DevLan/vispubs huggingface dataset:
Semi-immersive space mission design and visualization: case study of the "Terrestrial Planet Finder" mission
Authors: Ken Museth, Alan H. Barr, Martin W. Lo
Published at Vis, 2001

The paper addresses visualization issues of the Terrestrial Planet Finder Mission (C.A. Beichman et al., 1999). The goal of this mission is to search for chemical signatures of life in distant solar systems using five satellites flying in formation to simulate a large telescope. To design and visually verify such a delicate mission, one has to analyze and interact with many different 3D spacecraft trajectories, which is often difficult in 2D. We employ a novel trajectory design approach using invariant manifold theory, which is best understood and utilized in an immersive setting. The visualization also addresses multi-scale issues related to the vast differences in distance, velocity, and time at different phases of the mission. Additionally, the parameterization and coordinate frames used for numerical simulations may not be suitable for direct visualization. Relative motion presents a more serious problem where the patterns of the trajectories can only be viewed in particular rotating frames. Some of these problems are greatly relieved by using interactive, animated stereo 3D visualization in a semi-immersive environment such as a Responsive Workbench. Others were solved using standard techniques such as a stratify approach with multiple windows to address the multiscale issues, re-parameterizations of trajectories and associated 2D manifolds and relative motion of the camera to "evoke" the desired patterns.
Simplicial subdivisions and sampling artifacts
Authors: Hamish A. Carr, Torsten Möller, Jack Snoeyink
Published at Vis, 2001

We review several schemes for dividing cubical cells into simplices (tetrahedra) in 3-D for interpolating from sampled data to R/sup 3/ or for computing isosurfaces by barycentric interpolation. We present test data that reveal the geometric artifacts that these subdivision schemes generate, and discuss how these artifacts relate to the filter kernels that correspond to the subdivision schemes.
Smooth approximation and rendering of large scattered data sets
Authors: Jörg Haber, Frank Zeilfelder, Oleg Davydov, Hans-Peter Seidel
Published at Vis, 2001

Presents an efficient method to automatically compute a smooth approximation of large functional scattered data sets given over arbitrarily shaped planar domains. Our approach is based on the construction of a C/sup 1/-continuous bivariate cubic spline and our method offers optimal approximation order. Both local variation and nonuniform distribution of the data are taken into account by using local polynomial least squares approximations of varying degree. Since we only need to solve small linear systems and no triangulation of the scattered data points is required, the overall complexity of the algorithm is linear in the total number of points. Numerical examples dealing with several real-world scattered data sets with up to millions of points demonstrate the efficiency of our method. The resulting spline surface is of high visual quality and can be efficiently evaluated for rendering and modeling. In our implementation we achieve real-time frame rates for typical fly-through sequences and interactive frame rates for recomputing and rendering a locally modified spline surface.
Surgical simulator for hysteroscopy: a case study of visualization in surgical training
Authors: Kevin Montgomery, Wm. LeRoy Heinrichs, Cynthia Bruyns, Simon Wildermuth, Christopher J. Hasser, Stephanie Ozenne, David Bailey
Published at Vis, 2001

Computer-based surgical simulation promises to provide a broader scope of clinical training through the introduction of anatomic variation, simulation of untoward events, and collection of performance data. We present a haptically-enabled surgical simulator for the most common techniques in diagnostic and operative hysteroscopy-cervical dilation, endometrial resection and ablation, and lesion excision. Engineering tradeoffs in developing a real-time, haptic-rate simulator are discussed.
Texture Hardware Assisted Rendering of Time-Varying Volume Data
Authors: Eric B. Lum, Kwan-Liu Ma, John P. Clyne
Published at Vis, 2001

In this paper we present a hardware-assisted rendering technique coupled with a compression scheme for the interactive visual exploration of time-varying scalar volume data. A palette-based decoding technique and an adaptive bit allocation scheme are developed to fully utilize the texturing capability of a commodity 3-D graphics card. Using a single PC equipped with a modest amount of memory, a texture capable graphics card, and an inexpensive disk array, we are able to render hundreds of time steps of regularly gridded volume data (up to 45 millions voxels each time step) at interactive rates, permitting the visual exploration of large scientific data sets in both the temporal and spatial domain.
The "Which Blair project": a quick visual method for evaluating perceptual color maps
Authors: Bernice E. Rogowitz, Alan D. Kalvin
Published at Vis, 2001

We have developed a fast, perceptual method for selecting color scales for data visualization that takes advantage of our sensitivity to luminance variations in human faces. To do so, we conducted experiments in which we mapped various color scales onto the intensity values of a digitized photograph of a face and asked observers to rate each image. We found a very strong correlation between the perceived naturalness of the images and the degree to which the underlying color scales increased monotonically in luminance. Color scales that did not include a monotonically increasing luminance component produced no positive rating scores. Since color scales with monotonic luminance profiles are widely recommended for visualizing continuous scalar data, a purely visual technique for identifying such color scales could be very useful, especially in situations where color calibration is not integrated into the visualization environment, such as over the Internet.
The MetVR case study: meteorological visualization in an immersive virtual environment
Authors: Sean Ziegeler, Robert J. Moorhead II, Paul J. Croft, Duanjun Lu
Published at Vis, 2001

Traditional methods for displaying weather products are generally two-dimensional (2D) plots or just text format. It is hard for forecasters to get the entire picture of the atmosphere using these methods. The problems apparent in 2D with comparing and correlating multiple layers are overcome simply by adding a dimension. This is important because pertinent features in the data sets may lie in multiple layers and span several time steps. However, simply using a three-dimensional (3D) approach is not enough. The capacity for analysis of small-scale, but important, features in 2D are lost when transitioning to 3D. We propose that 3D's advantages can be incorporated with 2D's small-scale analysis by using an immersive virtual environment. In this case study, we evaluate our current standing with the project: have we met our goals, and how should we proceed from this point? To evaluate our application, we invited meteorologists to use the application to explore a data set. Then we presented our goals and asked which ones had we met, from a meteorologist's perspective. The results qualitatively reflected that our application was effective and further research would be worthwhile.
The perspective shear-warp algorithm in a virtual environment
Authors: Jürgen P. Schulze, Roland Niemeier, Ulrich Lang 0002
Published at Vis, 2001

Since the original paper of Lacroute and Levoy (1994), where the shear-warp factorization was also shown for perspective projections, a lot of work has been carried out using the shear-warp factorization with parallel projections. However, none of it has proved or improved the algorithm for the perspective projection. Also in Lacroute's Volpack library, the perspective shear-warp volume rendering algorithm is missing. This paper reports on an implementation of the perspective shear-warp algorithm, which includes enhancements for its application in immersive virtual environments. Furthermore, a mathematical proof for the correctness of the permutation of projection and warp is provided, so far a basic assumption of the shear-warp perspective projection.
Transport and anisotropic diffusion in time-dependent flow visualization
Authors: David Bürkle, Tobias Preußer, Martin Rumpf
Published at Vis, 2001

The visualization of time-dependent flow is an important and challenging topic in scientific visualization. Its aim is to represent transport phenomena governed by time-dependent vector fields in an intuitively understandable way, using images and animations. Here we pick up the recently presented anisotropic diffusion method, expand and generalize it to allow a multiscale visualization of long-term, complex transport problems. Instead of streamline type patterns generated by the original method now streakline patterns are generated and advected. This process obeys a nonlinear transport diffusion equation with typically dominant transport. Starting from some noisy initial image, the diffusion actually generates and enhances patterns which are then transported in the direction of the flow field. Simultaneously the image is again sharpened in the direction orthogonal to the flow field. A careful adjustment of the models parameters is derived to balance diffusion and transport effects in a reasonable way. Properties of the method can be discussed for the continuous model, which is solved by an efficient upwind finite element discretization. As characteristic for the class of multiscale image processing methods, we can in advance select a suitable scale for representing the flow field.
Undersampling and oversampling in sample based shape modeling
Authors: Tamal K. Dey, Joachim Giesen, Samrat Goswami, James Hudson, Rephael Wenger, Wulue Zhao
Published at Vis, 2001

Shape modeling is an integral part of many visualization problems. Recent advances in scanning technology and a number of surface reconstruction algorithms have opened up a new paradigm for modeling shapes from samples. Many of the problems currently faced in this modeling paradigm can be traced back to two anomalies in sampling, namely undersampling and oversampling. Boundaries, non-smoothness and small features create undersampling problems, whereas oversampling leads to too many triangles. We use Voronoi cell geometry as a unified guide to detect undersampling and oversampling. We apply these detections in surface reconstruction and model simplification. Guarantees of the algorithms can be proved. The authors show the success of the algorithms empirically on a number of interesting data sets.
User-centric viewpoint computation for haptic exploration and manipulation
Authors: Miguel A. Otaduy, Ming C. Lin
Published at Vis, 2001

We present several techniques for user-centric viewing of the virtual objects or datasets under haptic exploration and manipulation. Depending on the type of tasks performed by the user, our algorithms compute automatic placement of the user viewpoint to navigate through the scene, to display the near-optimal views, and to reposition the viewpoint for haptic visualization. This is accomplished by conjecturing the user's intent based on the user's actions, the object geometry, and intra- and inter-object occlusion relationships. These algorithms have been implemented and interfaced with both a 3-DOF and a 6-DOF PHANToM arms. We demonstrate their application on haptic exploration and visualization of a complex structure, as well as multiresolution modeling and 3D painting with a haptic interface.
Variational classification for visualization of 3D ultrasound data
Authors: Raanan Fattal, Dani Lischinski
Published at Vis, 2001

We present a new technique for visualizing surfaces from 3D ultrasound data. 3D ultrasound datasets are typically fuzzy, contain a substantial amount of noise and speckle, and suffer from several other problems that make extraction of continuous and smooth surfaces extremely difficult. We propose a novel opacity classification algorithm for 3D ultrasound datasets, based on the variational principle. More specifically, we compute a volumetric opacity function that optimally satisfies a set of simultaneous requirements. One requirement makes the function attain nonzero values only in the vicinity of a user-specified value, resulting in soft shells of finite, approximately constant thickness around isosurfaces in the volume. Other requirements are designed to make the function smoother and less sensitive to noise and speckle. The computed opacity function lends itself well to explicit geometric surface extraction, as well as to direct volume rendering at interactive rates. We also describe a new splatting algorithm that is particularly well suited for displaying soft opacity shells. Several examples and comparisons are included to illustrate our approach and demonstrate its effectiveness on real 3D ultrasound datasets.
Virtual Temporal Bone Dissection: A Case Study
Authors: Jason Bryan, Don Stredney, Gregory J. Wiet, Dennis Sessanna
Published at Vis, 2001

The Temporal Bone Dissection Simulator is an ongoing research project for the construction of a synthetic environment suitable for virtual dissection of human temporal bone and related anatomy. Funded by the National Institute on Deafness and Other Communication Disorders (NIDCD), the primary goal of this project is to provide a safe, robust, and cost-effective virtual environment for learning the anatomy and surgical procedures associated with the temporal bone. Direct volume visualization has been indispensable for the necessary level of realism and interactivity that is vital to the success of this project. This work is being conducted by the Ohio Supercomputer Center in conjunction with the Department of Otolaryngology at the Ohio State University, and NIDCD.
Visualization and interaction techniques for the exploration of vascular structures
Authors: Horst K. Hahn, Bernhard Preim, Dirk Selle, Heinz-Otto Peitgen
Published at Vis, 2001

We describe a pipeline of image processing steps for deriving symbolic models of vascular structures from radiological data which reflect the branching pattern and diameter of vessels. For the visualization of these symbolic models, concatenated truncated cones are smoothly blended at branching points. We put emphasis on the quality of the visualizations which is achieved by anti-aliasing operations in different stages of the visualization. The methods presented are referred to as HQVV (high quality vessel visualization). Scalable techniques are provided to explore vascular structures of different orders of magnitude. The hierarchy as well as the diameter of the branches of vascular systems are used to restrict visualizations to relevant subtrees and to emphasize parts of vascular systems. Our research is inspired by clear visualizations in textbooks and is targeted toward medical education and therapy planning. We describe the application of vessel visualization techniques for liver surgery planning. For this application it is crucial to recognize the morphology and branching pattern of vascular systems as well as the basic spatial relations between vessels and other anatomic structures.
Visualization of large terrains made easy
Authors: Peter Lindstrom 0001, Valerio Pascucci
Published at Vis, 2001

We present an elegant and simple to implement framework for performing out-of-core visualization and view-dependent refinement of large terrain surfaces. Contrary to the trend of increasingly elaborate algorithms for large-scale terrain visualization, our algorithms and data structures have been designed with the primary goal of simplicity and efficiency of implementation. Our approach to managing large terrain data also departs from more conventional strategies based on data tiling. Rather than emphasizing how to segment and efficiently bring data in and out of memory, we focus on the manner in which the data is laid out to achieve good memory coherency for data accesses made in a top-down (coarse-to-fine) refinement of the terrain. We present and compare the results of using several different data indexing schemes, and propose a simple to compute index that yields substantial improvements in locality and speed over more commonly used data layouts. Our second contribution is a new and simple, yet easy to generalize method for view-dependent refinement. Similar to several published methods in this area, we use longest edge bisection in a top-down traversal of the mesh hierarchy to produce a continuous surface with subdivision connectivity. In tandem with the refinement, we perform view frustum culling and triangle stripping. These three components are done together in a single pass over the mesh. We show how this framework supports virtually any error metric, while still being highly memory and compute efficient.
Visualization of Sports using Motion Trajectories: Providing Insights into Performance, Style, and Strategy
Authors: Gopal Sarma Pingali, Agata Opalach, Yves Jean, Ingrid Carlbom
Published at Vis, 2001

Remote experience of sporting events has thus far been limited mostly to watching video and the scores and statistics associated with the sport. However, a fast-developing trend is the use of visualization techniques to give new insights into performance, style, and strategy of the players. Automated techniques can extract accurate information from video about player performance that not even the most skilled observer is able to discern. When presented as static images or as a three-dimensional virtual replay, this information makes viewing a game an entirely new and exciting experience. This paper presents one such sports visualization system called LucentVision, which has been developed for the sport of tennis. LucentVision uses real-time video analysis to obtain motion trajectories of players and the ball, and offers a rich set of visualization options based on this trajectory data. The system has been used extensively in the broadcast of international tennis tournaments, both on television and the Internet.
Visualizing 2D probability distributions from EOS satellite image-derived data sets: a case study
Authors: David L. Kao, Jennifer L. Dungan, Alex T. Pang
Published at Vis, 2001

Maps of biophysical and geophysical variables using Earth Observing System (EOS) satellite image data are an important component of Earth science. These maps have a single value derived at every grid cell and standard techniques are used to visualize them. Current tools fall short, however, when it is necessary to describe a distribution of values at each grid cell. Distributions may represent a frequency of occurrence over time, frequency of occurrence from multiple runs of an ensemble forecast or possible values from an uncertainty model. We identify these "distribution data sets" and present a case study to visualize such 2D distributions. Distribution data sets are different from multivariate data sets in the sense that the values are for a single variable instead of multiple variables. Data for this case study consists of multiple realizations of percent forest cover, generated using a geostatistical technique that combines ground measurements and satellite imagery to model uncertainty about forest cover. We present two general approaches for analyzing and visualizing such data sets. The first is a pixel-wise analysis of the probability density functions for the 2D image while the second is an analysis of features identified within the image. Such pixel-wise and feature-wise views will give Earth scientists a more complete understanding of distribution data sets. See www.cse.ucsc.edu/research/avis/nasa is for additional information.
Volume Rendering of Fine Details Within Medical Data
Authors: Feng Dong 0005, Gordon Clapworthy, Mel Krokos
Published at Vis, 2001

Presents a method concerning the volume rendering of fine details, such as blood vessels and nerves, from medical data. The realistic and efficient visualization of such structures is often of great medical interest, and conventional rendering techniques do not always deal with them adequately. Our method uses preprocessing to reconstruct fine details that are difficult to segment and label. It detects the presence of fine geometrical structures, such as cracks or cylinders that suggest the existence of, for example, blood vessels or nerves; the subsequent volume rendering then displays fine geometrical objects that lie on a surface. The method can also show structures within the volume, using a special "integration sampling" scheme to portray reconstructed volume texture, such as that exhibited by muscle fibers. By combining the surface structure and volume texture in the rendering, realistic results can be produced; examples are provided.
Wavelet representation of contour sets
Authors: Martin Hering-Bertram, Daniel E. Laney, Mark A. Duchaineau, Charles D. Hansen, Bernd Hamann, Kenneth I. Joy
Published at Vis, 2001

We present a new wavelet compression and multiresolution modeling approach for sets of contours (level sets). In contrast to previous wavelet schemes, our algorithm creates a parametrization of a scalar field induced by its contours and compactly stores this parametrization rather than function values sampled on a regular grid. Our representation is based on hierarchical polygon meshes with subdivision connectivity whose vertices are transformed into wavelet coefficients. From this sparse set of coefficients, every set of contours can be efficiently reconstructed at multiple levels of resolution. When applying lossy compression, introducing high quantization errors, our method preserves contour topology, in contrast to compression methods applied to the corresponding field function. We provide numerical results for scalar fields defined on planar domains. Our approach generalizes to volumetric domains, time-varying contours, and level sets of vector fields.
Wind Tunnel Data Fusion and Immersive Visualization: A Case Study
Authors: Kurt Severance, Paul Brewster, Barry Lazos, Daniel F. Keefe
Published at Vis, 2001

This case study describes the process of fusing the data from several wind tunnel experiments into a single coherent visualization. Each experiment was conducted independently and was designed to explore different flow features around airplane landing gear. In the past, it would have been very difficult to correlate results from the different experiments. However, with a single 3-D visualization representing the fusion of the three experiments, significant insight into the composite flowfield was observed that would have been extremely difficult to obtain by studying its component parts. The results are even more compelling when viewed in an immersive environment.
2D vs 3D, implications on spatial memory
Authors: Monica Tavanti, Mats Lind
Published at InfoVis, 2001

Since the introduction of graphical user interfaces (GUI) and two-dimensional (2D) displays, the concept of space has entered the information technology (IT) domain. Interactions with computers were re-encoded in terms of fidelity to the interactions with real environment and consequently in terms of fitness to cognitive and spatial abilities. A further step in this direction was the creation of three-dimensional (3D) displays which have amplified the fidelity of digital representations. However, there are no systematic results evaluating the extent to which 3D displays better support cognitive spatial abilities. The aim of this research is to empirically investigate spatial memory performance across different instances of 2D and 3D displays. Two experiments were performed. The displays used in the experimental situation represented hierarchical information structures. The results of the test show that the 3D display does improve performances in the designed spatial memory task.