DevLan/vispubs huggingface dataset:
CAVEvis: distributed real-time visualization of time-varying scalar and vector fields using the CAVE virtual reality theater
Authors: Vijendra Jaswal
Published at Vis, 1997

The paper discusses CAVEvis and a related set of tools for the interactive visualization and exploration of large sets of time-varying scalar and vector fields using the CAVE virtual reality environment. Since visualization of large data sets can be very time-consuming in both computation and rendering time, the task is distributed over multiple machines, each of which is specialized for some aspect of the visualization process. All modules must run asynchronously to maintain the highest level of interactivity. A model of distributed visualization is introduced that addresses important issues related to the management of time-dependent data, module synchronization, and interactivity bottlenecks.
Collaborative augmented reality: exploring dynamical systems
Authors: Anton L. Fuhrmann, Helwig Löffelmann, Dieter Schmalstieg
Published at Vis, 1997

We present collaborative scientific visualization in STUDIERSTUBE. STUDIERSTUBE is an augmented reality system that has several advantages over conventional desktop and other virtual reality environments, including true stereoscopy, 3D-interaction, individual viewpoints and customized views for multiple users, unhindered natural collaboration and low cost. We demonstrate the application of this concept for the interaction of multiple users and illustrate it with several visualizations of dynamical systems in DynSys3D, a visualization system running on top of AVS.
Collaborative visualization
Authors: Jason D. Wood, Helen Wright, Ken Brodlie
Published at Vis, 1997

Current visualization systems are designed around a single user model, making it awkward for large research teams to collectively analyse large data sets. The paper shows how the popular data flow approach to visualization can be extended to allow multiple users to collaborate-each running their own visualization pipeline but with the opportunity to connect in data generated by a colleague, Thus collaborative visualizations are 'programmed' in exactly the same 'plug-and-play' style as is now customary for single-user mode. The paper describes a system architecture that can act as a basis for the collaborative extension of any data flow visualization system, and the ideas are demonstrated through a particular implementation in terms of IRIS Explorer.
Collision detection for volumetric objects
Authors: Taosong He, Arie E. Kaufman
Published at Vis, 1997

We propose a probability model for the handling of complicated interactions between volumetric objects. In our model each volume is associated with a "probability map" that assigns a "surface crossing" probability to each space point according to local volume properties. The interaction between two volumes is then described by finding the intersecting regions between the volumes, and calculating the "collision probabilities" at each intersecting point from the surface crossing probabilities. To enable fast and efficient calculations, we introduce the concept of a distance map and develop two hierarchical collision detection algorithms, taking advantage of the uniform structure of volumetric datasets.
Computing the separating surface for segmented data
Authors: Gregory M. Nielson, Richard Franke
Published at Vis, 1997

An algorithm for computing a triangulated surface which separates a collection of data points that have been segmented into a number of different classes is presented. The problem generalizes the concept of an isosurface which separates data points that have been segmented into only two classes: those for which data function values are above the threshold and those which are below the threshold value. The algorithm is very simple, easy to implement and applies without limit to the number of classes.
Constrained 3D navigation with 2D controllers
Authors: Andrew J. Hanson, Eric A. Wernert
Published at Vis, 1997

Navigation through 3D spaces is required in many interactive graphics and virtual reality applications. The authors consider the subclass of situations in which a 2D device such as a mouse controls smooth movements among viewpoints for a "through the screen" display of a 3D world. Frequently, there is a poor match between the goal of such a navigation activity, the control device, and the skills of the average user. They propose a unified mathematical framework for incorporating context-dependent constraints into the generalized viewpoint generation problem. These designer-supplied constraint modes provide a middle ground between the triviality of a single camera animation path and the confusing excess freedom of common unconstrained control paradigms. They illustrate the approach with a variety of examples, including terrain models, interior architectural spaces, and complex molecules.
Controlled simplification of genus for polygonal models 
Authors: Jihad El-Sana, Amitabh Varshney
Published at Vis, 1997

Genus-reducing simplifications are important in constructing multiresolution hierarchies for level-of-detail-based rendering, especially for datasets that have several relatively small holes, tunnels, and cavities. We present a genus-reducing simplification approach that is complementary to the existing work on genus-preserving simplifications. We propose a simplification framework in which genus-reducing and genus-preserving simplifications alternate to yield much better multiresolution hierarchies than would have been possible by using either one of them. In our approach we first identify the holes and the concavities by extending the concept of /spl alpha/-hulls to polygonal meshes under the L/sub /spl infin// distance metric and then generate valid triangulations to fill them.
Determination of unknown particle charges in a thunder cloud based upon detected electric field vectors
Authors: Dan Drake, Thomas Simpson, Larry Smithmier, Penny Rheingans
Published at Vis, 1997

Climatological data about thunderstorms is traditionally collected by balloons or planes traveling through the storm along straight tracts. Such data lends itself to simple 2D representations. The data described in this paper was gathered by a sail plane spiraling in an updraft within a thundercloud. The more complex organization of data samples demands more complex representation methods. This paper describes a system developed using the Visualization Toolkit (VTK) to explore such data. The data consists of several scalar values and a set of vector values associated with positional data on the measuring devices. The goal of this visualization is to explore the location of point charges suggested by the electromagnetic field vectors and determine if any correlation exists between the point charge location and standard cloud microstructure scalar measurements such as temperature. There are several problems associated with visualizing this rather unique set of data. They stem from the fact that the data is a sparse spiraling sample of scalars and vectors. The system allows the track of the plane to be displayed as a line, a tube or a ribbon; scalar values can be displayed as transparent isosurfaces; and the vector data as an arrow plot along that track, given a color that is constant, based on orientation or related to the value of a scalar. Any combination of methods can be used to display the data. A single primitive can be overloaded in many ways, or several different variables can all be displayed simultaneously.
Displaying data in multidimensional relevance space with 2D visualization maps
Authors: Jackie Assa, Daniel Cohen-Or, Tova Milo
Published at Vis, 1997

The paper introduces a tool for visualizing a multidimensional relevance space. Abstractly, the information to be displayed consists of a large number of objects, a set of features that are likely to be of interest to the user, and some function that measures the relevance level of every object to the various features. The goal is to provide the user with a concise and comprehensible visualization of that information. For the type of applications concentrated on, the exact relevance measures of the objects are not significant. This enables accuracy to be traded for a clearer display. The idea is to "flatten" the multidimensionality of the feature space into a 2D "relevance map", capturing the inter-relations among the features, without causing too many ambiguous interpretations of the results. To better reflect the nature of the data and to resolve the ambiguity the authors refine the given set of features and introduce the notion of composed features. The layout of the map is then obtained by grading it according to a set of rules and using a simulated annealing algorithm which optimizes the layout with respect to these rules. The technique proposed has been implemented and tested, in the context of visualizing the result of a Web search, in the RMAP (Relevance Map) prototype system.
DNA visual and analytic data mining
Authors: Patrick Hoffman, Georges G. Grinstein, Kenneth A. Marx, Ivo Grosse, Eugene Stanley
Published at Vis, 1997

Describes data exploration techniques designed to classify DNA sequences. Several visualization and data mining techniques were used to validate and attempt to discover new methods for distinguishing coding DNA sequences (exons) from non-coding DNA sequences (introns). The goal of the data mining was to see whether some other, possibly non-linear combination of the fundamental position-dependent DNA nucleotide frequency values could be a better predictor than the AMI (average mutual information). We tried many different classification techniques including rule-based classifiers and neural networks. We also used visualization of both the original data and the results of the data mining to help verify patterns and to understand the distinction between the different types of data and classifications. In particular, the visualization helped us develop refinements to neural network classifiers, which have accuracies as high as any known method. Finally, we discuss the interactions between visualization and data mining and suggest an integrated approach.
Dynamic color mapping of bivariate qualitative data
Authors: Penny Rheingans
Published at Vis, 1997

Color is widely and reliably used to display the value of a single scalar variable. It is more rarely, and far less reliably, used to display multivariate data. Dynamic control over the parameters of the color mapping results in a more effective environment for the exploration of multivariate spatial distributions. The paper describes an empirical study comparing the effectiveness of static versus dynamic representations for the exploration of qualitative aspects of bivariate distributions. In this experiment, subjects made judgments about the correspondence of the shape, location, and magnitude of two patterns under conditions with varying amounts of random noise. Subjects made significantly more correct judgements (p&lt;0.001) about feature shape and relative positions using the dynamic representation, on average forty-five percent more. The differences between static and dynamic representations were greater in the presence of noise.
Dynamic smooth subdivision surfaces for data visualization
Authors: Chhandomay Mandal, Hong Qin, Baba C. Vemuri
Published at Vis, 1997

Recursive subdivision schemes have been extensively used in computer graphics and scientific visualization for modeling smooth surfaces of arbitrary topology. Recursive subdivision generates a visually pleasing smooth surface in the limit from an initial user-specified polygonal mesh through the repeated application of a fixed set of subdivision rules. In this paper, we present a new dynamic surface model based on the Catmull-Clark (1978) subdivision scheme, which is a very popular method to model complicated objects of arbitrary genus because of many of its nice properties. Our new dynamic surface model inherits the attractive properties of the Catmull-Clark subdivision scheme as well as that of the physics-based modeling paradigm. This new model provides a direct and intuitive means of manipulating geometric shapes, a fast, robust and hierarchical approach for recovering complex geometric shapes from range and volume data using very few degrees of freedom (control vertices). We provide an analytic formulation and introduce the physical quantities required to develop the dynamic subdivision surface model which can be interactively deformed by applying synthesized forces in real time. The governing dynamic differential equation is derived using Lagrangian mechanics and a finite element discretization. Our experiments demonstrate that this new dynamic model has a promising future in computer graphics, geometric shape design and scientific visualization.
Efficient subdivision of finite-element datasets into consistent tetrahedra
Authors: Guy Albertelli, Roger Crawfis
Published at Vis, 1997

The paper discusses the problem of subdividing unstructured mesh topologies containing hexahedra, prisms, pyramids and tetrahedra into a consistent set of only tetrahedra, while preserving the overall mesh topology. Efficient algorithms for volume rendering, iso-contouring and particle advection exist for mesh topologies comprised solely of tetrahedra. General finite-element simulations however, consist mainly of hexahedra, and possibly prisms, pyramids and tetrahedra. Arbitrary subdivision of these mesh topologies into tetrahedra can lead to discontinuous behaviour across element faces. This will show up as visible artifacts in the iso-contouring and volume rendering algorithms, and lead to impossible face adjacency graphs for many algorithms. The authors present various properties of tetrahedral subdivisions, and an algorithm SOP determining a consistent subdivision containing a minimal set of tetrahedra.
Extracting feature lines from 3D unstructured grids
Authors: Kwan-Liu Ma, Victoria Interrante
Published at Vis, 1997

The paper discusses techniques for extracting feature lines from three-dimensional unstructured grids. The twin objectives are to facilitate the interactive manipulation of these typically very large and dense meshes, and to clarify the visualization of the solution data that accompanies them. The authors describe the perceptual importance of specific viewpoint-dependent and view-independent features, discuss the relative advantages and disadvantages of several alternative algorithms for identifying these features (taking into consideration both local and global criteria), and demonstrate the results of these methods on a variety of different data sets.
exVis: developing a wind tunnel data visualization tool
Authors: Samuel P. Uselton
Published at Vis, 1997

Software has been developed to apply visualization techniques to aeronautics data collected during wind tunnel experiments. Interaction between the software developers and the aeroscientists has been crucial in making the software. The interaction has also been important in building the scientists' confidence in the use of interactive, computer-mediated analysis tools.
Fast oriented line integral convolution for vector field visualization via the Internet
Authors: Rainer Wegenkittl, M. Eduard Gröller
Published at Vis, 1997

Oriented line integral convolution (OLIC) illustrates flow fields by convolving a sparse texture with an anisotropic convolution kernel. The kernel is aligned to the underlying flow of the vector field. OLIC does not only show the direction of the flow but also its orientation. The paper presents fast rendering of oriented line integral convolution (FROLIC), which is approximately two orders of magnitude faster than OLIC. Costly convolution operations as done in OLIC are replaced in FROLIC by approximating a streamlet through a set of disks with varying intensity. The issue of overlapping streamlets is discussed. Two efficient animation techniques for animating FROLIC images are described. FROLIC has been implemented as a Java applet. This allows researchers from various disciplines (typically with inhomogenous hardware environments) to conveniently explore and investigate analytically defined 2D vector fields.
GADGET: goal-oriented application design guidance for modular visualization environments
Authors: Issei Fujishiro, Yuriko Takeshima, Yoshihiko Ichikawa, Kyoko Nakamura
Published at Vis, 1997

Modular visualization environments (MVEs) have recently been regarded as the de facto standard for scientific data visualization, mainly due to adoption of the visual programming style, reusability, and extendability. However, since scientists and engineers as the MVE principal user are not always familiar with how to map numerical data to proper graphical primitives, the set of built-in modules is not fully used to construct necessary application networks. Therefore, a certain mechanism needs to be incorporated into MVEs, which makes use of heuristics and expertise of visualization specialists (visineers), and which supports the user in designing his/her applications with MVEs. The Wehrend's goal-oriented taxonomy of visualization techniques is adopted as the basic philosophy to develop a system, called GADGET, for application design guidance for MVEs. The GADGET system interactively helps the user design appropriate applications according to the specific visualization goals, temporal efficiency versus accuracy requirements, and such properties as dimension and mesh type of a given target dataset. Also the GADGET system is capable of assisting the user in customizing a prototype modular network for his/her desired applications by showing execution examples involving datasets of the same type. The paper provides an overview of the GADGET guidance mechanism and system architecture, with an emphasis on its knowledge base design. Sample data visualization problems are used to demonstrate the usefulness of the GADGET system.
Haar wavelets over triangular domains with applications to multiresolution models for flow over a sphere
Authors: Gregory M. Nielson, Il-Hong Jung, Junwon Sung
Published at Vis, 1997

Some new piecewise constant wavelets defined over nested triangulated domains are presented and applied to the problem of multiresolution analysis of flow over a spherical domain. These new, nearly orthogonal wavelets have advantages over the existing weaker biorthogonal wavelets. In the planar case of uniform areas, the wavelets converge to one of two fully orthogonal Haar wavelets. These new, fully orthogonal wavelets are proven to be the only possible wavelets of this type.
I/O optimal isosurface extraction
Authors: Yi-Jen Chiang, Cláudio T. Silva
Published at Vis, 1997

The authors give I/O-optimal techniques for the extraction of isosurfaces from volumetric data, by a novel application of the I/O-optimal interval tree of Arge and Vitter (1996). The main idea is to preprocess the data set once and for all to build an efficient search structure in disk, and then each time one wants to extract an isosurface, they perform an output-sensitive query on the search structure to retrieve only those active cells that are intersected by the isosurface. During the query operation, only two blocks of main memory space are needed, and only those active cells are brought into the main memory, plus some negligible overhead of disk accesses. This implies that one can efficiently visualize very large data sets on workstations with just enough main memory to hold the isosurfaces themselves. The implementation is delicate but not complicated. They give the first implementation of the I/O-optimal interval tree, and also implement their methods as an I/O filter for Vtk's isosurface extraction for the case of unstructured grids. They show that, in practice, the algorithms improve the performance of isosurface extraction by speeding up the active-cell searching process so that it is no longer a bottleneck. Moreover, this search time is independent of the main memory available. The practical efficiency of the techniques reflects their theoretical optimality.
Image synthesis from a sparse set of views
Authors: Qian Chen 0022, Gérard G. Medioni
Published at Vis, 1997

The authors present an image synthesis methodology and a system built around it. Given a sparse set of photographs taken from unknown viewpoints, the system generates images from new, different viewpoints with correct perspective, and handles occlusion. It achieves this without requiring any knowledge about the 3D structure of the scene nor the intrinsic camera parameters. The photo-realistic rendering process is polygon based and can be potentially implemented as real time texture mapping. The system is robust to noise by taking advantage of duplicate information from multiple views. They present results on several example scenes.
Information Exploration Shootout Project And Benchmark Data Sets: Evaluating How Visualization Does In Analyzing Real-World Data Analysis Problems
Authors: Georges G. Grinstein, Sharon J. Laskowski, Graham J. Wills, Bernice E. Rogowitz
Published at Vis, 1997

The convergence of database systems, knowledge discovery, anti visualization will have a fundamental impact on our capability to mine information and knowledge from very large databases. An enhanced data exploration capability has immediate applications to business and commerce, decision systems, information management, the intelligence community, and communication in the form of both on-line services and the World Wide Web. It holds the promise of major cost savings and increased revenues. Data mining now draws from fields including databases, statistics, information technology, data visualization, and artificial intelligence, especially knowledge-based systems. However, there is a clear sense that, to achieve the next increase in knowledge exploitation, these data exploration approaches must work together.
Instructional software for visualizing optical phenomena
Authors: David C. Banks, John T. Foley, Kiril Vidimce, Ming-Hoe Kiu
Published at Vis, 1997

We describe a multidisciplinary effort for creating interactive 3D graphical modules for visualizing optical phenomena. These modules are designed for use in an upper-level undergraduate course. The modules are developed in Open Inventor, which allows them to run under both Unix and Windows. The work is significant in that it applies contemporary interactive 3D visualization techniques to instructional courseware, which represents a considerable advance compared to the current state of the practice.
Integrated volume compression and visualization
Authors: Tzi-cker Chiueh, Chuan-Kai Yang, Taosong He, Hanspeter Pfister, Arie E. Kaufman
Published at Vis, 1997

Volumetric data sets require enormous storage capacity even at moderate resolution levels. The excessive storage demands not only stress the capacity of the underlying storage and communications systems, but also seriously limit the speed of volume rendering due to data movement and manipulation. A novel volumetric data visualization scheme is proposed and implemented in this work that renders 2D images directly from compressed 3D data sets. The novelty of this algorithm is that rendering is performed on the compressed representation of the volumetric data without pre-decompression. As a result, the overheads associated with both data movement and rendering processing are significantly reduced. The proposed algorithm generalizes previously proposed whole-volume frequency-domain rendering schemes by first dividing the 3D data set into subcubes, transforming each subcube to a frequency-domain representation, and applying the Fourier projection theorem to produce the projected 2D images according to given viewing angles. Compared to the whole-volume approach, the subcube-based scheme not only achieves higher compression efficiency by exploiting local coherency, but also improves the quality of resultant rendering images because it approximates the occlusion effect on a subcube by subcube basis.