Publications
Go here for a more up-to-date list of my publications.

Client-Server-Strategien zur Visualisierung komplexer Struktureigenschaften in digitalen Dokumenten der Chemie

EMVis

Authors:

K.Engel, F.Oellien, W.D.Ihlenfeldt, T.Ertl

Published on:

IT+TI 6/2000 Informationstechnik und Technische Informatik

Year:

2000

Pages:

17-23

Project Page:

N/A

Download:

[PDF]

Talk:

N/A

Abstract:
  In der Chemie wird in steigendem Ma\ss e sowohl mit hochdimensionale n Daten (drei oder mehr Dimensionen) als auch mit extrem gro\ss en Datens\"atzen (Tausende bis Millione n von Me\ss punkten und Einzeldaten) gearbeitet. Die Einbettung dreidimensionaler Visualisierungen dies er Daten in digitale Dokumente erfordert neue Strategien zur verteilten Verarbeitung und Darstellung. D er Einsatz von Client-Server-Methoden zur Minimierung der Netzbelastung bei maximaler Ausnutzung der F\"ahigkeiten der Clients und Server-Sys teme zur interaktiven Manipulation der Daten und zur Visualisierungen ist dabei unabdingbar. Anhand ein er Reihe von Client-Server-Strategien m\"ochten wir leistungsf\"ahige Verfahren zur interaktiven Bearbe itung von umfangreichen multidimensionalen Daten erl\"autern.

Interactive Volume Rendering on Standard PC Graphics Hardware Using Multi-Textures and Multi-Stage-Rasterization

EMVis

Authors:

C.Resk-Salama, K.Engel, M.Bauer, G.Greiner, T.Ertl

Published on:

In Proc. Eurographics/SIGGRAPH Workshop on
Graphics Hardware

Year:

2000

Pages:

N/A

Project Page:

N/A

Download:

[PS]

Talk:

N/A

Abstract:
  Interactive direct volume rendering has yet been restricted to high-end graphics workstations and special-purpose hardware, due to the large amount of trilinear interpolations, that are necessary to obtain high image quality. Implementations that use the 2D-texture capabilities of standard PC hardware, usually render object-aligned slices in order to substitute trilinear by bilinear interpolation. However the resulting images often contain visual artifacts caused by the lack of spatial interpolation.  In this paper we propose new rendering techniques that significantly improve both performance and image quality of the 2D-texture based approach. We will show how multi-texturing capabilities of modern consumer PC graphics boards are exploited to enable interactive high quality volume visualization on low-cost hardware. Furthermore we demonstrate how multi-stage rasterization hardware can be used to efficiently render shaded isosurfaces and to compute diffuse illumination for semi-transparent volume rendering at interactive frame rates.

Combining Local and Remote Visualization Techniques for Interactive Volume Rendering
in Medical Applications

EMVis

Authors:

K. Engel, P.Hastreiter, B. Tomandl, K.Eberhardt, T.Ertl

Published on:

IEEE Visualization

Year:

2000

Pages:

N/A

Project Page:

N/A

Download:

N/A

Talk:

N/A

Abstract:
For a comprehensive understanding of tomographic image data in medical routine, interactive and high--quality direct volume rendering is an essential prerequisite.  This is provided by visualization using 3D texture mapping which is still limited to high-end graphics hardware. In order to make it available in a clinical environment, we present a system which uniquely combines local desktop computers and remote high-end graphics hardware. In this context, we exploit the standard visualization capabilities to a maximum which are available in the clinical environment. For 3D representations of high resolution and quality we access the remote specialized hardware. Various tools for 2D and 3D visualization are provided which meet the requirements of a medical diagnosis. This is demonstrated with examples from the field of neuroradiology which show the value of our strategy in practice

A Framework for Interactive Hardware-Accelerated Remote 3D-Visualization

EMVis

Authors:

K. Engel, Ove Sommer, T.Ertl

Published on:

Data Visualization 2000, Springer Computer Science

Year:

2000

Pages:

167-177, 291

Project Page:

N/A

Download:

[PDF]

Talk:

[PPT]


Abstract:
In this paper we present a framework that provides remote control to Open Inventor or Cosmo3D based visualization applications. A visualization server distributes a visualization session to Java based clients by transmitting compressed images from the server frame buffer. Visualization parameters and GUI events from the clients are applied to the server application by sending CORBA (Common Object Request Broker Architecture) requests. The framework provides transparent access to remote visualization capabilities and allows sharing of expensive resources. Additionally the framework opens new possibilities for collaborative work and distance education. We present a teleradiology system and an automotive development application which make use of the proposed techniques.
 

Isosurface Extraction Techniques for Web-based Volume Visualization

EMVis

Authors:

K. Engel, Ruediger Westermann, T.Ertl

Published on:

IEEE Visualization

Year:

1999

Pages:

N/A

Project Page:

here

Download:

[PS]

Talk:

[PPT]

Abstract:
  The reconstruction of isosurfaces from scalar volume data has positioned itself as a fundamental visualization technique in many different applications. But the dramatically increasing size of volumetric data sets often prohibits the handling of these models on affordable low-end single processor architectures. Distributed client-server systems integrating high-bandwidth transmission channels and Web-based visualization tools are one alternative to attack this particular problem, but therefore new approaches to reduce the load of numerical processing and the number of generated primitives are required. In this paper we outline different scenarios for distributed isosurface reconstruction from large-scale volumetric data sets. We demonstrate how to directly generate stripped surface representations and we introduce adaptive and hierarchical concepts to minimize the number of vertices that have to be reconstructed, transmitted and rendered. Furthermore, we propose a novel computation scheme, which allows the user to flexibly exploit locally available resources. The proposed algorithms have been merged together in order to build a platform-independent Web-based application. Extensive use of VRML and Java OpenGL-bindings allows for the exploration of large-scale volume data quite efficiently.
   

Chemische Visualisierung und Datenintegration im Internet

EMVis

Authors:

F.Oellien, W.D. Ihlenfeldt, K.Engel, T.Ertl

Published on:

Neue Medien in Forschung und Lehre, Ein Workshop im Rahmen der 29.Jahrestagung der Gesellschaft fuer Informatik (Informatik 99)

Year:

1999

Pages:

N/A

Project Page:

N/A

Download:

N/A

Talk:

Abstract:
In den letzten Jahren hat sich das Internet innerhalb der Naturwissenschaften und hier vor allem im Bereich der Chemie als wichtiges Medium zum Austausch und zur Visualisierung von Daten etabliert. Der Vorsprung von chemischen Informationen gegenüber anderen Wissenschaften basiert dabei auf das Vorhandensein einer kleinen Anzahl von einfachen, klar definierten und nicht textorientierten Datenobjekten wie Spektren, Reaktionen, Strukturen und auch Sequenzen und den damit verbundenen Darstellungsformen. Die zur Zeit verfügbaren Web-basierten chemischen Service sind jedoch im allgemeinen nur für die Lösung von einzelnen, speziellen Fragestellungen aus diesem Kontext ausgelegt. Der chemische Alltag in Forschung und Lehre fordert jedoch die Kombination aller zugänglichen Informationen und deren Visualisierung.
Dieser Artikel beschreibt die Einbettung neuer Daten- und Visualisierungsmodule in ein bereits bestehendes, offenes, chemisches Datenmanagmentsystem (CACTVS) im Kontext des Internets. Hierbei werden anhand von verschiedenen Web-basierten Applikationen neue Wege des chemischen Datentransfers und der Visualisierung aufgezeigt
  

Remote 3D Visualization using Image-Streaming Techniques

EMVis

Authors:

K.Engel, O.Sommer, C.Ernst, T.Ertl

Published on:

International Symposium on Intelligent Multimedia and Distance Education

Year:

1999

Pages:

N/A

Project Page:

N/A

Download:

[PS]

Talk:

N/A

Abstract:
  The visualization of large scale data sets is still one of the biggest challenges in scientific visualization. In the field of web-based visualization the handling of such data sets raises new
  questions: How to distribute the visualization task onto client and server machines? How to achieve interactive refresh rates? How to reduce network load? How to adapt the visualization to the network bandwidth? How to extend single user visualization applications
  into collaborative visualization tools? In this paper we present a new approach for web-based visualization using image streaming techniques. A framework enables the remote
  control of an OpenInventor application. Images generated by a high-end visualization server are streamed through the network to visualization clients using a special video-streaming codec. The visualization on the server is controlled by CORBA (Common Object Request Broker Architecture) requests generated on the client machines. CORBA provides access to the visualization server from a large variety of client architectures - an issue which is especially important in the field of the heterogeneous World Wide Web. We  present a web-based teleradiology system which is based on the proposed techniques.
  

Texture-based Volume Visualization for Multiple Users on the World Wide Web

EMVis

Authors:

K.Engel, T.Ertl

Published on:

5th Eurographics Workshop on Virtual Environments

Year:

1999

Pages:

N/A

Project Page:

N/A

Download:

N/A

Talk:

N/A

Abstract:
We present a texture-based volume visualization tool, which permits remote access to radiological data and supports multi-user environments. The application uses JAVA and the Virtual RealityModeling Language (VRML), thus it is platform-independent and able to use fast 3D graphics acceleration hardware of client machines. The application allows the shared viewing and manipulation of three-dimensional medical volume datasets in a heterogeneous network. Volume datasets are transferred from a server to different client machines and locally visualized using a JAVA-enabled web-browser. In order to reduce network traffic, a data reduction and compression scheme is proposed. The application allows view dependent and orthogonal clipping planes, which can be moved interactively. On the client side, the users are able to join a visualization session and to get the same view onto the volume dataset by synchronizing the viewpoint and any other visualization parameter. Interesting parts of the dataset are marked for other users by placing a tag into the visualization. In order to support collaborative work users communicate with a chat applet, which we provide, or by using any existing video conferencing tool.
  

Visualizing Chemical Data on the Internet - Data-Driven and Interactive Graphics

EMVis

Authors:

W.D. Ihlenfeldt, K.Engel

Published on:

Computers and Graphics, Vol.22, No.6, Elsevier Science Ltd.

Year:

1999

Pages:

703-714

Project Page:

N/A

Download:

N/A

Talk:

N/A

Abstract:
  Chemisty faces interesting problems with regard to internet-based information visualization, especially in the context of digital library documents with multimedia components. We have developed a number of methods and applications ranging from the automatic generation of 2D structure sketches to 3D volume interactive visualization of molecular data with iso-surfaces and other 3D visualization techniques. This article gives an overview about these techniques and their potential for digital publishing and information indexing.
  

Progressive Isosurfaces on the Web

EMVis

Authors:

K.Engel, R.Grosso, T.Ertl

Published on:

IEEE Visualization - Late Breaking Hot Topics

Year:

1998

Pages:

N/A

Project Page:

here

Download:

[PS]

Talk:

N/A

Abstract:
Visualization of volume data on the WWW using the Virtual Reality Modeling Language (VRML) and the Java programming language offers new perspectives for distributed and platform independent applications. A naive approach would either transfer the volume data to the client side for local processing or it would compute the iso-surface on the server side by a marching cubes algorithm and transfer the resulting polygons to the client. In both cases the network bandwidth would be the limiting factor for large data sets. In this paper we try to overcome this restriction by using a progressive iso-surface algorithm, which allows the generation of surface hierarchies from the volume data with a level-of-detail control (LOD).  The surface hierarchy is generated on the server and the levels of resolution are transmitted to the client progressively, i.e. only the difference between two successive levels is sent across the network. In order to be platform independent on the client side, a Java applet running in a web-browser is used to reconstructs the hierarchy progressively.  The visualization of one level of resolution is done by a VRML web-browser plug-in, which allows the use of 3D graphics hardware support.  The plug-in receives the geometry from the applet using the External Authoring Interface (EAI).  In order to avoid the transmission of a large number of polygons, the user can reconstruct the surface up to a coarse level of resolution and refine it if required.  The surface hierarchy can be visualized at any level of detail up the finest level available, while the applet continuesly reconstructs the hierarchy progressively.
  

Konzeption und Implementierung von JAVA-basierten Visualisierungkomponenten fuer Embedded Systems

EMVis

Authors:

K.Engel

Published on:

Diploma Thesis

Year:

1997

Pages:

N/A

Project Page:

N/A

Download:

N/A

Talk:

N/A

Abstract: N/A

[Home] [Projects] [Publications] [Fun]