【作者】 刘婷；

【导师】 华顺刚；

【作者基本信息】 大连理工大学 ， 机械设计及理论， 2008， 硕士

【摘要】 图像变形是一种基于变形控制特征,根据一定的变形函数生成平滑、具有真实感的变形效果的图像处理技术。该技术可以被广泛应用在虚拟现实、计算机动画、医学图像处理以及影视娱乐等各个领域。本文对基于特征曲线及移动最小二乘优化方法的图像变形技术进行了研究。研究了基于控制点的移动最小二乘图像变形方法。首先分析了基于控制点的移动最小二乘图像变形方法的数学模型,根据变形需要设置特征控制点。研究了基于点集的仿射、相似以及刚性变换的变形函数,基于变形函数通过移动控制点生成变形后的新图像。并对仿射、相似以及刚性变形效果进行了比较。在基于点集的图像变形方法的基础上,研究了一种基于控制曲线集的移动最小二乘图像变形方法。根据源图像中的形状信息或变形需要来设置关键点,生成三次样条特征曲线,然后移动该特征曲线到新的位置根据变型函数实现图像的变形。推导了基于曲线集的仿射、相似和刚性变形函数,实现图像的真实感变形。为了保持图像变形的实时性,在曲线集的图像变形方法基础上研究了一种基于OpenGL纹理映射的加速算法。对源图像进行网格划分,利用变形函数计算出网格点变形后的坐标,在OpenGL中生成变形后的网格点框架:将变形前的二维图像转化为纹理映射到网格点框架上,从而提高了图像变形速度,达到实时性的变形效果。基于上述图像变形方法的分析研究,开发了一个图像变形处理系统,实现了基于点、基于曲线和基于网格点的移动最小二乘图像变形,每种变形方法中包括仿射、相似和刚性变换三种变形效果。该变形系统利用Visual C++的MFC框架实现了可视化操作界面,用户使用方便。更多还原

【Abstract】 Image deformation is an image processing technique, which creates smooth and realistic deformation results based on deformation control features and definite deformation functions. This technique is widely used in virtual reality, computer animation, medical image processing and movie & TV field.A point-based image deformation method using moving least squares(MLS) is studied. First, point-based MLS mathematic model is analyzed and the feature control points are set according to deformation requirement. The point-based transformation functions are studied to compute afflne, similarity and rigid deformations of image and obtain image deformation results by moving control points. Then comparison of affine, similarity and rigid image deformation results is made.Based on the research above, a MLS image deformation method using control curves is studied. According to shape information or deformation requirement, key points are set to create cubic-spline curves. The curves are moved to new positions to control the deformation of image. Then the transformation functions based on control curves are deduced to compute affine, similarity and rigid deformations of image and realize realistic image deformation results.To keep the real time of image deformation, an accelerated algorithm of curve-based image deformation is implemented by OpenGL texture mapping. The original image is partitioned by grid and the deformed coordinates of every grid vertex are computed. Then deformed image framework is created in OpenGL; 2D image before deformation is translated into texture and mapped to the deformed image framework, which accelerates time cost and realizes the real time of image deformation.A system of image deformation has been exploited based on the above-mentioned methods. It can realize MLS image deformation based on points, curves and grid vertices. Every deformation method concludes affine, similarity and rigid deformations of image. The experimental results show that the system has visual operation interface and makes the operation convenient for users.更多还原