming from adjacent vertebrae