共查询到20条相似文献,搜索用时 78 毫秒
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针对B样条曲面拟合中出现的问题和困难,提出了一种基于行组织的轮廓数据(截面数据)的曲面重建方法。该方法避免了数据点的参数化问题,使得逼近曲面拥有较好的形状和合理的控制顶点数量。该方法的基本思想是:首先构造易于控制的低阶曲面拟合数据点,此曲面称控制曲面,然后利用高次曲面逼近该曲面,此高次曲面称为逼近曲面,为所需要的重建曲面。在曲面重建中利用最佳平方逼近和光顺函数,减少了逼近曲面的控制顶点冗余,较有效地防止了逼近曲面的形状突变和曲面的扭曲,很大程度地提高了曲面的质量。 相似文献
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针对三维切割及多平面重建只能获取组织或器官的几何平面信息,无法将弯曲结构的组织或器官展示在单张图片上的问题,实现了基于多平面重建(MPR)提取轮廓线的冠脉曲面重建(CPR)算法.首先,利用多平面重建获取冠脉轮廓的离散点;然后,对离散点进行Cardinal样条插值,获取平滑的轮廓拟合曲线;其次,沿着感兴趣方向对轮廓线进行投影形成扫描曲面;最后,显示扫描曲面对应的心脏体数据,得到冠脉重建曲面.实验结果表明,在绘制速度上,与三维切割法和三维数据场法相比,冠脉轮廓线提取速度提高了每秒4~6帧,绘制时间较短.在绘制质量上,与三维分割法相比,得到的冠脉曲面成像清晰,结构完整,有助于医师对病变的直观分析,能满足实际临床诊疗需求. 相似文献
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G^1连续任意拓扑曲面的几何重建 总被引:5,自引:0,他引:5
文中算法沿用了 C-T分割算法的基本思想,从任意拓扑类 曲面三解剖分T(P)出发,重建一张G^1连续拼接的分段光滑曲面,用以插值T(P)的顶点集P及其中各点的法矢,在插值点的法矢没有给定的情况下,引入了“惯量估计”以估算各点的法矢,与Farin的C-T分割算法相比,本算法的结果不依赖于顶点的处理顺序,因而更为合理,其次,它不需要进行控制顶点的初估及修正,而是对多余的自由度进行了合理的分配,使各控制顶点的计算一次完成,由于算法是局部的,因此具有较高的效率。 相似文献
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鉴于多结点样条曲线(MSIC)是一种点点通过的插值样条曲线,因此在多结点样条插值曲线研究的基础上,给出了有理多结点条插值曲线和有理多结点样条插值曲面的定义,并讨论了有理多结点样条的性质,对有理多结 样条曲线和有理多结点样条曲面的光滑拼接问题进行了讨论,此外,还对有理多结点样条在计算机辅助几何设计中的若干应用问题进行了说明。 相似文献
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This paper discusses the problem of constructing C2 quartic spline surface interpolation. Decreasing the continuity of the quartic spline to C2 offers additional freedom degrees that can be used to adjust the precision and the shape of the interpolation surface. An approach to determining the freedom degrees is given, the continuity equations for constructing C2 quartic spline curve are discussed, and a new method for constructing C2 quartic spline surface is presented. The advantages of the new method are that the equations that the surface has to satisfy are strictly row diagonally dominant, and the discontinuous points of the surface are at the given data points. The constructed surface has the precision of quartic polynomial. The comparison of the interpolation precision of the new method with cubic and quartic spline methods is included. 相似文献
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Free-formed or sculptured surfaces in engineering products are frequently constructed from a set of measured 3D data points.C^2-(C^3-)continuity approach is important in this field.This paper presents a method of rectangular interpolation of given 3D data array which is regularly arranged.The interpolation surface which is constructed by tensor product has dsirable properties(second-order or third-order continuity,locality)and is implemented and adjusted easily,Higher order continuity methods are also briefly discussed. 相似文献
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基于三次样条函数的传感器特性曲面二维插值 总被引:7,自引:0,他引:7
在传感器输出、输入和环境参量均存在非线性的情况下,传统校准方法遇到困难,为提供一种提高测量精度的新途径,在接受非线性事实的基础上,采用三次样条函数二维插值,建立起传感器传递特性曲面.通过实例计算显示了一个化学传感器特性曲面.所获得的传感器特性曲面光滑性好,在输入和环境参量2个方向的一阶、二阶导数都连续,更符合传感器实际传递特性. 相似文献
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文章给出了基于C-B 样条的由网格数据产生三角形和四边形曲面片的方
法,C-B 样条是由基底函数{sin t, cos t, t, 1}导出的一种新型样条曲线,它可以克服现在正在
使用的B 样条和有理B 样条为了满足数据网格的拓扑结构而增加多余的控制点,求导求积
分复杂繁琐,阶数过高,从而讨论其连续拼接时增加了困难等缺点,如何将它推广成曲面就
成为一个重要问题。作者利用边-顶点方法构造插值算子,再将这些算子进行凸性组合,将
C-B 样条曲线推广成三角形曲面片和四边形曲面片,它可以用于CAD 的逆向工程中散乱数
据的曲面重构。 相似文献
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This paper discusses the problem of constructing C2 quartic spline surface interpolation. Decreasing the continuity of the quartic spline to C2 offers additional freedom degrees that can be used to adjust the precision and the shape of the interpolation surface. An
approach to determining the freedom degrees is given, the continuity equations for constructing C2 quartic spline curve are discussed, and a new method for constructing C2 quartic spline surface is presented. The advantages of the new method are that the equations that the surface has to satisfy
are strictly row diagonally dominant, and the discontinuous points of the surface are at the given data points. The constructed
surface has the precision of quartic polynomial. The comparison of the interpolation precision of the new method with cubic
and quartic spline methods is included. 相似文献
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利用Bézier曲线的端点插值性质,得到了构造三次插值样条曲线曲面的一种改进的基函数——BB基函数。由BB基函数构造了C1保形三次插值样条曲线;构造了C1双三次插值样条曲面。 相似文献
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The existing methods for visualizing volumetric data are mostly based on piecewise linear models.And all kinds of analysis based on them have to be substituted by coarse interpolations.So both accuracy and reliability of the traditional framework for visualization and analysis of volumetric data are far from our needs of digging information implied in volumetric data fields.In this paper,we propose a novel framework based on a C2-continuous seven-directional box spline,under which reconstruction is of high accuracy and differential computations relative to analysis based on the reconstruction model are accurate.We introduce a polynomial differential operator to improve the reconstruction accuracy.In order to settle the difficulty of evaluating upon the seven-directional box spline,we convert it into B′ezier form and propose effective theories and algorithms of extracting iso-surfaces,critical points and curvatures.Plentiful of examples are also given in this paper to illustrate that the novel framework is suitable for analysis,the improved reconstruction method has high accuracy,and our algorithms are fast and stable. 相似文献
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曲面上的曲线插值是计算机辅助几何设计的重要课题之一.利用可展曲面可与平面贴合的性质,构造一个等距对应将可展曲面展成平面,从而将可展曲面上的曲线插值归结为通常的R2上插值曲线的构造,并证明所得的插值曲线为C1连续.最后以柱面、锥面以及切线曲面为例构造插值曲线,图例显示该算法具有满意的效果. 相似文献