IEEE VIS Publication Dataset

Computer graphics has be successfully applied to architecture design. There is more demand to new applications. One of them, to be addressed in this work, is the code checking and visualization of the checking results.

We describe a general algorithm to produce compatible 3D triangulations from spatial decompositions. Such triangulations match edges and faces across spatial cell boundaries, solving several problems in graphics and visualization including the crack problem found in adaptive isosurface generation, triangulation of arbitrary grids (including unstructured grids), clipping, and the interval tetrahedrization problem. The algorithm produces compatible triangulations on a cell-by-cell basis, using a modified Delaunay triangulation with a simple point ordering rule to resolve degenerate cases and produce unique triangulations across cell boundaries. The algorithm is naturally parallel since it requires no neighborhood cell information, only a unique, global point numbering. We show application of this algorithm to adaptive contour generation; tetrahedrization of unstructured meshes; clipping and interval volume mesh generation.

We describe a method for processing large amounts of volumetric data collected from a Knife Edge Scanning Microscope (KESM). The neuronal data that we acquire consists of thin, branching structures extending over very large regions that prior volumetric representations have difficulty dealing with efficiently. Since the full volume data set can be extremely large, on-the-fly processing of the data is necessary.

Determining the three-dimensional structure of distant astronomical objects is a challenging task, given that terrestrial observations provide only one viewpoint. For this task, bipolar planetary nebulae are interesting objects of study because of their pronounced axial symmetry due to fundamental physical processes. Making use of this symmetry constraint, we present a technique to automatically recover the axisymmetric structure of bipolar planetary nebulae from two-dimensional images. With GPU-based volume rendering driving a nonlinear optimization, we estimate the nebula's local emission density as a function of its radial and axial coordinates, and we recover the orientation of the nebula relative to Earth. The optimization refines the nebula model and its orientation by minimizing the differences between the rendered image and the original astronomical image. The resulting model enables realistic 3D visualizations of planetary nebulae, e.g. for educational purposes in planetarium shows. In addition, the recovered spatial distribution of the emissive gas allows validating computer simulation results of the astrophysical formation processes of planetary nebulae.

This poster abstract presents a scalable information visualization system for mobile devices and desktop systems. It is designed to support the operation and the workflow of wastewater systems. The regarded information data includes general information about buildings and units, process data, occupational safety regulations, work directions and first aid instructions in case of an accident. Technically, the presented framework combines visualization with agent technology in order to automatically scale various visualization types to fit on different platforms like PDAs (Personal Digital Assistants) or Tablet PCs. The implementation is based on but not limited to SQL, JSP, HTML and VRML.

This paper describes a Data Management System for Multimedial Information Visualization called DaMI. It is possible to create 2D or 3D model based on data out of standard databases and additional metainformation. DaMI is a generic system guaranteeing an optimal reusability and compatibility.

We explore techniques to detect and visualize features in data from molecular dynamics (MD) simulations. Although the techniques proposed are general, we focus on silicon (Si) atomic systems. The first set of methods use 3D location of atoms. Defects are detected and categorized using local operators and statistical modeling. Our second set of exploratory techniques employ electron density data. This data is visualized to glean the defects. We describe techniques to automatically detect the salient isovalues for isosurface extraction and designing transfer functions. We compare and contrast the results obtained from both sources of data. Essentially, we find that the methods of defect (feature) detection are at least as robust as those based on the exploration of electron density for Si systems.

We present a system for simulating and visualizing the propagation of dispersive contaminants with an application to urban security. In particular, we simulate airborne contaminant propagation in open environments characterised by sky-scrapers and deep urban canyons. Our approach is based on the multiple relaxation time lattice Boltzmann model (MRTLBM), which can efficiently handle complex boundary conditions such as buildings. In addition, we model thermal effects on the flow field using the hybrid thermal MRTLBM. Our approach can also accommodate readings from various sensors distributed in the environment and adapt the simulation accordingly. We accelerate the computation and efficiently render many buildings with small textures on the GPU. We render streamlines and the contaminant smoke with self-shadowing composited with the textured buildings.

Effective visualization of vector fields relies on the ability to control the size and density of the underlying mapping to visual cues used to represent the field. In this paper we introduce the use of a reaction-diffusion model, already well known for its ability to form irregular spatio-temporal patters, to control the size, density, and placement of the vector field representation. We demonstrate that it is possible to encode vector field information (orientation and magnitude) into the parameters governing a reaction-diffusion model to form a spot pattern with the correct orientation, size, and density, creating an effective visualization. To encode direction we texture the spots using a light to dark fading texture. We also show that it is possible to use the reaction-diffusion model to visualize an additional scalar value, such as the uncertainty in the orientation of the vector field. An additional benefit of the reaction-diffusion visualization technique arises from its automatic density distribution. This benefit suggests using the technique to augment other vector visualization techniques. We demonstrate this utility by augmenting a LIC visualization with a reaction-diffusion visualization. Finally, the reaction-diffusion visualization method provides a technique that can be used for streamline and glyph placement.

We present a fast, topology-preserving approach for isosurface simplification. The underlying concept behind our approach is to preserve the disconnected surface components in cells during isosurface simplification. We represent isosurface components in a novel representation, called enhanced cell, where each surface component in a cell is represented by a vertex and its connectivity information. A topology-preserving vertex clustering algorithm is applied to build a vertex octree. An enhanced dual contouring algorithm is applied to extract error-bounded multiresolution isosurfaces from the vertex octree while preserving the finest resolution isosurface topology. Cells containing multiple vertices are properly handled during contouring. Our approach demonstrates better results than existing octree-based simplification techniques.

We present the definition and computational algorithms for a new class of surfaces which are dual to the isosurface produced by the widely used marching cubes (MC) algorithm. These new isosurfaces have the same separating properties as the MC surfaces but they are comprised of quad patches that tend to eliminate the common negative aspect of poorly shaped triangles of the MC isosurfaces. Based upon the concept of this new dual operator, we describe a simple, but rather effective iterative scheme for producing smooth separating surfaces for binary, enumerated volumes which are often produced by segmentation algorithms. Both the dual surface algorithm and the iterative smoothing scheme are easily implemented.

We introduce a novel span-triangle data structure, based on the span-space representation for isosurfaces. It stores all necessary cell information for dynamic manipulation of the isovalue in an efficient way. We have found that using our data structure in combination with point-based techniques, implemented on graphics hardware, effects in real-time rendering and exploration. Our extraction algorithm utilizes an incremental and progressive update scheme, enabling smooth interaction without significant latency. Moreover, the corresponding visualization pipeline is capable of processing large data sets by utilizing all three levels of memory: disk, system and graphics. We address practical usability in actual medical applications, achieving a new level of interactivity.

Diffusion tensor imaging (DTI) is a magnetic resonance imaging method that can be used to measure local information about the structure of white matter within the human brain. Combining DTI data with the computational methods of MR tractography, neuroscientists can estimate the locations and sizes of nerve bundles (white matter pathways) that course through the human brain. Neuroscientists have used visualization techniques to better understand tractography data, but they often struggle with the abundance and complexity of the pathways. We describe a novel set of interaction techniques that make it easier to explore and interpret such pathways. Specifically, our application allows neuroscientists to place and interactively manipulate box-shaped regions (or volumes of interest) to selectively display pathways that pass through specific anatomical areas. A simple and flexible query language allows for arbitrary combinations of these queries using Boolean logic operators. Queries can be further restricted by numerical path properties such as length, mean fractional anisotropy, and mean curvature. By precomputing the pathways and their statistical properties, we obtain the speed necessary for interactive question-and-answer sessions with brain researchers. We survey some questions that researchers have been asking about tractography data and show how our system can be used to answer these questions efficiently.

We present a novel multiscale approach for flow visualization. We define a local alignment tensor that encodes a measure for alignment to the direction of a given flow field. This tensor induces an anisotropic differential operator on the flow domain, which is discretized with a standard finite element technique. The entries of the corresponding stiffness matrix represent the anisotropically weighted couplings of adjacent nodes of the domain mesh. We use an algebraic multigrid algorithm to generate a hierarchy of fine to coarse descriptions for the above coupling data. This hierarchy comprises a set of coarse grid nodes, a multiscale of basis functions and their corresponding supports. We use these supports to obtain a multilevel decomposition of the flow structure. Standard streamline icons are used to visualize this decomposition at any user-selected level of detail. The method provides a single framework for vector field decomposition independent on the domain dimension or mesh type. Applications are shown in 2D, for flow fields on curved surfaces, and for 3D volumetric flow fields.

Coronary heart disease (CHD) is the number one killer in the United States. Although it is well known that CHD mainly occurs due to blocked arteries, there are contradictory results from studies designed to identify basic causes for this common disease is. To find out more about the true reason for CHD, virtual models can be employed to better understand the way the heart functions. With such a model, scientists and surgeons are able to analyze the effects of different treatment options, and ultimately find more suited ways to prevent coronary heart diseases. To investigate a given model, appropriate navigation methods are required, including suitable input devices. For the visualization, graphics cards originally designed for gaming applications are used; so, it is a just natural transition to adapt gaming input devices to a visualization system for controlling of the navigation. These devices are usually well designed with respect to ergonomics and durability, yielding more degrees of freedom in steering than two-dimensional input devices, such as desktop mice. This poster describes a visualization system that provides the user with advanced control devices for navigation enabling interactive exploration of the model. Force-feedback and sound effects provide additional cues.

Most data used in the study of seafloor hydrothermal plumes consists of sonar (acoustic) scans and sensor readings. Visual data captures only a portion of the sonar data range due to the prohibitive cost and physical infeasibility of taking sufficient lighting and video equipment to such extreme depths. However, visual images are available from research dives and from the recent IMAX movie, volcanoes of the deep sea. In this application paper, we apply existing lighting models with forward scattering and light attenuation to the 3D sonar data in order to mimic the visual images available. These generated images are compared to existing visual images. This can help the geoscientists understand the relationship between these different data modalities and elucidate some of the mechanisms used to capture the data.

A common deficiency of discretized datasets is that detail beyond the resolution of the dataset has been irrecoverably lost. This lack of detail becomes immediately apparent once one attempts to zoom into the dataset and only recovers blur. We describe a method that generates the missing detail from any available and plausible high-resolution data, using texture synthesis. Since the detail generation process is guided by the underlying image or volume data and is designed to fill in plausible detail in accordance with the coarse structure and properties of the zoomed-in neighborhood, we refer to our method as constrained texture synthesis. Regular zooms become "semantic zooms", where each level of detail stems from a data source attuned to that resolution. We demonstrate our approach by a medical application - the visualization of a human liver - but its principles readily apply to any scenario, as long as data at all resolutions are available. We first present a 2D viewing application, called the "virtual microscope", and then extend our technique to 3D volumetric viewing.