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Displaying 1-50 out of 57 total
Connectivity Oblivious Merging of Triangulations
Found in: 2012 XXV SIBGRAPI - Conference on Graphics, Patterns and Images (SIBGRAPI)
By Luis F. Silva,Luiz F. Scheidegger,Tiago Etiene,Joao L. D. Comba,Luis G. Nonato,Claudio T. Silva
Issue Date:August 2012
pp. 118-125
Simplicial meshes are extremely useful as discrete approximations of continuous spaces in numerical simulations. In some applications, however, meshes need to be modified over time. Mesh update operations are often expensive and brittle, which tends to mak...
 
A Report From VisWeek 2010
Found in: Computing in Science and Engineering
By Carlos Scheidegger, Cláudio T. Silva, Daniel Weiskopf
Issue Date:March 2011
pp. 70-77
<p>VisWeek 2010 covered the latest visualization and data analysis research and offered an excellent forum for discussing new trends in these fields.</p>
 
Using Python for Signal Processing and Visualization
Found in: Computing in Science and Engineering
By Erik W. Anderson, Gilbert A. Preston, Claudio T. Silva
Issue Date:July 2010
pp. 90-95
<p>Applying Python to a neuroscience project let developers put complex data processing and advanced visualization techniques together in a coherent framework.</p>
 
Direct Volume Rendering: A 3D Plotting Technique for Scientific Data
Found in: Computing in Science and Engineering
By Steven P. Callahan, Jason H. Callahan, Carlos E. Scheidegger, Claudio T. Silva
Issue Date:January 2008
pp. 88-92
Direct volume rendering is an effective method for plotting 3D scientific data, but it’s not used as frequently as it could be. Here, the authors summarize direct volume rendering and discuss barriers to taking advantage of this powerful technique.
 
Streaming-Enabled Parallel Data Flow Framework in the Visualization ToolKit
Found in: Computing in Science and Engineering
By Huy T. Vo,João L.D. Comba,Berk Geveci,Cláudio T. Silva
Issue Date:September 2011
pp. 72-83
A parallel dataflow framework implemented into VTK addresses the need for the streaming parallel computation in visualization pipelines.
 
User-Centered Multidimensional Projection Techniques
Found in: Computing in Science & Engineering
By Fernando V. Paulovich,Claudio T. Silva,Luis Gustavo Nonato
Issue Date:July 2012
pp. 74-81
Interactive multidimensional projections can be quite effective as interactive visualization tools. It's also advantageous to use local projection techniques over global ones when facing fully interactive applications.
 
Visibility-Based Prefetching for Interactive Out-Of-Core Rendering
Found in: Parallel and Large-Data Visualization and Graphics, IEEE Symposium on
By Wagner T. Corrêa, James T. Klosowski, Cláudio T. Silva
Issue Date:October 2003
pp. 2
We present a new visibility-based prefetching algorithm for interactive out-of-core rendering of large models on an inexpensive PC. Using an approximate visibility technique, we can very accurately and efficiently determine which geometry will be visible i...
 
Towards Point-Based Acquisition and Rendering of Large Real-World Environments
Found in: Graphics, Patterns and Images, SIBGRAPI Conference on
By Wagner T. Corrêa, Shachar Fleishman, Cláudio T. Silva
Issue Date:October 2002
pp. 59
Abstract. This paper describes a pipeline for the acquisition and rendering of large real-world environments. In the acquisition phase, we use a laser rangefinder to capture the geometry of an environment, and a digital camera to capture its colors. In the...
 
Guest Editorial: Special Section on Visualization 2005
Found in: IEEE Transactions on Visualization and Computer Graphics
By Cláudio T. Silva, Eduard Gröller, Holly Rushmeier
Issue Date:July 2006
pp. 419-420
No summary available.
 
Hardware-Accelerated Simulated Radiography
Found in: Visualization Conference, IEEE
By Daniel Laney, Steven P. Callahan, Nelson Max, Claudio T. Silva, Steven Langer, Randall Frank
Issue Date:October 2005
pp. 44
We present the application of hardware accelerated volume rendering algorithms to the simulation of radiographs as an aid to scientists designing experiments, validating simulation codes, and understanding experimental data. The techniques presented take a...
 
Progressive Volume Rendering of Large Unstructured Grids
Found in: IEEE Transactions on Visualization and Computer Graphics
By Steven P. Callahan,Louis Bavoil,Valerio Pascucci,Claudio T. Silva
Issue Date:September 2006
pp. 1307-1314
We describe a new progressive technique that allows real-time rendering of extremely large tetrahedral meshes. Our approach uses a client-server architecture to incrementally stream portions of the mesh from a server to a client which refines the quality o...
 
Interactive Rendering of Large Unstructured Grids Using Dynamic Level-of-Detail
Found in: Visualization Conference, IEEE
By Steven P. Callahan, Joao L. D. Comba, Peter Shirley, Claudio T. Silva
Issue Date:October 2005
pp. 26
We describe a new dynamic level-of-detail (LOD) technique that allows real-time rendering of large tetrahedral meshes. Unlike approaches that require hierarchies of tetrahedra, our approach uses a subset of the faces that compose the mesh. No connectivity ...
 
Revisiting Histograms and Isosurface Statistics
Found in: IEEE Transactions on Visualization and Computer Graphics
By Carlos E. Scheidegger, John M. Schreiner, Brian Duffy, Hamish Carr, Cláudio T. Silva
Issue Date:November 2008
pp. 1659-1666
Recent results have shown a link between geometric properties of isosurfaces and statistical properties of the underlying sampled data. However, this has two defects: not all of the properties described converge to the same solution, and the statistics com...
 
Computational Provenance
Found in: Computing in Science and Engineering
By Cláudio T. Silva, Joel E. Tohline
Issue Date:May 2008
pp. 9-10
Systematic mechanisms for capturing and exploring lineage information of digital artifacts are at the heart of a new field of research called computational provenance. This special issue aims to raise awareness and contribute to a better understanding of t...
 
Edge Transformations for Improving Mesh Quality of Marching Cubes
Found in: IEEE Transactions on Visualization and Computer Graphics
By Carlos A. Dietrich, Carlos E. Scheidegger, John Schreiner, João L.D. Comba, Luciana P. Nedel, Cláudio T. Silva
Issue Date:January 2009
pp. 150-159
Marching Cubes is a popular choice for isosurface extraction from regular grids due to its simplicity, robustness, and efficiency. One of the key shortcomings of this approach is the quality of the resulting meshes, which tend to have many poorly shaped an...
 
Provenance for Visualizations: Reproducibility and Beyond
Found in: Computing in Science and Engineering
By Claudio T. Silva, Juliana Freire, Steven P. Callahan
Issue Date:September 2007
pp. 82-89
The demand for the construction of complex visualizations is growing in many disciplines of science, as users are faced with ever increasing volumes of data to analyze. The authors present VisTrails, an open source provenance-management system that provide...
 
A Unified Infrastructure for Parallel Out-of-Core Isosurface Extraction and Volume Rendering of Unstructured Grids
Found in: Parallel and Large-Data Visualization and Graphics, IEEE Symposium on
By Yi-Jen Chiang, Ricardo Farias, Cláudio T. Silva, Bin Wei
Issue Date:October 2001
pp. 59-66
<p>In this paper, we present a unified infrastructure for parallel out-of-core isosurface extraction and volume rendering of large unstructured grids on distributed-memory parallel machines. We parallelize the out-of-core isosurface extraction algori...
 
A Memory Insensitive Technique for Large Model Simplification
Found in: Visualization Conference, IEEE
By Peter Lindstrom, Cláudio T. Silva
Issue Date:October 2001
pp. N/A
In this paper we propose three simple, but significant improvements to the OoCS (Out-of-Core Simplification) algorithm of Lindstrom which increase the quality of approximations and extend the applicability of the algorithm to an even larger class of comput...
 
Scientific Exploration in the Era of Ocean Observatories
Found in: Computing in Science and Engineering
By António Baptista, Bill Howe, Juliana Freire, David Maier, Cláudio T. Silva
Issue Date:May 2008
pp. 53-58
The authors introduce an ocean observatory, offer a vision of observatory-enabled scientific exploration, and discuss the requirements and approaches for generating provenance-aware products in such environments.
 
Interactive Out-Of-Core Isosurface Extraction
Found in: Visualization Conference, IEEE
By Yi-Jen Chiang, Cláudio T. Silva, William J. Schroeder
Issue Date:October 1998
pp. 167
In this paper, we present a novel out-of-core technique for the interactive computation of isosurfaces from volume data. Our algorithm minimizes the main memory and disk space requirements on the visualization workstation, while speeding up isosurface extr...
 
Visual Exploration of Big Spatio-Temporal Urban Data: A Study of New York City Taxi Trips
Found in: IEEE Transactions on Visualization and Computer Graphics
By Nivan Ferreira,Jorge Poco,Huy T. Vo,Juliana Freire,Claudio T. Silva
Issue Date:December 2013
pp. 2149-2158
As increasing volumes of urban data are captured and become available, new opportunities arise for data-driven analysis that can lead to improvements in the lives of citizens through evidence-based decision making and policies. In this paper, we focus on a...
 
Bandwidth Selection and Reconstruction Quality in Point-Based Surfaces
Found in: IEEE Transactions on Visualization and Computer Graphics
By Hao Wang, Carlos E. Scheidegger, Cláudio T. Silva
Issue Date:July 2009
pp. 572-582
We investigate the influence of bandwidth selection in the reconstruction quality of point-based surfaces. While the problem has received relatively little attention in the literature, we show that appropriate selection plays a significant role in the qual...
 
Managing the Evolution of Dataflows with VisTrails
Found in: Data Engineering Workshops, 22nd International Conference on
By Steven P. Callahan, Juliana Freire, Juliana Freire, Emanuele Santos, Carlos E. Scheidegger, Claudio T. Silva, Huy T. Vo
Issue Date:April 2006
pp. 71
Scientists are now faced with an incredible volume of data to analyze. To successfully analyze and validate various hypotheses, it is necessary to pose several queries, correlate disparate data, and create insightful visualizations of both the simulated pr...
 
VisTrails: Enabling Interactive Multiple-View Visualizations
Found in: Visualization Conference, IEEE
By Louis Bavoil, Steven P. Callahan, Carlos E. Scheidegger, Huy T. Vo, Patricia J. Crossno, Claudio T. Silva, Juliana Freire
Issue Date:October 2005
pp. 18
VisTrails is a new system that enables interactive multiple-view visualizations by simplifying the creation and maintenance of visualization pipelines, and by optimizing their execution. It provides a general infrastructure that can be combined with existi...
 
A Survey of Visibility for Walkthrough Applications
Found in: IEEE Transactions on Visualization and Computer Graphics
By Daniel Cohen-Or, Yiorgos L. Chrysanthou, Cláudio T. Silva, Frédo Durand
Issue Date:July 2003
pp. 412-431
<p><b>Abstract</b>—Visibility algorithms for walkthrough and related applications have grown into a significant area, spurred by the growth in the complexity of models and the need for highly interactive ways of navigating them. In this s...
 
Integrating Occlusion Culling with View-Dependent Rendering
Found in: Visualization Conference, IEEE
By Jihad El-Sana, Neta Sokolovsky, Claudio T. Silva
Issue Date:October 2001
pp. N/A
We present a novel approach that integrates occlusion culling within the view-dependent rendering framework. View-dependent rendering provides the ability to change level of detail over the surface seamlessly and smoothly in real-time. The exclusive use of...
 
An Exact Interactive Time Visibility Ordering Algorithm for Polyhedral Cell Complexes
Found in: Volume Visualization and Graphics, IEEE Symposium on
By Joseph S. B. Mitchell, Peter L. Williams, Cláudio T. Silva
Issue Date:October 1998
pp. 87-94
A visibility ordering of a set of objects, from a given viewpoint, is a total order on the objects such that if object a obstructs object b, then b preceeds a in the ordering. Such orderings are extremely useful for rendering volumetric data. We present an...
 
Point Set Surfaces
Found in: Visualization Conference, IEEE
By Marc Alexa, Johannes Behr, Daniel Cohen-Or, Shachar Fleishman, David Levin, Claudio T. Silva
Issue Date:October 2001
pp. N/A
We advocate the use of point sets to represent shapes. We provide a definition of a smooth manifold surface from a set of points close to the original surface. The definition is based on local maps from differential geometry, which are approximated by the ...
 
Rendering on a Budget: A Framework for Time-Critical Rendering
Found in: Visualization Conference, IEEE
By James T. Klosowski, Cláudio T. Silva
Issue Date:October 1999
pp. 17
<div>We present a technique for optimizing the rendering of high-depth complexity scenes. Prioritized-Layered Projection (PLP) does this by rendering an estimation of the visible set for each frame. The novelty in our work lies in the fact that we do...
 
Computing and Rendering Point Set Surfaces
Found in: IEEE Transactions on Visualization and Computer Graphics
By Marc Alexa, Johannes Behr, Daniel Cohen-Or, Shachar Fleishman, David Levin, Claudio T. Silva
Issue Date:January 2003
pp. 3-15
<p><b>Abstract</b>—We advocate the use of point sets to represent shapes. We provide a definition of a smooth manifold surface from a set of points close to the original surface. The definition is based on local maps from differential geo...
 
Out-Of-Core Rendering of Large, Unstructured Grids
Found in: IEEE Computer Graphics and Applications
By Ricardo Farias, Cláudio T. Silva
Issue Date:July 2001
pp. 42-50
The authors address the problem of rendering large unstructured volumetric grids on machines with limited memory. They present a set of techniques that can be used to render arbitrarily large data sets on machines with very little memory. The authors prese...
 
Simple, Fast, and Robust Ray Casting of Irregular Grids
Found in: Scientific Visualization Conference
By Paul Bunyk, Arie Kaufman, Claudio T. Silva
Issue Date:June 1997
pp. 30
In this paper we describe a simple and efficient ray casting engine that is suitable for the rapid exploration of irregular grids composed of tetrahedra cells, or other cell complexes where cells have been broken up into faces. In our method, in a preproce...
 
Hardware-Assisted Point-Based Volume Rendering of Tetrahedral Meshes
Found in: Graphics, Patterns and Images, SIBGRAPI Conference on
By Erik W. Anderson, Steven P. Callahan, Carlos E. Scheidegger, John M. Schreiner, Claudio T. Silva
Issue Date:October 2007
pp. 163-172
Unstructured volume grids are ubiquitous in scientific computing, and have received substantial interest from the scientific visualization community. In this paper, we take a point-based approach to rendering unstructured grids. In particular, we present a...
 
Efficient Conservative Visibility Culling Using the Prioritized-Layered Projection Algorithm
Found in: IEEE Transactions on Visualization and Computer Graphics
By James T. Klosowski, Cláudio T. Silva
Issue Date:October 2001
pp. 365-379
<p><b>Abstract</b>—We propose a novel conservative visibility culling technique based on the Prioritized-Layered Projection (PLP) algorithm. PLP is a time-critical rendering technique that computes, for a given viewpoint, a partially corr...
 
Two-Phase Mapping for Projecting Massive Data Sets
Found in: IEEE Transactions on Visualization and Computer Graphics
By Fernando V. Paulovich, Claudio T. Silva, Luis G. Nonato
Issue Date:November 2010
pp. 1281-1290
Most multidimensional projection techniques rely on distance (dissimilarity) information between data instances to embed high-dimensional data into a visual space. When data are endowed with Cartesian coordinates, an extra computational effort is necessary...
 
Marching Cubes without Skinny Triangles
Found in: Computing in Science and Engineering
By Carlos A. Dietrich, Carlos E. Scheidegger, João L.D. Comba, Luciana P. Nedel, Cláudio T. Silva
Issue Date:March 2009
pp. 82-87
Most computational codes that use irregular grids depend on the single worst triangle's quality: skinny triangles can lead to bad performance and numerical instabilities. Marching cubes (MC) is the standard isosurface grid generation algorithm, and, wherea...
 
Provenance in Comparative Analysis: A Study in Cosmology
Found in: Computing in Science and Engineering
By Erik W. Anderson, James P. Ahrens, Katrin Heitmann, Salman Habib, Cláudio T. Silva
Issue Date:May 2008
pp. 30-37
Provenance—the logging of information about how data came into being and how it was processed—is an essential aspect of managing large-scale simulation and data-intensive projects. Using a cosmology code comparison project as an example, this article prese...
 
Provenance for Computational Tasks: A Survey
Found in: Computing in Science and Engineering
By Juliana Freire, David Koop, Emanuele Santos, Cláudio T. Silva
Issue Date:May 2008
pp. 11-21
The problem of systematically capturing and managing provenance for computational tasks has recently received significant attention because of its relevance to a wide range of domains and applications. The authors give an overview of important concepts rel...
 
PVR: High-Performance Volume Rendering
Found in: Computing in Science and Engineering
By Cláudio T. Silva, Arie E. Kaufman, Constantine Pavlakos
Issue Date:December 1996
pp. 18-28
<p>Traditional volume rendering methods are too slow to provide interactive visualization, especially for large 3D data sets. The PVR system implements parallel volume rendering techniques that speed up the visualization process. Moreover, it helps c...
 
Ultrascale Visualization of Climate Data
Found in: Computer
By Dean N. Williams,Timo Bremer,Charles Doutriaux,John Patchett,Sean Williams,Galen Shipman,Ross Miller,David R. Pugmire,Brian Smith,Chad Steed,E. Wes Bethel,Hank Childs,Harinarayan Krishnan,Prabhat Prabhat,Michael Wehner,Claudio T. Silva,Emanuele Santos,David Koop,Tommy Ellqvist,Jorge Poco,Berk Geveci,Aashish Chaudhary,Andy Bauer,Alexander Pletzer,Dave Kindig,Gerald L. Potter,Thomas P. Maxwell
Issue Date:September 2013
pp. 68-76
Collaboration across research, government, academic, and private sectors is integrating more than 70 scientific computing libraries and applications through a tailorable provenance framework, empowering scientists to exchange and examine data in novel ways...
 
Making Computations and Publications Reproducible with VisTrails
Found in: Computing in Science & Engineering
By Juliana Freire,Claudio T. Silva
Issue Date:July 2012
pp. 18-25
The VisTrails system supports the creation of reproducible experiments. VisTrails integrates data acquisition, derivation, analysis, and visualization as executable components throughout the scientific exploration process, and through systematic provenance...
 
Interactive Vector Field Feature Identification
Found in: IEEE Transactions on Visualization and Computer Graphics
By Joel Daniels II, Erik W. Anderson, Luis Gustavo Nonato, Cláudio T. Silva
Issue Date:November 2010
pp. 1560-1568
We introduce a flexible technique for interactive exploration of vector field data through classification derived from userspecified feature templates. Our method is founded on the observation that, while similar features within the vector field may bespat...
 
Template-Based Remeshing for Image Decomposition
Found in: Graphics, Patterns and Images, SIBGRAPI Conference on
By Mario A.S. Lizier, Marcelo F. Siqueira, Joel Daniels II, Claudio T. Silva, Luis G. Nonato
Issue Date:September 2010
pp. 95-102
This paper presents a novel quad-based remeshing scheme, which can be regarded as a replacement for the triangle-based improvement step of an existing image-based mesh generation technique called Imesh. This remeshing scheme makes it possible for the algor...
 
Robust Smooth Feature Extraction from Point Clouds
Found in: Shape Modeling and Applications, International Conference on
By Joel II Daniels, Linh K. Ha, Tilo Ochotta, Claudio T. Silva
Issue Date:June 2007
pp. 123-136
Defining sharp features in a given 3D model facilitates a better understanding of the surface and aids visualizations, reverse engineering, filtering, simplification, non-photo realism, reconstruction and other geometric processing applications. We present...
 
Hardware-Assisted Visibility Sorting for Unstructured Volume Rendering
Found in: IEEE Transactions on Visualization and Computer Graphics
By Steven P. Callahan, Milan Ikits, João L.D. Comba, Cláudio T. Silva
Issue Date:May 2005
pp. 285-295
Harvesting the power of modern graphics hardware to solve the complex problem of real-time rendering of large unstructured meshes is a major research goal in the volume visualization community. While, for regular grids, texture-based techniques are well-su...
 
Image-Space Visibility Ordering for Cell Projection Volume Rendering of Unstructured Data
Found in: IEEE Transactions on Visualization and Computer Graphics
By Richard Cook, Nelson Max, Cláudio T. Silva, Peter L. Williams
Issue Date:November 2004
pp. 695-707
Projection methods for volume rendering unstructured data work by projecting, in visibility order, the polyhedral cells of the mesh onto the image plane, and incrementally compositing each cell's color and opacity into the final image. Normally, such metho...
 
ZSWEEP: An Efficient and Exact Projection Algorithm for Unstructured Volume Rendering
Found in: Volume Visualization and Graphics, IEEE Symposium on
By Joseph S. B. Mitchell, Cláudio T. Silva, Ricardo Farias
Issue Date:October 2000
pp. 91-99
<p>We present a simple new algorithm that performs fast and memory-efficient cell projection for (exact) rendering of unstructured datasets. The main idea of the
 
The Lazy Sweep Ray Casting Algorithm for Rendering Irregular Grids
Found in: IEEE Transactions on Visualization and Computer Graphics
By Claudio T. Silva, Joseph S.B. Mitchell
Issue Date:April 1997
pp. 142-157
<p><b>Abstract</b>—<it>Lazy Sweep Ray Casting</it> is a fast algorithm for rendering general irregular grids. It is based on the sweep-plane paradigm, and it is able to accelerate ray casting for rendering irregular grids, inc...
 
Optimal bandwidth selection for MLS surfaces
Found in: Shape Modeling and Applications, International Conference on
By Hao Wang, Carlos E. Scheidegger, Claudio T. Silva
Issue Date:June 2008
pp. 111-120
We address the problem of bandwidth selection in MLS surfaces. While the problem has received relatively little attention in the literature, we show that appropriate selection plays a critical role in the quality of reconstructed surfaces. We formulate the...
 
The Prioritized-Layered Projection Algorithm for Visible Set Estimation
Found in: IEEE Transactions on Visualization and Computer Graphics
By James T. Klosowski, Cláudio T. Silva
Issue Date:April 2000
pp. 108-123
<p><b>Abstract</b>—<it>Prioritized-Layered Projection</it> (PLP) is a technique for fast rendering of high depth complexity scenes. It works by <it>estimating</it> the visible polygons of a scene from a given viewp...
 
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