检索结果-内蒙古大学图书馆

Geometric Modeling and Processing

作者： R. Schneider L. Kobbelt Computer Graphics Group Max Planck Institute of Computer Science Saarbrucken Germany

We present a new algorithm to create fair discrete surfaces satisfying prescribed G/sup 1/ boundary constraints. All surfaces are built by discretizing a partial differential equation based on pure geometric intrinsics. The construction scheme is designed to produce meshes that are partitioned into regular domains. Using this knowledge in advance we can develop a fast iterative algorithm resulting in surfaces of high aesthetic quality that have no local mean curvature extrema in the interior.

关键词： Boundary conditions Artificial intelligence Calculus Differential equations Iterative algorithms Linear systems Partial differential equations Laplace equations Finite difference methods Finite element methods

来源：评论

学校读者我要写书评

暂无评论

A new virtual planning system for neuroendoscopic interventions

引用

Klinische Neuroradiologie 2000年第4期10卷 153-160页

作者： Freudenstein, Dirk Bartz, Dirk Merkle, Martin Ernemann, Ulrike Skalej, Martin Duffner, Frank Department of Neurosurgery University Hospital Eberhard-Karls University Tübingen Germany Wilhelm Schickard Institute for Computer Science Computer Graphics Lab Eberhard-Karls University Tübingen Germany Department of Neuroradiology University Hospital Eberhard-Karls University Tübingen Germany

The demand on virtual planning systems is increasing, in particular for technical pretentious surgical interventions such as intracranial endoscopy. In this paper, a new virtual system for neuroendoscopy is presented. The main purpose of this system is to provide support for the planning and training of neuroendoscopic interventions. The software is applied for virtual endoscopic visualization of three-dimensional magnetic resonance data sets, using a clinical magnetic resonance scanner. Rendering is performed on a Hewlett-Packard unix workstation. Virtual endoscopy provides a three-dimensional view of the cerebral ventricles with good visualization of anatomic details. The rendering system used allows the generation of fly-through sequences through the entire ventricular system in real-time. Navigation is controlled by mouse movements. The visualization of the computer generated intraventricular spaces is adapted to the characteristics of the optical endoscope. The presented virtual neuroendoscopy system is a promising tool for planning and training of neuroendoscopic procedures. It provides the ability to simulate these procedures based on the patient's individual anatomy, prior to surgery.

关键词： Neuroendoscopy Neuronavigation Neurosurgery Virtual endoscopy Virtual environments Virtual medicine

来源：评论

学校读者我要写书评

暂无评论

Local and global geometric methods for analysis, interrogation, reconstruction, modification and design of shape

Local and global geometric methods for analysis, interrogati...

引用

computer graphics International

作者： F.-E. Wolter K.-I. Friese Welfen Laboratory Division of Computer Graphics and Geometric Modeling Institute of Computer Science University of Hannover Hanover Germany

Gives an overview of some recent methods useful for local and global shape analysis and for the design of solids. These methods include, as new tools for global and local shape analysis, the spectra of the Laplace and Laplace-Beltrami operators and the concept of stable umbilical points, i.e. stable singularities of the "principal curvature line" wire-frame model of the solid's boundary surface. Most of the material in this paper deals with the medial axis transform as a tool for shape interrogation, reconstruction, modification and design. We show that it appears to be possible to construct an intuitive user interface that allows one to mould shapes by employing the medial axis transform. We also explain that the medial axis and Voronoi diagram can also be defined and computed on free surfaces in a setting where the geodesic distance between two points p and q on a surface S is defined by the shortest surface path on S joining the two points p, q. This leads to the natural and computable generalized concepts of the geodesic medial axis and geodesic Voronoi diagram on free-form surfaces. Both can be computed with a reasonable speed and with high accuracy (of about 12 digits when double floating-point arithmetic is used for the computations).

关键词： Shape Electrical capacitance tomography Solid modeling Geophysics computing Spline Surface topography Surface reconstruction Laboratories computer graphics computer science

来源：评论

学校读者我要写书评

暂无评论

VisOK: a flexible visualization system for distributed Java object application

VisOK: a flexible visualization system for distributed Java ...

引用

International Symposium on Parallel and Distributed Processing (IPDPS)

作者： Dong-Woo Lee R.S. Ramakrishna Parallel Computing & Computer Graphics Laboratory Gwangju Institute of Science and Technology Kwangju South Korea

Distributed object systems are known to be very complex. Consequently it is very difficult, if not impossible, to see the overall relationship among participating objects in the system. That complicates the issues connected with performance tuning and maintenance. An economical way to visualize the system is clearly needed. In this paper, we propose a tracing facility for Java-based distributed object system, especially Java RMI (Remote Method Invocation). Our visualization system VisOK (Visual Object-Kit) uses two-phase hybrid post-mortem/on-the-fly technique. The fundamental tracing part has a flexible and dynamic mechanism. The main idea behind the tracing technique is the plug-in sensor model (PSM). There is a close relationship between tracing part and the visualization part. For effective visualization of a working system, the causality of events has to be preserved VisOK supports global event ordering. And for collecting and assembling local states of objects, we propose a distributed snapshot algorithm.

关键词： Visualization Java Electrical capacitance tomography Hip Debugging Data mining Instruments Application software Parallel processing computer graphics

来源：评论

学校读者我要写书评

暂无评论

A novel bidirectional framework for control and refinement of area based correlation techniques

A novel bidirectional framework for control and refinement o...

引用

15th International Conference on Pattern Recognition, ICPR 2000

作者： Werth, Peter Scherer, Stefan Erich-Schmid-Institute for Materials Science Austrian Academy of Sciences Jahnstr. 12 LeobenA-8700 Austria Computer Graphics and Vision Graz University of Technology Inffeldgasse 16/2 GrazA-8010 Austria

ISBN: (纸本)0769507506

A key issue in performing stereo reconstruction is to find stereo correspondences. For this purpose a novel unified framework for arbitrary area based correlation methods is presented. The commonly neglected problem of ambiguities is addressed and a solution based on relaxation of match candidates is introduced. The method comes with the major benefits of a reverse matching step at almost no extra computational cost. The results of one match direction is used to select match candidates. Then these candidates are correlated backward with a different method. The proposed framework does not require any initial estimations. Experiments are performed on ground truth under varying geometric and varying noise conditions. Finally the method is compared to a number of well known techniques. © 2000 IEEE.

关键词： Correlation methods

来源：评论

学校读者我要写书评

暂无评论

Computing the penetration depth of two convex polytopes in 3d 7th

引用

7th Scandinavian Workshop on Algorithm Theory, SWAT 2000

作者： Agarwal, Pankaj K. Guibas, Leonidas J. Har-Peled, Sariel Rabinovitch, Alexander Sharir, Micha Center for Geometric Computing Department of Computer Science Duke University Box 90129 DurhamNC27708-0129 United States Computer Graphics Laboratory Computer Science Department Stanford University StanfordCA94305 United States Synopsys Inc 154 Crane Meadow Rd Suite 300 MarlboroMA01752 United States School of Mathematical Sciences Tel Aviv University Tel Aviv69978 Israel Courant Institute of Mathematical Sciences New York University NY10012 United States

ISBN: (纸本)3540676902

Let A and B be two convex polytopes in R3 with m and n facets, respectively. The penetration depth of A and B, denoted as π(A, B), is the minimum distance by which A has to be translated so that A and B do not intersect. We present a randomized algorithm that computes π(A,B) in O(m3/4+ɛn3/4+ɛ + m1+ɛ + n1+ɛ) expected time, for any constant ɛ > 0. It also computes a vector t such that ||t|| = π(A,B) and int(A + t) ⊓ B = θ. We show that if the Minkowski sum B ⊗ (—A) has K facets, then the expected running time of our algorithm is O (K1/2+ɛm1/4n1/4 + m1+ɛ + n1+ɛ), for any ɛ > 0. We also present an approximation algorithm for computing π(A,B). For any δ > 0, we can compute, in time O(m + n + (log2(m + n))/δ), a vector t such that ||t|| 2 n)/δ), which is simpler and slightly faster than the recent algorithm by Chan. © Springer-Verlag Berlin Heidelberg 2000.

关键词： Approximation algorithms

来源：评论

学校读者我要写书评

暂无评论

SQUEEZE: fast and progressive decompression of triangle meshes

SQUEEZE: fast and progressive decompression of triangle mesh...

引用

computer graphics International

作者： R. Pajarola J. Rossignac Information & Computer Science University of California Irvine USA Graphics Visualization & Usability Center College of Computing Georgia Institute of Technology USA

An ideal triangle mesh compression technology would simultaneously support the following objectives: (1) progressive refinements of the received mesh during decompression, (2) nearly optimal compression ratios for both geometry and connectivity, and (3) in-line, real-time decompression algorithms for hardware or software implementations. Because these three objectives impose contradictory constraints, previously reported efforts have focused primarily on one (sometimes two) of these objectives. The SQUEEZE technique introduced in this paper addresses all three constraints simultaneously, and attempts to provide the best possible compromise. For a mesh of T triangles, SQUEEZE compresses the connectivity to 3.7T bits, which is competitive with the best progressive compression techniques reported so far. The geometric prediction error encoding technique introduced in this paper leads to a geometry compression that is improved by 20% over that of previous schemes. Our initial implementation on a 300-MHz CPU achieved a decompression rate of up to 46,000 triangles per second. SQUEEZE downloads a model through a number of successive refinement stages, providing the benefit of progressivity.

关键词： Hardware Encoding Bandwidth Geometry Image coding Shape Solid modeling computer science computer graphics Visualization

来源：评论

学校读者我要写书评

暂无评论

AlVis - An aluminium-foam visualization and investigation tool

AlVis - An aluminium-foam visualization and investigation to...

引用

2nd Joint Eurographics - IEEE TCVG Symposium on Visualization, VisSym 2000

作者： König, Andreas H. Doleisch, Helmut Kottar, Andreas Kriszt, Brigitte Gröller, Eduard Institute of Computer Graphics Vienna University of Technology Karlsplatz 13 ViennaA-1040 Austria Institute of Experimental Physics Vienna University of Technology Karlsplatz 13 ViennaA-1040 Austria Department of Material Science and Testing Vienna University of Technology Karlsplatz 13 ViennaA-1040 Austria

ISBN: (纸本)3211835156

In recent years there has been an increased interest in metal foams in the field of material science. The stress absorbing potential is one of the most interesting properties for the application of aluminium foam (e.g. car manufacturing). Material scientists need to investigate the structure of metal foams in order to optimize their deformation behavior. An interactive tool for the investigation is presented in this work. Real-time surface rendering, automatic parameter determination, and display of local and global foam properties enable the user to understand the complex structure of the metal foam. © 2000 Eurographics Association. All rights reserved.

关键词： Aluminum

来源：评论

学校读者我要写书评

暂无评论

A novel bidirectional framework for control and refinement of area based correlation techniques

A novel bidirectional framework for control and refinement o...

引用

International Conference on Pattern Recognition

作者： P. Werth S. Scherer Computer Graphics and Vision Graz University of Technology Graz Austria Erich-Schmid-Institute for Materials Science Austrian Academy of Sciences Leoben Austria

ISBN: (纸本)0769507506

A key issue in performing stereo reconstruction is to find stereo correspondences. For this purpose a novel unified framework for arbitrary area based correlation methods is presented. The commonly neglected problem of ambiguities is addressed and a solution based on relaxation of match candidates is introduced. The method comes with the major benefits of a reverse matching step at almost no extra computational cost. The results of one match direction is used to select match candidates. Then these candidates are correlated backward with a different method. The proposed framework does not require any initial estimations. Experiments are performed on ground truth under varying geometric and varying noise conditions. Finally, the method is compared to a number of well known techniques.

关键词： Stereo image processing Correlation Image matching Noise robustness Materials science and technology Image reconstruction Computational efficiency Stereo vision computer graphics Computational complexity

来源：评论

学校读者我要写书评

暂无评论

Fast and stable animation of cloth with an approximated implicit method

Fast and stable animation of cloth with an approximated impl...

引用

computer graphics International

作者： Young-Min Kang Jeong-Hyeon Choi Hwan-Gue Cho Chan-Jong Park Graphics Application Lab Department of Computer Science Pusan National University South Korea Virtual Reality Center Electronics and Telecommunication Research Institute

Realistic animation of soft objects such as cloth is essential for plausible character animation. Many techniques have been proposed for the simulation of soft objects, and most of them are based on numerical integration. Among the techniques, the implicit integration method is the most likely technique for real time environments, since it allows large time steps for cloth simulation by ensuring the stability of systems. However the most critical flaw of the implicit method is that it involves a large linear system. The paper presents a fast animation technique for animating soft objects based on a mass-spring model with an approximated implicit method which does not involve linear system solving. The proposed technique stably updates the state of n mass-points in O(n) time when the number of total springs are O(n). Because the mass-spring model shows a superelastic effect, the excessively deformed springs (i.e., super-elongated springs) should be adjusted for reality. The paper presents an efficient inverse dynamics process to adjust the super-elongated springs.

关键词： Animation Springs Computational modeling Linear systems Stability Deformable models Electrical capacitance tomography Image generation computer graphics Application software

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：