基于移动最小二乘的二维形状变形和形状插值控制

发布时间：2018-01-11 06:03

本文关键词：基于移动最小二乘的二维形状变形和形状插值控制　出处：《浙江工商大学》2014年硕士论文　论文类型：学位论文

【摘要】：计算机动画是一种利用人眼视觉暂留效应原理,通过连续播放一系列静止的图画,让人在视觉上产生景物运动错觉的技术。它是计算机图形学与艺术相结合的产物,目前广泛应用于影视特技制作、建筑装潢设计、商业广告等领域。二维形状变形和二维形状插值是计算机动画中的重要技术。在二维形状变形技术中,研究人员最近提出了一种基于移动最小二乘的变形方法。该方法允许用户通过点和线来实时操作二维角色,并且能够生成光滑且视觉真实的角色变形结果。但是,该方法采用欧氏距离作为变形约束权值,而没有考虑角色形状的拓扑结构,导致可能产生扭曲的变形结果。在二维形状插值技术中,保刚性插值算法能够产生比较自然的形状过渡效果。但是,在这类方法中,形状的中间过渡序列一般完全由源和目标形状决定,而缺乏有效手段让用户可以控制中间过渡序列的产生。针对上述问题,分别提出了一种考虑拓扑结构的移动最小二乘卡通角色变形方法和一种基于移动最小二乘的形状插值控制方法。主要内容包括： (1)提出了一种考虑拓扑结构的移动最小二乘卡通角色变形方法。首先,基于用户的交互约束配置,在角色形状上最小化拉普拉斯能量函数,得到一组权值,我们称该组权值为“调和权值”。然后,以调和权值作为变形约束权值,对卡通角色进行移动最小二乘变形。由于“调和权值”考虑了形状的拓扑结构并且以一种局部扩散的方式传播了用户交互约束的变形影响,最终有效避免了可能的变形扭曲。此外,设计了一种保面积的移动最小二乘变形方法,适用于不可压缩角色物体的变形。实验结果表明,新方法有效避免了可能的形状扭曲,能够实时地产生光滑且视觉真实的卡通角色变形效果。 (2)提出了一种基于移动最小二乘的形状插值控制方法。该方法允许用户通过若干个控制点来控制形状的插值过渡序列。首先,以保刚性插值算法为基础,生成源和目标形状之间的初始过渡序列。然后,为了控制形状的过渡序列,用户根据需要在源形状上预放置若干个控制点。最后,在选定的中间帧上,用户编辑这些控制点,算法基于移动最小二乘变形技术自动把用户控制光滑地传播到整个形状以及相邻帧上,最终实现用户控制的形状插值过渡。实验结果表明,新方法允许用户通过简单直观的交互获得视觉自然的插值效果。
[Abstract]:Computer animation is a series of static pictures by using the principle of human visual temporary effect. It is a combination of computer graphics and art. It is widely used in the field of film and television stunts, architectural decoration design, commercial advertising and so on. Two-dimensional shape deformation and two-dimensional shape interpolation are important techniques in computer animation. Researchers have recently proposed a new method based on moving least squares, which allows users to use points and lines to manipulate two-dimensional roles in real time. And it can produce smooth and visual real character deformation results. However, the Euclidean distance is used as the weight of deformation constraints without considering the topological structure of role shape. In two-dimensional shape interpolation, the rigid-preserving interpolation algorithm can produce a more natural shape transition effect. However, in this kind of method. The intermediate transition sequence of shape is generally determined by the shape of source and target, and there is a lack of effective means for user to control the generation of intermediate transition sequence. In order to solve the above problems, a moving least square cartoon character deformation method and a shape interpolation control method based on moving least squares are proposed respectively. The main contents are as follows: Firstly, based on the user's interaction constraint configuration, the Laplace energy function is minimized in the shape of the character. We get a set of weights, which we call "harmonic weights". Then, we take harmonic weights as the weight of deformation constraints. Because the "harmonic weight" takes into account the topological structure of the shape and propagates the deformation effect of user interaction constraints in a local diffusion way. Finally, the possible distortion distortion is effectively avoided. In addition, a moving least square deformation method with conserved area is designed, which is suitable for the deformation of incompressible bodies. The experimental results show that the proposed method is suitable for the deformation of incompressible bodies. The new method can effectively avoid the possible shape distortion, and can produce smooth and visual real-time cartoon character distortion in real-time. (2) A shape interpolation control method based on moving least squares is proposed, which allows users to control shape interpolation transition sequences through several control points. Firstly, it is based on rigid preserving interpolation algorithm. An initial transition sequence between the source and the target shape is generated.; then, in order to control the transition sequence of the shape, the user prepositions several control points on the source shape as needed. Finally, on the selected intermediate frame. The user edits these control points and the algorithm automatically propagates the user control smoothly to the whole shape and adjacent frames based on the moving least square deformation technique. Finally, the user controlled shape interpolation transition is realized. Experimental results show that the new method allows users to obtain natural visual interpolation effects through simple and intuitive interaction.
【学位授予单位】：浙江工商大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP391.41

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