Advanced interactive medical visualization on the GPU

Interactive visual analysis of a patient’s anatomy by means of computer-generated 3D imagery is crucial for diagnosis, pre-operative planning, and surgical training. The task of visualization is no longer limited to producing images at interactive rates, but also includes the guided extraction of significant features to assist the user in the data exploration process. An effective visualization module has to perform a problem-specific abstraction of the dataset, leading to a more compact and hence more efficient visual representation. Moreover, many medical applications, such as surgical training simulators and pre-operative planning for plastic and reconstructive surgery, require the visualization of datasets that are dynamically modified or even generated by a physics-based simulation engine.     

Advanced techniques for interactive visualization of multi‐resolution meshes

This paper addresses the problem of interactive visualization of multi‐resolution triangle meshes. Visible switching between different levels of detail is avoided by smoothly interpolating mesh geometry between different levels. The interpolation parameter is derived from the screen‐space geometric error of the affected mesh region instead of assigning a fixed time to the transition. The shortcomings of straightforward frame rate control mechanisms (i.e., overshooting and oscillation) are avoided by a semi‐predictive algorithm. The average rendering time per triangle is measured and used to determine the desired number of faces. A set of experiments demonstrates the advantages of both methods. Copyright © 2002 John Wiley & Sons, Ltd.     

Declarative language design for interactive visualization

We investigate the design of declarative, domain-specific languages for constructing interactive visualizations. By separating specification from execution, declarative languages can simplify development, enable unobtrusive optimization, and support retargeting across platforms. We describe the design of the Protovis specification language and its implementation within an object-oriented, statically-typed programming language (Java). We demonstrate how to support rich visualizations without requiring a toolkit-specific data model and extend Protovis to enable declarative specification of animated transitions. To support cross-platform deployment, we introduce rendering and event-handling infrastructures decoupled from the runtime platform, letting designers retarget visualization specifications (e.g., from desktop to mobile phone) with reduced effort. We also explore optimizations such as runtime compilation of visualization specifications, parallelized execution, and hardware-accelerated rendering. We present benchmark studies measuring the performance gains provided by these optimizations and compare performance to existing Java-based visualization tools, demonstrating scalability improvements exceeding an order of magnitude.     

Ambiguity-free edge-bundling for interactive graph visualization

Graph visualization has been widely used to understand and present both global structural and local adjacency information in relational data sets (e.g., transportation networks, citation networks, or social networks). Graphs with dense edges, however, are difficult to visualize because fast layout and good clarity are not always easily achieved. When the number of edges is large, edge bundling can be used to improve the clarity, but in many cases, the edges could be still too cluttered to permit correct interpretation of the relations between nodes. In this paper, we present an ambiguity-free edge-bundling method especially for improving local detailed view of a complex graph. Our method makes more efficient use of display space and supports detail-on-demand viewing through an interactive interface. We demonstrate the effectiveness of our method with public coauthorship network data.     

Highly interactive distributed visualization

We report on our iGrid2005 demonstration, called the “Dead Cat Demo”; an example of a highly interactive augmented reality application consisting of software services distributed over a wide-area, high-speed network. We describe our design decisions, analyse the implications of the design on application performance and show performance measurements.     

Style grammars for interactive visualization of architecture

Interactive visualization of architecture provides a way to quickly visualize existing or novel buildings and structures. Such applications require both fast rendering and an effortless input regimen for creating and changing architecture using high-level editing operations that automatically fill in the necessary details. Procedural modeling and synthesis is a powerful paradigm that yields high data amplification and can be coupled with fast-rendering techniques to quickly generate plausible details of a scene without much or any user interaction. Previously, forward generating procedural methods have been proposed where a procedure is explicitly created to generate particular content. In this paper, we present our work in inverse procedural modeling of buildings and describe how to use an extracted repertoire of building grammars to facilitate the visualization and quick modification of architectural structures and buildings. We demonstrate an interactive application where the user draws simple building blocks and, using our system, can automatically complete the building "in the style of other buildings using view-dependent texture mapping or nonphotorealistic rendering techniques. Our system supports an arbitrary number of building grammars created from user subdivided building models and captured photographs. Using only edit, copy, and paste metaphors, the entire building styles can be altered and transferred from one building to another in a few operations, enhancing the ability to modify an existing architectural structure or to visualize a novel building in the style of the others.     

Data parallel volume-rendering algorithms for interactive visualization

The increasing availability of parallel computing platforms has led to the development of parallel volume-rendering algorithms. In the present paper we compare two algorithms for volume raytracing in a data-parallel framework: a shearing technique and a line-drawing technique. The two algorithms are primarily distinguished by the level of parallelism they exploit. Both algorithms have been implemented on the Connection Machine CM2 massively parallel computer and execute at speeds suitable for interactive volume-rendering applications. Since considerable floating-point resources are available on the CM2, we have used rendering algorithms based on transport theory. In the second part of the paper we examine some of the tradeoffs involved between image quality and rendering speed when using high-fidelity rendering algorithms.     

Strategy-based interactive cluster visualization for information retrieval

In this paper we investigate a general purpose interactive information organization system. The system organizes documents by placing them into 1-, 2-, or 3-dimensional space based on their similarity and a spring-embedding algorithm. We begin by developing a method for estimating the quality of the organization when it is applied to a set of documents returned in response to a query. We show how the relevant documents tend to clump together in space. We proceed by presenting a method for measuring the amount of structure in the organization and explain how this knowledge can be used to refine the system. We also show that increasing the dimensionality of the organization generally improves its quality, albeit only a small amount. We introduce two methods for modifying the organization based on information obtained from the user and show how such feedback improves the organization. All the analysis is done offline without direct user intervention. Received: 21 December 1998 / Revised: 30 May 1999     

基于Web的PSE-Bio交互式可视化

PSE-Bio是一个基于Web服务面向生物信息学的问题求解平台。为了方便用户仅使用浏览器就能分析调用服务返回的结果,采用SVG技术实现基于WEB的可视化,设计了面向对象的统一可视化数据对象以封装调用不同Web服务返回的消息;设计了面向对象的可视化图形对象以利于交互可视化的实现;并用SVG脚本语言实现了用户与图形的交互以及可视化结果与服务的交互。实验结果表明,基于SVG的可视化方案能够满足生物信息数据的Web可视化需求。     

An interactive data visualization system

GRAFANA is an interactive program, which allows the user to produce drawings based on data stored on a disk file. The major advantage and originality of the system is that the user can interactively determine the visual effect of a drawing and immediately see it on the screen. Moreover, any drawing produced by GRAFANA can still be edited by a generalpurpose graphics editor. This system allows the user to obtain precisely the right drawing for any book, paper or report. GRAFANA has been implemented in MIRA-2D, a graphical Pascal extension. It is available for different machines and kinds of graphical devices.     

Distance visualization for interactive 3D implant planning

An instant and quantitative assessment of spatial distances between two objects plays an important role in interactive applications such as virtual model assembly, medical operation planning, or computational steering. While some research has been done on the development of distance-based measures between two objects, only very few attempts have been reported to visualize such measures in interactive scenarios. In this paper we present two different approaches for this purpose, and we investigate the effectiveness of these approaches for intuitive 3D implant positioning in a medical operation planning system. The first approach uses cylindrical glyphs to depict distances, which smoothly adapt their shape and color to changing distances when the objects are moved. This approach computes distances directly on the polygonal object representations by means of ray/triangle mesh intersection. The second approach introduces a set of slices as additional geometric structures, and uses color coding on surfaces to indicate distances. This approach obtains distances from a precomputed distance field of each object. The major findings of the performed user study indicate that a visualization that can facilitate an instant and quantitative analysis of distances between two objects in interactive 3D scenarios is demanding, yet can be achieved by including additional monocular cues into the visualization.     

An interactive FORTRAN program for three-dimensional molecular visualization

An interactive FORTRAN program executable in the VAX/VMS computer environment has been developed for three-dimensional molecular visualization on the Evans & Sutherland Picture System 390. The essential features of this program are described and the FORTRAN source code is available upon request.     

Multidimensional data analysis and visualization for time-dependent CFD problems

Programming and Computer Software - This paper is devoted to analysis and visualization of multidimensional data in problems of computational fluid dynamics (CFD). Multidimensional data are...     

Web-based dynamic and interactive environmental visualization

The development of novel interactive visualizations can substantially contribute to environmental modeling and understanding of complex environmental processes. To allow the Web Map Service (WMS) to support this, this paper explores a generic framework in which a dynamic environmental modeling process can be interactively visualized, controlled and tuned on the Internet by using Java 3D-based hybrid Internet computation through the simulation steering technique. A hydrological model, TOPMODEL, is employed to illustrate the simulation of a rainfall-run off process within a computational and steering environment. This environment allows users to visually interact and experiment with model computation, thereby facilitating the exploration of process-based environmental applications.     

MOLVIE: an interactive visualization environment for molecular structures

A Molecular visualization interactive environment (MOLVIE), is designed to display three-dimensional (3D) structures of molecules and support the structural analysis and research on proteins. The paper presents the features, design considerations and applications of MOLVIE, especially the new functions used to compare the structures of two molecules and view the partial fragment of a molecule. Being developed in JAVA, MOLVIE is platform-independent. Moreover, it may run on a webpage as an applet for remote users. MOLVIE is available at http://www.cs.ucsb.edu/~mli/Bioinf/software/index.html.     

面向大规模地震体的多切片实时交互绘制优化

在普通计算平台上实现大规模地震体的多切片可视化时,传统缓存调度方法由于未考虑体块与切片的空间关联,导致交互时体块命中率较低,而常用的多分辨率绘制方法也难以达到较高的绘制质量,针对这些问题,设计了一种新的高速缓存调度策略——最大距离先出（MDFO）。首先,根据交互切片的空间位置改进缓存中体块的调度优先级,保证候选体块在切片连续交互时有更高的命中率;然后,提出了两阶段切片交互绘制方法,通过使用固定分辨率体块保证交互的实时性,通过渐进细化提升最终显示质量,并进一步结合体块数据的信息熵提升用户感兴趣区域的分辨率。实验结果表明,所提方法能够有效提高体块的整体命中率,提升比例达到60%以上,同时也实现了面向应用需求的高质量图像显示,较好地解决了大规模地震体可视化在交互效率与显示质量间的矛盾。     

Pursuing interactive visualization of irregular grids

Many branches of the sciences produce sample data not arranged on rectilinear grids, and visualization of such data is generally more complex than visualizing more regular data. While isosurface algorithms such as marching cubes can be adapted with relatively little performance penalty, direct volume rendering presents more difficulties. This paper explores these issues, concentrating on algorithms for a particular kind of irregular grid known as a curvilinear grid, composed of six-sided cells that may be considered a result of the deformation of a regular rectilinear grid.     

3D stereo interactive medical visualization

Our interactive, 3D stereo display helps guide clinicians during endovascular procedures, such as intraoperative needle insertion and stent placement relative to the target organs. We describe a new method of guiding endovascular procedures using interactive 3D stereo visualizations. We use as an example the transjugular intrahepatic portosystemic shunt (TIPS) procedure. Our goal is to increase the speed and safety of endovascular procedures by providing the interventionalist with 3D information as the operation proceeds. Our goal is to provide 3D image guidance of the TIPS procedure so that the interventionalist can readily adjust the needle position and trajectory to reach the target on the first pass. We propose a 3D stereo display of the interventionalist's needle and target vessels. We also add interactivity via head tracking so that the interventionalist gains a better 3D sense of the relationship between the target vessels and the needle during needle advancement.     

GlyphLink: An interactive visualization approach for semantic graphs

Graph analysis by data visualization involves achieving a series of topology-based tasks. When the graph data belongs to a data domain that contains multiple node and link types, as in the case of semantic graphs, topology-based tasks become more challenging. To reduce visual complexity in semantic graphs, we propose an approach which is based on applying relational operations such as selecting and joining nodes of different types. We use node aggregation to reflect the relational operations to the graph. We introduce glyphs for representing aggregated nodes. Using glyphs lets us encode connectivity information of multiple nodes with a single glyph. We also use visual parameters of the glyph to encode node attributes or type specific information. Rather than doing the operations in the data abstraction layer and presenting the user with the resulting visualization, we propose an interactive approach where the user can iteratively apply the relational operations directly on the visualization. We present the efficiency of our method by the results of a usability study that includes a case study on a subset of the International Movie Database. The results of the controlled experiment in our usability study indicate a statistically significant contribution in reducing the completion time of the evaluation tasks.