检索结果-内蒙古大学图书馆

variational numerical methods for solving nonlinear diffusion equations arising in image processing

JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION 2002年第1-2期13卷 217-237页

作者： Handlovicová, A Mikula, K Sgallari, F Slovak Univ Technol Bratislava Dept Math Bratislava 81368 Slovakia Univ Bologna Dept Math I-40127 Bologna Italy

In this paper we give a general, robust, and efficient approach for numerical solutions of partial differential equations (PDEs) arising in image processing and computer vision. The well-established variational computational techniques, namely, finite element, finite volume, and complementary volume methods, are introduced on a common base to solve nonlinear problems in image multiscale analysis. Since they are based on principles like minimization of energy (finite element method) or conservation laws (finite and complemetary volume methods), they have strong physical backgrounds. They allow clear and physically meaningful derivation of difference equations that are local and easy to implement. The variational methods are combined with semi-implicit discretization in scale, which gives favorable stability and efficiency properties of computations. We show here L.-stability without any restrictions on scale steps. Our approach leads finally to solving linear systems in every discrete scale level, which can be done efficiently by fast preconditioned iterative solvers. We discuss such computational schemes for the regularized (in the sense of F. Catte et at., SIAM J. Numer. Anal. 129, 1992, 182-193) Perona-Malik anisotropic diffusion equation (P. Perona and J. Malik, ieee Trans. Pattern Anal. Mach, Intell. 12, 1990, 629-639) and for nonlinear degenerate diffusion equation of mean curvature flow type studied by L. Alvarez et al. (SIAM J. Numer. Anal, 129, 1992, 845-866). (C) 2002 Elsevier Science (USA).

关键词： image processing nonlinear diffusion Perona-Malik equation mean curvature flow level set equation numerical solution linear semi-implicit scheme finite element method finite volume method complementary volume method

来源：评论

学校读者我要写书评

暂无评论

variational, Geometric, and level set methods in computer vision 1

引用

丛书名： Lecture Notes in computer Science

1000年

作者： Nikos Paragios Olivier Faugeras Tony Chan Christoph Schnörr

ISBN: (数字)9783540321095

ISBN: (纸本)9783540293484

Mathematical methods has been a dominant research path in computational vision leading to a number of areas like ?ltering, segmentation, motion analysis and stereo reconstruction. Within such a branch visual perception tasks can either be addressed through the introduction of application-driven geometric ?ows or through the minimization of problem-driven cost functions where their lowest potential corresponds to image understanding. The 3rd ieee workshop on variational, Geometric and level set methods focused on these novel mathematical techniques and their applications to c- puter vision problems. To this end, from a substantial number of submissions, 30 high-quality papers were selected after a fully blind review process covering a large spectrum of computer-aided visual understanding of the environment. The papers are organized into four thematic areas: (i) Image Filtering and Reconstruction, (ii) Segmentation and Grouping, (iii) Registration and Motion Analysis and (iiii) 3D and Reconstruction. In the ?rst area solutions to image enhancement, inpainting and compression are presented, while more advanced applications like model-free and model-based segmentation are presented in the segmentation area. Registration of curves and images as well as multi-frame segmentation and tracking are part of the motion understanding track, while - troducing computationalprocessesinmanifolds,shapefromshading,calibration and stereo reconstruction are part of the 3D track. We hope that the material presented in the proceedings exceeds your exp- tations and will in?uence your research directions in the future. We would like to acknowledge the support of the Imaging and Visualization Department of Siemens Corporate Research for sponsoring the Best Student Paper Award.

关键词： Image Processing and computer vision computer Imaging, vision, Pattern Recognition and Graphics Pattern Recognition Artificial Intelligence Algorithm Analysis and Problem Complexity computer Graphics

来源：评论

学校读者我要写书评

暂无评论

Lens distortion calibration using level sets

引用

3rd International workshop on variational, Geometric, and level set methods in computer vision, VLSM 2005

作者： El-Melegy, Moumen T. Al-Ashwal, Nagi H. Electrical Engineering Department Assiut University Assiut 71516 Egypt

ISBN: (纸本)3540293485

This paper addresses the problem of calibrating camera lens distortion, which can be significant in medium to wide-angle lenses. Our approach is based on the analysis of distorted images of straight lines. We use a PDE-based level set method to find the lens distortion parameters that straighten these lines. One advantage of this method is that it integrates the extraction of image distorted lines and the computation of distortion parameters within one energy functional which is minimized during level set evolution. Some experiments to evaluate the performance of this approach are reported. © Springer-Verlag Berlin Heidelberg 2005.

关键词： Lenses

来源：评论

学校读者我要写书评

暂无评论

Non-rigid shape comparison of implicitly-defined curves

引用

3rd International workshop on variational, Geometric, and level set methods in computer vision, VLSM 2005

作者： Thiruvenkadam, Sheshadri R. Graisser, David Chen, Yunmei University of California Los Angeles CA 90024 United States University of Florida Gainesville FL 32611 United States

ISBN: (纸本)3540293485

We present a novel variational model to find shape-based correspondences between two sets of level curves. While the usual correspondence techniques work with parametrized curves, we use a level-set formulation that enables us to handle curves with arbitrary topology. Given the functions Φ1 : (Ω1 ⊆ IR2) &rarr IR and Φ2 : (Ω2 ⊆ IR2) &rarr IR whose 0-level curves we want to match, we search for a diffeomorphism that minimizes the rate of change of the difference in tangential orientation of the zero-level sets. To make the formulation symmetric and to simplify computations, we map the domains of the level-set functions Φi to a common domain Ω by initial diffeomorphisms that are chosen arbitrarily. We then search for diffeomorphisms from Ω to itself, generating them by flows of certain vector fields on Ω. The resulting correspondences are scale- and rotation-invariant with respect to the curves. We show how this model can be used as a basis to compare curves of different topology. The model was tested on synthetic and MRI cardiac data,with good results. © Springer-Verlag Berlin Heidelberg 2005.

关键词： variational techniques

来源：评论

学校读者我要写书评

暂无评论

level-set based approach to image registration

Level-set based approach to image registration

引用

MMBIA-2000: ieee workshop on Mathematical methods in Biomedical Image Analysis

作者： Vemuri, B.C. Ye, J. Chen, Y. Leonard, C.M. Univ of Florida Gainesville United States

Image registration is an often encountered problem in various fields including medical imaging, computer vision and image processing. In this paper, we present a novel curve evolution approach expressed in a level-set framework to achieve image registration. The key features of our algorithm are, (a) it can account for small and large deformations, (b) it is very fast (unlike most large deformation schemes) and (c) existence and uniqueness of the solution for the evolution model has been established in a Sobolev space. We demonstrate the implementation results on a variety of images including synthetic and real data.

关键词： Medical imaging

来源：评论

学校读者我要写书评

暂无评论

Proceedings of ieee workshop on Applications of computer vision

Proceedings of IEEE Workshop on Applications of Computer Vis...

引用

6th ieee workshop on Applications of computer vision, WACV 2002

ISBN: (纸本)0769518583

The proceedings contain 55 papers. The topics discussed include: face model adaptation using robust matching and active appearance models;retrieving faces by the PIFS fractal code;an experimental evaluation of linear and kernel-based methods for face recognition;multi-sensor super-resolution;automatic detection of signs with affine transformation;knowledge-based registration and segmentation of the left ventricle: a level set approach;mean-shift segmentation with wavelet-based bandwidth selection;robust and efficient detection of non-lint material in cotton fiber samples;a model-driven method of estimating the state of clothes for manipulating it;activity maps for location-aware computing;fingerprint verification using genetic algorithms;and segmentation of myocardium using velocity field constrained front propagation.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Nonlinear shape manifolds as shape priors in level set segmentation and tracking

Nonlinear shape manifolds as shape priors in level set segme...

引用

作者： Prisacariu, Victor Adrian Reid, Ian University of Oxford United Kingdom

ISBN: (纸本)9781457703942

We propose a novel nonlinear, probabilistic and variational method for adding shape information to level set-based segmentation and tracking. Unlike previous work, we represent shapes with elliptic Fourier descriptors and learn their lower dimensional latent space using Gaussian Process Latent Variable Models. Segmentation is done by a nonlinear minimisation of an image-driven energy function in the learned latent space. We combine it with a 2D pose recovery stage, yielding a single, one shot, optimisation of both shape and pose. We demonstrate the performance of our method, both qualitatively and quantitatively, with multiple images, video sequences and latent spaces, capturing both shape kinematics and object class variance. © 2011 ieee.

关键词： Numerical methods

来源：评论

学校读者我要写书评

暂无评论

A variational approach to mapping and localization

A variational approach to mapping and localization

引用

2012 9th Conference on computer and Robot vision, CRV 2012

作者： Hogue, Andrew Khattak, Saad Faculty of Business and IT University of Ontario Institute of Technology Oshawa ON United States

ISBN: (纸本)9780769546834

A fundamental open problem in SLAM is the effective representation of the map in unknown, ambiguous, complex, dynamic environments. Representing such environments in a suitable manner is a complex task. Existing approaches to SLAM use map representations that store individual features (range measurements, image patches, or higher level semantic features) and their locations in the environment. The choice of how we represent the map produces limitations which in many ways are unfavourable for application in real-world scenarios. In this paper, we explore a new approach to SLAM that redefines sensing and robot motion as acts of deformation of a differentiable surface. Distance fields and level set methods are utilized to define a parallel to the components of the SLAM estimation process and an algorithm is developed and demonstrated. The variational framework developed is capable of representing complex dynamic scenes and spatially varying uncertainty for sensor and robot models. © 2012 ieee.

关键词： Mapping

来源：评论

学校读者我要写书评

暂无评论

Diffusion-snakes: combining statistical shape knowledge and image information in a variational framework

Diffusion-snakes: combining statistical shape knowledge and ...

引用

ieee workshop on variational and level set methods in computer vision

作者： D. Cremers C. Schnorr J. Weickert Computer Vision Graphics and Pattern Recognition Group Department of Mathematics and Computer Science University of Mannheim Mannheim Germany

ISBN: (纸本)076951278X

We present a modification of the Mumford-Shah functional and its cartoon limit which allows the incorporation of statistical shape knowledge in a single energy functional. We show segmentation results on artificial and real-world images with and without prior shape information. In the case of occlusion and strongly cluttered background the shape prior significantly improves segmentation. Finally we compare our results to those obtained by a level-set implementation of geodesic active contours.

关键词： Image segmentation level set Active contours Spline Shape control Active shape model Equations Statistical learning computer vision computer graphics

来源：评论

学校读者我要写书评

暂无评论

Stereoscopic segmentation

Stereoscopic segmentation

引用

8th International Conference on computer vision

作者： Yezzi, A.J. Soatto, S. Georgia Institute of Technology Electrical and Computer Engineering 777 Atlantic Dr. N.W. Atlanta GA 30332 United States

We cast the problem of multiframe stereo reconstruction of a smooth shape as the global region segmentation of a collection of images of the scene. Dually, the problem of segmenting multiple calibrated images of an object becomes that of estimating the solid shape that gives rise to such images. We assume that the radiance has smooth statistics. This assumption covers Lambertian scenes with smooth or constant albedo as well as fine homogeneous textures, which are known challenges to stereo algorithms based on local correspondence. We pose the segmentation problem within a variational framework, and use fast level set methods to approximate the optimal solution numerically. Our algorithm does not work in the presence of strong textures, where traditional reconstruction algorithms do. It enjoys significant robustness to noise under the assumptions it is designed for.

关键词： Stereo vision

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：