检索结果-内蒙古大学图书馆

Geometric construction of energy-minimizing Bézier curves

Science China(Information Sciences) 2011年第7期54卷 1395-1406页

作者： XU Gang 1,4,5,WANG GuoZhao 2 & CHEN WenYu 2,3 1 Institute of graphics and Image,Hangzhou Dianzi University,Hangzhou 310018,China 2 Department of Mathematics,Zhejiang University,Hangzhou 310027,China 3 School of computer Engineering,Nanyang Technological University,639798,Singapore 4 Galaad,INRIA Sophia-Antipolis,2004 Route des Lucioles,06902,France 5 State Key lab of cad & CG,Zhejiang University,Hangzhou 310027,China 1. Institute of Graphics and Image Hangzhou Dianzi University Hangzhou 310018 China4. Galaad INRIA Sophia-Antipolis 2004 Route des Lucioles 06902 Sophia Antipolis France5. State Key Lab of CAD & CG Zhejiang University Hangzhou 310027 China2. Department of Mathematics Zhejiang University Hangzhou 310027 China3. School of Computer Engineering Nanyang Technological University Singapore 639798 Singapore

Modeling energy-minimizing curves have many applications and are a basic problem of Geometric *** this paper,we propose the method for geometric design of energy-minimizing B′ezier ***,the necessary and sufficient condition on the control points for B′ezier curves to have minimal internal energy is *** on this condition,we propose the geometric constructions of three kinds of B′ezier curves with minimal internal energy including stretch energy,strain energy and jerk *** some control points,the other control points can be determined as the linear combination of the given control *** compare the three kinds of energy-minimizing B′ezier curves via curvature combs and curvature plots,and present the collinear properties of quartic energy-minimizing B′ezier *** also compare the proposed method with previous methods on efficiency and ***,several applications of the curve generation technique,such as curve interpolation with geometric constraints and modeling of circle-like curves are discussed.

关键词： curve design minimal energy geometric construction interpolation with constraints circle-like curves

来源：评论

学校读者我要写书评

暂无评论

Optimal constrained multi-degree reduction of Bézier curves with explicit expressions based on divide and conquer

引用

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 577-582页

作者： Lian ZHOU Guo-jin WANG Institute of Computer Graphics and Image Processing State Key Lab of CAD & CG Zhejiang University Hangzhou 310027 China

We decompose the problem of the optimal multi-degree reduction of Bézier curves with corners constraint into two simpler subproblems, namely making high order interpolations at the two endpoints without degree reduction, and doing optimal degree reduction without making high order interpolations at the two endpoints. Further, we convert the second subproblem into multi-degree reduction of Jacobi polynomials. Then, we can easily derive the optimal solution using orthonormality of Jacobi polynomials and the least square method of unequally accurate measurement. This method of 'divide and conquer' has several advantages including maintaining high continuity at the two endpoints of the curve, doing multi-degree reduction only once, using explicit approximation expressions, estimating error in advance, low time cost, and high precision. More importantly, it is not only deduced simply and directly, but also can be easily extended to the degree reduction of surfaces. Finally, we present two examples to demonstrate the effectiveness of our algorithm.

关键词： Bezier curves Multi-degree reduction Divide and conquer

来源：评论

学校读者我要写书评

暂无评论

A new method in highway route design:joining circular arcs by a single C-Bézier curve with shape parameter

引用

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 562-569页

作者： Hua-hui CAI Guo-jin WANG Institute of Computer Graphics and Image Processing State Key Lab of CAD & CG Zhejiang University Hangzhou 310027 China

We constructed a single C-Bezier curve with a shape parameter for G^2 joining two circular arcs. It was shown that an S-shaped transition curve, which is able to manage a broader scope about two circle radii than the Bezier curves, has no curvature extrema, while a C-shaped transition curve has a single curvature extremum. Regarding the two kinds of curves, specific algorithms were presented in detail, strict mathematical proofs were given, and the effectiveness of the method was shown by examples This method has the following three advantages：（1） the pattern is unified; （2） the parameter able to adjust the shape of the transition curve is available; （3） the transition curve is only a single segment, and the algorithm can be formulated as a low order equation to be solved for its positive root. These advantages make the method simple and easy to implement.

关键词： Transition curve C-Bezier curve Monotone curvature Shape parameter

来源：评论

学校读者我要写书评

暂无评论

Optimal approximate merging of a pair of Bézier curves with G^2-continuity

引用

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 554-561页

作者： Ping ZHU Guo-zhao WANG Institute of Computer Graphics and lmage Processing State Key Lab of CAD & CG Zhejiang University Hangzhou 310027 China

We present a novel approach for dealing with optimal approximate merging of two adjacent Bezier eurves with G^2-continuity. Instead of moving the control points, we minimize the distance between the original curves and the merged curve by taking advantage of matrix representation of Bezier curve＇s discrete structure, where the approximation error is measured by L2-norm. We use geometric information about the curves to generate the merged curve, and the approximation error is smaller. We can obtain control points of the merged curve regardless of the degrees of the two original curves. We also discuss the merged curve with point constraints. Numerical examples are provided to demonstrate the effectiveness of our algorithms.

关键词： Approximate merging Gl-continuity G^2-continuity Discrete subdivision Point constraints

来源：评论

学校读者我要写书评

暂无评论

A new method in highway route design：joining circular arcs by a single C-Bezier curve with shape paramete

引用

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷

作者： Hua-hui CAI Guo-jin WANG Institute of Computer Graphics and Image Processing State Key Lab of CAD & CG Zhejiang University

We constructed a single C-B zier curve with a shape parameter for G2 joining two circular arcs. It was shown that an S-shaped transition curve, which is able to manage a broader scope about two circle radii than the B zier curves, has no curvature extrema, while a C-shaped transition curve has a single curvature extremum. Regarding the two kinds of curves, specific algo- rithms were presented in detail, strict mathematical proofs were given, and the effectiveness of the method was shown by examples. This method has the following three advantages: (1) the pattern is unified; (2) the parameter able to adjust the shape of the tran- sition curve is available; (3) the transition curve is only a single segment, and the algorithm can be formulated as a low order equation to be solved for its positive root. These advantages make the method simple and easy to implement.

关键词： Transition curve Shape parameter C-Bezier curve Monotone curvature

来源：评论

学校读者我要写书评

暂无评论

Laplacian lines for real-time shape illustration 09

Laplacian lines for real-time shape illustration

引用

2009 ACM SIGGRAPH Symposium on Interactive 3D graphics and Games, I3D 2009

作者： Zhang, Long He, Ying Xie, Xuexiang Chen, Wei Institute of Graphics and Image Hangzhou Dianzi University China School of Computer Engineering Nanyang Technological University Singapore State Key Lab. of CAD and CG Zhejiang University China

ISBN: (纸本)9781605584294

This paper presents a novel object-space line drawing algorithm that can depict shape with view dependent feature lines in real-time. Strongly inspired by the Laplacian-of-Gaussian (LoG) edge detector in image processing, we define Laplacian Lines as the zero-crossing points of the Laplacian of the surface illumination. Compared to other view dependent features, Laplacian lines are computationally efficient because most expensive computations can be pre-processed. Thus, Laplacian lines are very promising for interactively illustrating large-scale models. Copyright © 2009 by the Association for Computing Machinery, Inc.

关键词： Image processing

来源：评论

学校读者我要写书评

暂无评论

Interactive browsing of large images on multi-projector display wall system

Interactive browsing of large images on multi-projector disp...

引用

12th International Conference on Human-computer Interaction, HCI International 2007

作者： Zhongding, Jiang Xuan, Luo Yandong, Mao Binyu, Zang Hai, Lin Hujun, Bao Computer Graphics Lab. Software School Fudan University Shanghai China State Key Lab. of CAD and CG Zhejiang University Hangzhou China

ISBN: (纸本)9783540731061

With the precision of data acquisition increases, large images that may occupy terabytes, become common in research and industry fields. Since multi-projector display wall systems can provide higher resolution, they becomes paramount to display the large images. In this paper, we present one large image viewing system designed for display wall system. Our system need not totally downloading the whole image data to each rendering node. It enables users to browse the out-of-core images in real time using data streaming techniques. In the system, the original out-of-core raw image is compressed and represented using one hierarchical structure in multi-resolution manner. We design one proxy architecture that interactive streams data from remote data server to all rendering nodes. Our system allows users to interactively pan, and zoom the large images with versatile graphical user interface. © Springer-Verlag Berlin Heidelberg 2007.

关键词： Image retrieval

来源：评论

学校读者我要写书评

暂无评论

Stretch-based tetrahedral mesh manipulation 07

Stretch-based tetrahedral mesh manipulation

引用

graphics Interface 2007

作者： Song, Wenhao Liu, Ligang Computer Graphics Department Max-Planck-Institut Informatik Saarbrücken Germany Department of Mathematics State Key Lab. of CAD and CG Zhejiang University China

ISBN: (纸本)1568813376

We present a novel least scaling distortion metric to measure the deformation distortion for tetrahedral meshes. The stretch-like metric is a combination of Jacobian matrix norm and tetrahedron volume and has the properties of good shape preservation and rotation invariance. Based on our metric, we propose a uniform non-linear optimization solution to a variety of tetrahedral mesh manipulation applications including shape deformation, interpolation, deformation transfer, and deformation learning. Our approach can produce volume preserving and flip free tetrahedral mesh results, which performs much better than the previous tetrahedral manipulation approaches. We also demonstrate an efficient and practical application using free-form deformation technique. The object is embedded in a rough control tetrahedral mesh and deformed by editing the tetrahedral mesh with various constraints. Each vertex of the object can be obtained by its barycentric coordinates according to its embedding tetrahedron of the control tetrahedral mesh.

关键词： Image analysis

来源：评论

学校读者我要写书评

暂无评论

Multi-projector display wall system for windows desktop applications

引用

Journal of Computational Information Systems 2007年第1期3卷 397-403页

作者： Jiang, Zhongding Mao, Yandong Qin, Bo Jiang, Nan Zang, Binyu Bao, Hujun Computer Graphics Laboratory Software School Fudan University Shanghai 201203 China State Key Lab. of CAD and CG Zhejiang University Hangzhou 310027 China

Large-format high-resolution display systems are increasingly adopted in virtual reality, digital museum, scientific visualization, and other application fields. Traditionally, wall size display system is driven by a cluster of PCs or special high end graphics supercomputer. With the rapid advance of PC graphics hardware, one inexpensive mainstream PC has the power to drive multiple high-resolution displays. This paper proposes one multi-projector display wall system driven by single PC. Besides graphics intensive applications, this system can transparently and efficiently display windows desktop applications without modifying the source code. It takes advantage of the bandwidth of PCI Express bus, and supports at least triple projectors, which is suitable for constructing immersive virtual reality center. Design geometric alignment and photometric correction methods are given to display the frame buffer content seamlessly on the planar display screen. Experimental results show that this system can achieve real time refresh rates. It does little side effect on the performance of common non-graphics windows desktop applications.

关键词： Display devices

来源：评论

学校读者我要写书评

暂无评论

Technologies for E-Learning and Digital Entertainment 2006

引用

丛书名： Lecture Notes in computer Science

2006年

作者： Zhigeng Pan Ruth Aylett Holger Diener Xiaogang Jin Stefan Göbel Li Li

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：