检索结果-内蒙古大学图书馆

7th pacific conference on computer graphics and applications, pacific graphics 1999

作者： Rodler, Flemming Friche BRICS Department of Computer Science University of Aarhus Denmark

ISBN: (纸本)0769502938

In this paper we propose a wavelet based method for compressing volumetric data with little loss in quality allowing fast random access to individual voxels within the volume. Such a method is important since storing and visualising very large volumes impose heavy demands on internal memory and external storage facilities, a problem not likely to become less in the future, making it accessible only to users with huge and expensive computers. Experimental results on the CT dataset of the Visible Human have shown that our method provides very high compression rates with fairly fast random access. © 1999 IEEE.

关键词： Wavelet transforms

来源：评论

学校读者我要写书评

暂无评论

Simulating the aurora borealis 8

Simulating the aurora borealis

引用

8th pacific conference on computer graphics and applications

作者： Baranoski, GVG Rokne, JG Shirley, P Trondsen, T Bastos, R Univ Utah Salt Lake City UT 84112 USA

ISBN: (纸本)0769508685

We present an algorithm to stimulate the aurora borealis, commonly known as the 'northern lights", a natural phenomenon of great visual beauty and considerable scientific interest. The algorithm is based on the current understanding of the physical origin of the aurora. This natural display is mainly caused by high-energy electrons originating in the Sun and entering the Earth's atmosphere in narrow regions centered on the magnetic poles. These electrons collide with atmospheric atoms which are excited to higher energy levels. The excited atoms emit rapidly varying visible light bl a curtain-like volume as they return to In,ver energy levels thereby creating the aurora. By simulating these light emissions along with the spatial and temporal distribution of the entering electrons, we are able to render the major visual aspects of auroral displays. This approach also allows the representation of time-dependent features that characterize the dynamic nature of the aurorae. The applicability of this auroral model for artistic and research purposes is illustrated through comparisons of synthetic images with photographs of real auroral displays.

关键词： Acceleration Atmosphere Atmospheric modeling Computational modeling computer science computer simulation Displays Electrons Physics Sun

来源：评论

学校读者我要写书评

暂无评论

Eigenanalysis and continuity of non-uniform Doo-Sabin surfaces 7

Eigenanalysis and continuity of non-uniform Doo-Sabin surfac...

引用

7th pacific conference on computer graphics and applications, pacific graphics 1999

作者： Qin, Kaihuai Wang, Huawei Dept. of Computer Science and Technology Tsinghua University Beijing100084 China

ISBN: (纸本)0769502938

In computer graphics and computer-aided geometric design, more and more subdivision schemes are being extensively used for free-form surfaces of arbitrary topology. The convergence and continuity analyses of uniform subdivision surfaces have been performed very well, but it is very difficult to prove the convergence and the continuity properties of non-uniform recursive subdivision surfaces (NURSSes, for short) because the subdivision matrix varies at each iteration step. This restricts widespread use of NURSSes, although NURSSes have a lot of advantages over uniform subdivision surfaces. In this paper, the concept of equivalent knot spacing is presented. A new technique for eigenanalysis, convergence and continuity analyses of non-uniform Doo-Sabin surfaces is proposed. Also, an interesting and important fact is found that the subdivision process of nonuniform Doo-Sabin surfaces may diverge sometime. © 1999 IEEE.

关键词： computer graphics

来源：评论

学校读者我要写书评

暂无评论

Data-Driven Sparse Priors of 3D Shapes

引用

computer graphics FORUM 2017年第7期36卷 63-72页

作者： Remil, O. Xie, Q. Xie, X. Xu, K. Wang, J. Nanjing Univ Aeronaut & Astronaut Nanjing Jiangsu Peoples R China Ecole Mil Polytech Bordj El Bahri Algeria Natl Univ Def Technol Changsha Hunan Peoples R China Chuzhou Univ Chuzhou Anhui Peoples R China

We present a sparse optimization framework for extracting sparse shape priors from a collection of 3D models. Shape priors are defined as point-set neighborhoods sampled from shape surfaces which convey important information encompassing normals and local shape characterization. A 3D shape model can be considered to be formed with a set of 3D local shape priors, while most of them are likely to have similar geometry. Our key observation is that the local priors extracted from a family of 3D shapes lie in a very low-dimensional manifold. Consequently, a compact and informative subset of priors can be learned to efficiently encode all shapes of the same family. A comprehensive library of local shape priors is first built with the given collection of 3D models of the same family. We then formulate a global, sparse optimization problem which enforces selecting representative priors while minimizing the reconstruction error. To solve the optimization problem, we design an efficient solver based on the Augmented Lagrangian Multipliers method (ALM). Extensive experiments exhibit the power of our data-driven sparse priors in elegantly solving several high-level shape analysis applications and geometry processing tasks, such as shape retrieval, style analysis and symmetry detection.

关键词： Categories and Subject Descriptors (according to ACM CCS) I.3.5 [computer graphics]: Computational Geometry and Object Modeling—Geometric algorithms languages and systems

来源：评论

学校读者我要写书评

暂无评论

A physics-based framework for subdivision surface design with automatic rules control 10

A physics-based framework for subdivision surface design wit...

引用

10th pacific conference on computer graphics and applications

作者： Xie, H Qin, H SUNY Stony Brook Dept Comp Sci Stony Brook NY 11794 USA

ISBN: (纸本)0769517846;0769517854

The recent non-uniform subdivision approach extends traditional uniform subdivision schemes with variable rules, offering additional shape parameters (such as knot spacings) for feature control. Despite its flexibility, shape modification based on non-uniform subdivision usually requires designers to interactively adjust a large number of degrees of freedom (DOFs) to achieve the desired shapes, which can often be laborious. This paper extends the principle of variational subdivision and integrates the non-unifonn subdivision schemes with powerful physics-based shape sculpting techniques, providing a universal method for arbitrary subdivision schemes with adjustable rules. The subdivision control points and knot spacings evolve in response to the shape deformation resulting from the numerical integration of Lagrangian dynamics equation or the optimization of shape energy functional. Thus, our system allows users to manipulate the desired shape in a direct and intuitive fashion. In addition, we propose a novel and efficient discrete functional evaluation method for polygonal meshes or point cloud of arbitrary topology based on implicit functions, in which no parameterization is needed. Finally, we develop a simple prototype sculpting system demonstrating many advantages of our novel physics-based, non-uniform subdivision modeling system.

关键词： computer graphics CAD physics-based modeling subdivision

来源：评论

学校读者我要写书评

暂无评论

Lighting interpolation by shadow morphing using intrinsic Lumigraphs 10

Lighting interpolation by shadow morphing using intrinsic Lu...

引用

10th pacific conference on computer graphics and applications

作者： Matsushita, Y Kang, SB Lin, S Shum, HY Tong, X Univ Tokyo Inst Ind Sci Meguro Ku Tokyo 1538505 Japan

ISBN: (纸本)0769517846;0769517854

Densely-sampled image representations such as the light field or Lumigraph have been effective in enabling photorealistic image synthesis. Unfortunately, lighting interpolation with such representations has not been shown to be possible without the use of accurate 3D geometry and surface reflectance properties. In this paper we propose an approach to image-based lighting interpolation that is based on estimates of geometry and shading from relatively few images. We decompose captured light fields at different lighting conditions into intrinsic images (reflectance and illumination images), and estimate view-dependent scene geometries using multi-view stereo. We call the resulting representation an Intrinsic Lumigraph. In the same way that the Lumigraph uses geometry to permit more accurate view interpolation, the Intrinsic Lumigraph uses both geometry and intrinsic images to allow high-quality interpolation at different views and lighting conditions. Joint use of geometry and intrinsic images is effective in the computation of shadow masks for shadow prediction at new lighting conditions. We illustrate our approach with images of real scenes.

关键词： Asia Cameras Geometry Image representation Interpolation Layout Lighting Rendering (computer graphics) Shape Solid modeling

来源：评论

学校读者我要写书评

暂无评论

Real-time virtual humans

Real-time virtual humans

引用

5th pacific conference on computer graphics and applications (pacific graphics 97)

作者： Badler, NI Univ of Pennsylvania Philadelphia United States

ISBN: (纸本)0818680288

The last few years have seen great maturation in the computation speed and control methods needed to portray 3D virtual humans suitable for real interactive applications. We first describe the state of the art, then focus on the particular approach taken at the University of Pennsylvania with the Jack system. Various aspects of real-time virtual humans are considered, such as appearance and motion, interactive control, autonomous action, gesture, attention, locomotion, and multiple individuals. The underlying architecture consists of a sense-control-act structure that permits reactive behaviors to be locally adaptive to the environment, and a PaT-Net parallel finite-state machine controller that can be used to drive virtual humans through complex tasks. We then argue for a deep connection between language and animation and describe current efforts in linking them through Two systems: the Jack Presenter and the JackMOO extension to lambdaMOO. Finally, we outline a Parameterized Action Representation for mediating between language instructions and animated actions.

关键词： virtual humans human modeling computer animation virtual reality autonomous agents language and action computer graphics

来源：评论

学校读者我要写书评

暂无评论

VISBONE: 3D visualization of bone mineral density 7

VISBONE: 3D visualization of bone mineral density

引用

7th pacific conference on computer graphics and applications, pacific graphics 1999

作者： Choi, Yi-King Leong, J.C.Y. Lu, W.W. Wang, Weuping Department of Computer Science and Information Systems University of Hong Kong Pokfulam Road Hong Kong Department of Orthopaedic Surgery University of Hong Kong Pokfulam Road Hong Kong

ISBN: (纸本)0769502938

Volume visualization is an essential part of many computer-assisted medical applications. While general-purpose commercial visualization software can provide common functions for visualizing three-dimensional (3D) medical data, there are many occasions where specific requirements cannot be fulfilled by such software. In orthopaedic surgery involving screw insertion, surgeons must consider not only the surface topology but also the bone mineral density (BMD) distribution to ensure a high success rate of the operation. In this paper we present a new system, called VISBONE, for visualizing the 3D BMD distribution within a bone. Design issues and specific considerations required by this application are discussed. © 1999 IEEE.

关键词： Medical applications

来源：评论

学校读者我要写书评

暂无评论

General constrained deformations based on generalized metaballs 6

General constrained deformations based on generalized metaba...

引用

6th pacific conference on Computing graphics and applications (pacific graphics 98)

作者： Jin, XG Li, YF Peng, QS Zhejiang Univ State Kay Lab CAD&CG Hangzhou 310027 Peoples R China

ISBN: (纸本)0818686200

Space deformation is an important tool in computer animation and shape design. In this paper we propose a new local deformation model based on generalized metaballs. The user specifies a series of constraints, which can be made up of points, lines, surfaces and volumes, their effective radii and maximum displacements, the deformation model creates a generalized metaball for each constraint. Each generalized metaball is associated with a potential function centered on the constraint, the potential function drops from 1 on the constraint to 0 on the effective radius. This deformation model operates on the local space and is independent of the underlining representation of the object to be deformed The deformation can be finely controlled by adjusting the parameters of the generalized metaballs. We also present some extensions and the extended deformation model to include scale and rotation constraints. Experiments show that this deformation model is efficient and intuitive. It can deal with various constraints, which is difficult for traditional deformation model.

关键词： computer animation metaballs implicit surface constrained deformation

来源：评论

学校读者我要写书评

暂无评论

Hierarchical techniques for global illumination computations - recent trends and developments

Hierarchical techniques for global illumination computations...

引用

Proceedings of the 1997 5th pacific conference on computer graphics and applications

作者： Slusallek, Philipp Stamminger, Marc Seidel, Hans-Peter Univ of Erlangen Erlangen Germany

Since the beginning of computer graphics, one of the primary goals has been to create convincingly realistic images of three-dimensional environments that would be impossible to distinguish from photographs of the real scene. The goal to create photo-realistic images has lead to the development of completely new software techniques for dealing with the inherent geometric and optical complexity of real world scenes. This paper gives an overview of advanced algorithms for photo-realistic rendering and in particular discusses hierarchical techniques for global illumination computations.

关键词： Three dimensional computer graphics

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：