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Rhinosurgical therapy planning via endonasal airflow simulation†

computer Aided Surgery 2000年第3期5卷

作者： Uli Bockholt Dipl.-Math. Gunter Mlynski M.D. Wolfgang Müller Dipl.-Inf. Gerrit Voss Dipl.-Inf. Darmstadt University of Technology Interactive Graphics Systems Group (GRIS) Darmstadt ENT-Clinic Ernst-Moritz-Arndt University Greifswald Greifswald and Fraunhofer Institute for Computer Graphics (Fraunhofer-IGD) Department of Visualization & Virtual Reality Darmstadt Germany

Nowadays, Computational Fluid Dynamics (CFD) methods play an important part in the production process of the automotive industry. Progress in recent years has made possible highly sophisticated airflow-simulation models that are used in engineering for optimization and verification of aerodynamics. The key purpose of the Simulation Tool for Airflow in the human Nose (STAN), developed at the Darmstadt University of Technology in cooperation with the University Hospital in Greifswald, is to use these techniques to support the rhinosurgeon in diagnosis and planning of therapy (Frühauf T, Mlynski G. Simulation and visualization of the air flow in the human nose. Proceedings of the First World Congress on Computational Medicine, Austin, Texas, 1994). A system has been developed that realizes a three-dimensional (3D) reconstruction of the endonasal cavities based on computer tomography (CT) scans. This semiautomatic reconstruction method requires minimal manual intervention. The surface model is used to create an unstructured 3D volume mesh suitable for finite volume simulations. In this way, an individual simulation based on patient-specific data can be realized. At the University Hospital in Greifswald, experimental investigations and measurements are made in nasal models to verify the simulation result. The goal of this project is to investigate individual nasal complaints and to detect respiratory disorders. The surgeon should be able to simulate the disordered respiration before performing a surgical procedure, and thereby increase the effectiveness of surgical planning. Comp Aid Surg 5:175–179 (2000). © 2000 Wiley-Liss, Inc.

关键词： biomechanical simulation computer-aided diagnosis computational biofluids rhinosurgery

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Skin: A constructive approach to modeling free-form shapes 99

Skin: A constructive approach to modeling free-form shapes

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26th Annual Conference on computer graphics and Interactive Techniques, SIGGRAPH 1999

作者： Markosian, Lee Cohen, Jonathan M. Crulli, Thomas Hughes, John Brown University Site of the NSF Technology Center for Computer Graphics and Scientific Visualization Box 1910 ProvidenceRI02912 United States

ISBN: (纸本)0201485605

We present a new particle-based surface representation with which a user can interactively sculpt free-form surfaces. The particles maintain mesh connectivity and operate under rules that lead them to form triangulations with properties that make them suitable for use in subdivision. A user interactively guides the particles, which we call skin, to grow over a given collection of polyhedral elements (or skeletons), yielding a smooth surface (through subdivision) that approximates the underlying skeletal shapes. Skin resembles blobby modeling in the constructive approach to modeling it supports, but allows a richer vocabulary of skeleton shapes, supports sharp creases where desired, and provides a convenient mechanism for adding multiresolution surface detail. Copyright ACM 1999.

关键词： Musculoskeletal system

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Granularity in the design of interactive illustrations 13

Granularity in the design of interactive illustrations

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13th SIGCSE Technical Symposium on computer Science Education, SIGCSE 1999

作者： Gould, Daniel L. Simpson, Rosemary M. Van Dam, Andries Brown University NSF Science and Technology Center Computer Graphics and Scientific Visualization Box 1910 ProvidenceRI02912 United States

ISBN: (纸本)9781581130850

We describe some issues in designing and building educational Java applets for an introductory computer graphics course. The design problem involves balancing educational goals of building intuition about fundamental concepts in a domain against heterogeneity both in subject material and in student backgrounds. We present our design approach for resolving these forces - fine-grained units addressing small concepts - and discuss its effects on other areas including hypertext structure, interface design, and software engineering. © 1999 ACM.

关键词： User interfaces

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Virtual cutting of anatomical structures

Virtual cutting of anatomical structures

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7th Conference on Medicine Meets Virtual Reality, MMVR 1999

作者： Voß, Gerrit Hahn, James K. Müller, Wolfgang Lindeman, Rob Fraunhofer Institute for Computer Graphics Dep. Visualization and Virtual Reality Rundeturmstr. 6 64283 Darmstadt Germany Laboratory for Advanced Computer Applications in Medicine Institute for Computer Graphics George Washington University Washington DC 20052 United States

ISBN: (纸本)9051994451

In the context of medicine cutting is one of the most important operations. Many surgical tasks start with an incision, allowing the surgeon to access the region of interest, using either conventional or minimal invasive surgery techniques. The work presented herein should be seen in the context of surgical training and preoperative planning using computer assisted medical simulation systems. The main result of this work is the proposed cutting algorithm based on predefined templates. To integrate this approach in the existing surgical training simulator and to handle additional tasks like soft tissue deformation, needed by the medical environment, a generic simulation framework was developed. This framework is able to utilize given multiprocessor- and network-environments to achieve the desired realtime interactivity.

关键词： Image segmentation

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A multimodal interface framework for using hand gestures and speech in virtual environment applications 3rd

A multimodal interface framework for using hand gestures and...

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3rd International Gesture Workshop on Gesture-Based Communication in Human-computer Interaction, GW 1999

作者： Laviola, Joseph J. Brown University Site of the NSF Science and Technology Center Computer Graphics and Scientific Visualization PO Box 1910 ProvidenceRI02912 United States

ISBN: (纸本)3540669353

Recent approaches to providing users with a more natural method of interacting with virtual environment applications have shown that more than one mode of input can be both beneficial and intuitive as a communication medium between humans and computer applications. Hand gestures and speech appear to be two of the most logical since users will typically be in environments that will have them immersed in a virtual world with limited access to traditional input devices such as the keyboard or the mouse. In this paper, we describe an ongoing research project to develop multimodal interfaces that incorporate 3D hand gestures and speech in virtual environments. © Springer-Verlag Berlin Heidelberg 1999.

关键词： Virtual reality

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Volume visualization on sparse grids Texture hardware based volume rendering on compressed data sets

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Computing and visualization in Science 1999年第1期2卷 47-59页

作者： Teitzel, Christian Hopf, Matthias Grosso, Roberto Ertl, Thomas Computer Graphics Group University of Erlangen Am Weichselgarten 9 D-91058 Erlangen Germany Visualization and Interactive Systems Group IfI University of Stuttgart Breitwiesenstr. 20-22 D-70565 Stuttgart Germany Siemens AG Werner-von-Siemens-Str. 60 D-91052 Erlangen Germany

Volume rendering is an important technique of displaying volumetric three-dimensional scalar data sets resulting from measurement or simulation. Additionally, sparse grids are of increasing interest in numerical simulations. Based upon hierarchical tensor product bases, the sparse grid approach is a very efficient one improving the ratio of invested storage and computing time to the achieved accuracy for many problems in the area of numerical solution of partial differential equations, for instance in numerical fluid mechanics. The volume visualization algorithms that are available so far cannot cope with sparse grids. We present an approach that directly works on these grids. As a second aspect in this paper, we suggest to use sparse grids as a data compression method in order to visualize huge data sets even on workstations with low main memory. Since the size of data sets used in numerical simulations is still growing, this feature makes it possible that workstations can continue to handle these data sets. In addition to the standard sparse grid interpolation algorithm and the so-called combination technique, we have developed a new sparse grid interpolation method, which harnesses the texture-mapping hardware of graphics workstations for acceleration purposes. Therefore, hardware based volume rendering becomes possible on compressed data sets at interactive frame rates. This is not possible if other compression methods like wavelet or fractal compression are used. © 1999 Springer-Verlag.

关键词： Volume rendering

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An interface for sketching 3D curves 99

An interface for sketching 3D curves

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Proceedings of the 1999 symposium on Interactive 3D graphics

作者： Jonathan M. Cohen Lee Markosian Robert C. Zeleznik John F. Hughes Ronen Barzel Brown University Site of the NSF Science and Technology Center for Computer Graphics and Scientific Visualization Providence RI PIXAR

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Interactive visualization of fluid dynamics simulations in locally refined cartesian grids

Interactive visualization of fluid dynamics simulations in l...

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IEEE Conference on visualization

作者： M. Schulz F. Reck W. Bertelheimer T. Ertl Visualization and Interactive Systems Group University of Stuttgart Germany BMW AG Munich Germany IMMD IX Computer Graphics Group University of Erlangen Germany Lehrstuhl für Graphische Datenverarbeitung IMMD IX Erlangen Germany

ISBN: (纸本)078035897X

The work presents interactive flow visualization techniques specifically adapted for PowerFLOW/sup TM/, a lattice based CFD code from the EXA corporation. Their Digital Physics/sup TM/ fluid simulation technique is performed on a hierarchy of locally refined cartesian grids with a fine voxel resolution in areas of interesting flow features. Among other applications, the PowerFLOW solver is used for aerodynamic simulations in car body development where the advantages of automatic grid generation from CAD models is of great interest. In a joint project with BMW and EXA, we are developing a visualization tool which incorporates virtual reality techniques for the interactive exploration of the large scalar and vector data sets. We describe the specific data structures and interpolation techniques and we report on fast particle tracing, taking into account collisions with the car body geometry. An OpenGL Optimizer based implementation allows for the inspection of the flow with particle probes and slice probes at interactive frame rates.

关键词： Fluid dynamics Probes Lattices Computational fluid dynamics Physics Aerodynamics Mesh generation Power generation Data visualization Virtual reality

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Real-time simulation of tissue deformation for the nasal endoscopy simulator (NES)

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computer Aided Surgery 1999年第5期4卷

作者： Uli Bockholt Dipl.-Math. Wolfgang Müller Dipl.-Inf. Gerrit Voss Dipl.-Inf. Ulrich Ecke M.D. Ludger Klimek M.D. Interactive Graphics Systems Group (GRIS) Darmstadt University of Technology Darmstadt Mainz University Hospital Mainz Germany Department of Visualization and Virtual Reality Fraunhofer Institute for Computer Graphics (Fraunhofer-IGD) Darmstadt Mainz University Hospital Mainz Germany Department of Otolaryngology Head and Neck Surgery Mainz University Hospital Mainz Germany

Endonasal sinus surgery requires a great amount of training before it can be adequately performed. The complicated anatomy involved, the proximity of relevant structures, and the variability of the anatomy due to inborn or iatrogenic variations make several complications possible. Today, cadaver dissections are the “gold standard” for surgical training. To overcome the drawbacks of traditional training methods, the Fraunhofer Institute for computer graphics is currently developing a highly interactive medical simulation system for nasal endoscopy and endonasal sinus surgery, in cooperation with the Mainz University Hospital. For the simulation of a rhinoscopic procedure, not only are the realization of the 3D interaction and the geometric representation of the anatomical structures necessary, but also a real-time simulation of the deformation behavior constrained by the instrument collisions. The challenge is to close the gap between a maximal degree of realism and the required real-time conditions. Comp Aid Surg 4:281–285 (1999). © 1999 Wiley-Liss, Inc.

关键词： surgical simulation skill training virtual reality soft tissue deformation rhinoscopic education

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The office of the future: A unified approach to image-based modeling and spatially immersive displays 98

The office of the future: A unified approach to image-based ...

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25th Annual Conference on computer graphics and Interactive Techniques, SIGGRAPH 1998

作者： Raskar, Ramesh Welch, Greg Cutts, Matt Lake, Adam Stesin, Lev Fuchs, Henry University of North Carolina at Chapel Hill NSF Science and Technology Center for Computer Graphics and Scientific Visualization CB 3175 Sitterson Hall Chapel Hill NC 27599-3175 United States

ISBN: (纸本)0897919998

We introduce ideas, proposed technologies, and initial results for an office of the future that is based on a unified application of computer vision and computer graphics in a system that combines and builds upon the notions of the CAVE™, tiled display systems, and image-based modeling. The basic idea is to use real-time computer vision techniques to dynamically extract per-pixel depth and reflectance information for the visible surfaces in the office including walls, furniture, objects, and people, and then to either project images on the surfaces, render images of the surfaces, or interpret changes in the surfaces. In the first case, one could designate every-day (potentially irregular) real surfaces in the office to be used as spatially immersive display surfaces, and then project high-resolution graphics and text onto those surfaces. In the second case, one could transmit the dynamic image-based models over a network for display at a remote site. Finally, one could interpret dynamic changes in the surfaces for the purposes of tracking, interaction, or augmented reality applications. To accomplish the simultaneous capture and display we envision an office of the future where the ceiling lights are replaced by computer controlled cameras and "smart" projectors that are used to capture dynamic image-based models with imperceptible structured light techniques, and to display high-resolution images on designated display surfaces. By doing both simultaneously on the designated display surfaces, one can dynamically adjust or autocalibrate for geometric, intensity, and resolution variations resulting from irregular or changing display surfaces, or overlapped projector images. Our current approach to dynamic image-based modeling is to use an optimized structured light scheme that can capture per-pixel depth and reflectance at interactive rates. Our system implementation is not yet imperceptible, but we can demonstrate the approach in the laboratory. Our approach to rende

关键词： Reflection

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