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Shape correspondence for cel animation based on a shape association graph and spectral matching

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Computational Visual Media 2023年第3期9卷 633-656页

作者： Shaolong Liu Xingce Wang Xiangyuan Liu zhongke wu Hock Soon Seah Beijing Normal University Beijing 100875China Nanyang Technological University Singapore 639798Singapore

We present an effective spectral matching method based on a shape association graph for finding region correspondences between two cel animation *** formulate the correspondence problem as an adapted quadratic assignment problem,which comprehensively considers both the intrinsic geometric and topology of regions to find the globally optimal *** simultaneously represent the geometric and topological similarities between regions,we propose a shape association graph(SAG),whose node attributes indicate the geometric distance between regions,and whose edge attributes indicate the topological distance between combined region *** convert topological distance to geometric distance between geometric objects with topological features of the pairs,and introduce Kendall shape space to calculate the intrinsic geometric *** utilizing the spectral properties of the affinity matrix induced by the SAG,our approach can efficiently extract globally optimal region correspondences,even if shapes have inconsistent topology and severe *** is also robust to shapes undergoing similarity transformations,and compatible with parallel computing techniques.

关键词： cel animation shape correspondence shape association graph(SAG) spectral matching quadratic assignment Kendall shape space

REGION-BASED ACTIVE CONTOUR DRIVEN BY GLOBAL INTENSITY FITTING ENERGY

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Journal of Electronics(China) 2010年第4期27卷 480-489页

作者： Tian Yun Zhou Mingquan wu zhongke Wang Xingce College of Information Science ＆ Technology Beijing Normal University Beijing 100875 China

In this paper, we present a novel region-based active contour model based on global in-tensity fitting energy in a variational level set framework. Meanwhile, an internal energy term is in-troduced, and it forces the level set function to be close to a signed distance function. Image global information utilized efficiently makes the proposed model insensitive to noise, and the introduced penalty term can avoid the costly re-initialization for the evolving level set function, which not only speeds up the contour evolvement, but also improves accuracy of the final contour. Comparisons with other classical region-based models, such as Chan-Vese model and Region-Scalable Fitting (RSF) model, show the advantages of our model in terms of efficiency and accuracy. Moreover, the model is robust to noise.

关键词： Region-based active contours Internal energy Global energy Level set Re-initialization

BUILDING A UNIFIED PRODUCT MODEL WITH COMPLEX METHOD

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Chinese Journal of Aeronautics 1996年第2期9卷 111-121页

作者： wu zhongke wu Junheng (CAD/CAM Research Group, School of Space Technology, Beijing Universityof Aeronautics and Astronautics, Beijing, China, 100083) CAD / CAM Research Group School of Space Technology Beijing Univ. Aero. and Astronaut. Beijing 100083 China

After undergoing wireframe modeling, surface modeling and solid modeling, a unified product model, which holds a variety of constraints in engineering, supports design process, and unifies the wire frame, surface modeling, and solid modeling,is a general tendency of modeling technology. A discussion is presented here on how tobuild a unified product model by using the complex method. The concept of complex inalgebraic topology is introduced into the model and a new B-REP representation of thenon-manifold model is given --Identification Edge Structure. Based on it, some basicoperators and high-level operators are built. The model has a rigorous mathematicalbasis, and is flexible and easy to extend, and holds the lamina face, lamina edge andlamina vertex. As a result, the variety of constraints in engineering, such as parametricconstraints, optimization methods, fuzzy constraints, artificial intelligent, etc., can beadded to the system. The model may form the kernel for the implementation of the nextgeneration CAD system --intelligent CAD system.

关键词： computer aided design models polyhedrons

Stable and realistic crack pattern generation using a cracking node method

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Frontiers of Computer Science 2018年第4期12卷 777-797页

作者： Juan ZHANG Fuqing DUAN Mingquan ZHOU Dongcan JIANG Xuesong WANG zhongke wu Youliang HUANG Guoguang DU Shaolong LIU Pengbo ZHOU Xiangang SHANG College of Computer Science and Technology Beijing Normal University Beijing 100875 China College of Art and Communication Beijing Normal University Beijing 100875 China School of Electronics Engineering and Computer Science Peking University Beijing 100871 China

This paper presents a method for simulating surface crack patterns appearing in ceramic glaze, glass, wood and mud. It uses a physically and heuristically combined method to model this type of crack pattern. A stress field is defined heuristically over the triangle mesh of an object. Then, a first-order quasi-static cracking node method （CNM） is used to model deformation. A novel combined stress and energy combined crack criterion is employed to address crack initiation and propagation separately according to physics. Meanwhile, a highest-stress-first rule is applied in crack initiation, and a breadth-first rule is applied in crack propagation. Finally, a local stress relaxation step is employed to evolve the stress field and avoid shattering artifacts. Other related issues are also discussed, such as the elimination of quadra- ture sub-cells, the prevention of parallel cracks and spurious crack procession. Using this method, a variety of crack patterns observed in the real world can be reproduced by changing a set of parameters. Consequently, our method is robust because the computational mesh is independent of dynamic cracks and has no sliver elements. We evaluate the realism of our results by comparing them with photographs of realworld examples. Further, we demonstrate the controllability of our method by varying different parameters.

关键词： crack pattern generation fracture simulation physically-based extend finite element method crack nodemethod

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心脑血管三维分割研究进展

计算机辅助设计与图形学学报 2012年第7期24卷 839-851页

作者：田沄周明全武仲科北京师范大学信息科学与技术学院北京100875

心脑血管疾病是严重威胁人类健康的常见疾病,居各种死亡病因之首.分割作为后续血管三维可视化的关键环节,对于相关疾病的辅助诊疗具有重要意义.鉴于心脑血管位置的特殊性、形态的复杂性及其灰度信息的多变性,对其进行分割仍是一个具有... 详细信息

心脑血管疾病是严重威胁人类健康的常见疾病,居各种死亡病因之首.分割作为后续血管三维可视化的关键环节,对于相关疾病的辅助诊疗具有重要意义.鉴于心脑血管位置的特殊性、形态的复杂性及其灰度信息的多变性,对其进行分割仍是一个具有挑战性的课题.文中对当前基于磁共振血管造影术(magnetic resonance angiograph,MRA)和CT血管造影术(computed tomographic angiography,CTA)图像的三维心脑血管分割算法进行了回顾和总结.首先对包括模式识别、基于管状结构的分割、基于中心线的分割和基于活动轮廓模型分割4类技术进行了讨论;进而给出了每类技术的优缺点、适用范围及待改进之处;最后,探讨了该领域研究的发展方向及应注意的问题.

关键词：心脑血管三维分割血管特征血管抽取

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基于离散形状空间的表情编辑方法

中国科技论文 2023年第7期18卷 722-728页

作者：刘娜武仲科王醒策张丹吕辰雷北京师范大学人工智能学院北京100875 青海师范大学计算机学院西宁810000 南洋理工大学计算机学院新加坡999002

针对人脸表情编辑中受表情姿态影响以及素描和漫画样本量少、训练样本不充分的问题,提出了一种基于离散形状空间(Kendall形状空间)的黎曼框架,其能够利用非线性手段解决人脸表情编辑中存在的数据局限问题,同时能实现中间插值和外延。其... 详细信息

针对人脸表情编辑中受表情姿态影响以及素描和漫画样本量少、训练样本不充分的问题,提出了一种基于离散形状空间(Kendall形状空间)的黎曼框架,其能够利用非线性手段解决人脸表情编辑中存在的数据局限问题,同时能实现中间插值和外延。其核心思想为首先基于人脸特征点构建离散形状空间中表示,在形状空间中实现基于图像的三维人脸建模,其次通过形状空间上的工具获得表情编辑三维模型,最后通过三维模型控制二维漫画或素描,实现基于图像的人脸表情插值和表情外延。Kendall形状空间能够消除平移、缩放和旋转等刚性变换,因此提出的表情编辑方法对面部姿势鲁棒。实验结果表明,该方法能有效且自动地实现漫画和素描表情插值和表情延拓,并保留原图像的真实感。同时,与深度学习方法相比,提出的方法避免了构建漫画和素描训练集的复杂性。

关键词：人脸表情编辑表情外延离散形状空间漫画素描

基于模糊距离的红外图像小目标的精准匹配算法研究

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北京师范大学学报（自然科学版） 2013年第6期49卷 582-585页

作者：丁银军武仲科山东丝绸纺织职业学院山东淄博255300 北京师范大学信息科学与技术学院北京100875

提出了一种基于模糊距离的红外图像小目标的精准匹配算法.该算法从红外图像中获取特征点,以特征点为中心选取参考模板,利用特征模糊距离熵对小目标特征进行扩展,克服由于目标滑动造成的定位误差较大的弊端.实验结果表明,该算法很好的解... 详细信息

提出了一种基于模糊距离的红外图像小目标的精准匹配算法.该算法从红外图像中获取特征点,以特征点为中心选取参考模板,利用特征模糊距离熵对小目标特征进行扩展,克服由于目标滑动造成的定位误差较大的弊端.实验结果表明,该算法很好的解决了红外图像特征目标跟踪技术中的跟踪点滑动和漂移问题,并满足实时性要求,鲁棒性稳定.

关键词：红外图像目标跟踪特征匹配

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球B样条曲线结合树状结构的脑血管表示模型

计算机辅助设计与图形学学报 2013年第4期25卷 541-549页

作者：解立志周明全武仲科田沄北京师范大学信息科学与技术学院北京100875

针对分割之后的脑血管体数据场,提出基于球B样条曲线结合树状结构的表示模型.该模型中主要分为3个步骤表示脑血管:首先采用Hessian矩阵结合弹性球的方法获取脑血管的中心线和半径信息,可提高中心线的求取精度并且在中心线的求取过程中... 详细信息

针对分割之后的脑血管体数据场,提出基于球B样条曲线结合树状结构的表示模型.该模型中主要分为3个步骤表示脑血管:首先采用Hessian矩阵结合弹性球的方法获取脑血管的中心线和半径信息,可提高中心线的求取精度并且在中心线的求取过程中即可获得半径;然后对获得的中心线和半径进行树状重构,得到符合血管的形态拓扑结构,便于对脑血管进行遍历;最后对重构之后的每一分支血管采用球B样条曲线的方式来描述,以对脑血管病变区域进行检测,并能针对不同大小的显示窗口采用多尺度方式绘制.实验结果表明,文中模型在脑血管的显示、病灶检测等方面具有极大优势.

关键词：血管重构球B样条曲线中心线提取树形结构

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数据配准的颅骨面貌复原方法

计算机辅助设计与图形学学报 2011年第4期23卷 607-614页

作者：税午阳周明全武仲科邓擎琼北京师范大学信息科学与技术学院北京100875

颅骨面貌复原技术在法医刑侦领域具有重要应用,为了估计给定颅骨的未知面貌,提出点云配准与五官(鼻、眼睛、嘴)配准结合的颅骨面貌复原框架及基于软组织厚度的评价方法.首先构建颅面数据库并进行坐标校正;然后确定配准点集及其对应关系... 详细信息

颅骨面貌复原技术在法医刑侦领域具有重要应用,为了估计给定颅骨的未知面貌,提出点云配准与五官(鼻、眼睛、嘴)配准结合的颅骨面貌复原框架及基于软组织厚度的评价方法.首先构建颅面数据库并进行坐标校正;然后确定配准点集及其对应关系,采用ICP算法和薄板样条函数两次配准实现参考颅骨与待复原颅骨的精确配准,并将参考模型的软组织厚度作为待复原颅骨的软组织厚度实现面貌初步复原;最后提出一种五官配准方法以提高面貌复原的准确性.提出基于软组织厚度比较的评价方法来验证面貌复原结果的正确性.实验结果证明,文中方法可以有效地实现给定颅骨的面貌估计.

关键词：面貌复原软组织厚度非刚性配准五官配准