【作者】 倪彤光；

【导师】 顾耀林；

【作者基本信息】 江南大学 ， 计算机应用技术， 2005， 硕士

【摘要】 随着计算机辅助设计与图形学的发展,几何造型技术在许多领域得到了广泛的研究和应用,其中基于散乱点数据的曲面重建及光顺技术是其中一个很重要的内容。本文主要研究散乱点的三角形网格曲面重建和光顺技术,并提出了两个新的方法。在空间散乱点的三角形网格曲面重建方面,基于Voronoi图的Power Crust算法有理论证明。实验表明如果采样充分,重建效果很好,但执行时间过长。本文以Power Crust算法为理论基础,提出了一个新的三维散乱点数据快速曲面重建方法。本文方法是进行曲面重建前先通过一个带边界检测的不均匀降采样过程减少参与运算的采样点,表面特征丰富的区域削减的采样点数远小于特征不丰富的区域,再进行曲面重建,通过实例表明该算法大大加快了散乱点数据的重建速度,而且很好地保持了模型表面的特征,能够较为真实的重建出曲面模型。本文还论述了目前普遍使用的三角形网格曲面光顺方法,在加权均值滤波与拉普拉斯光顺的基础上提出了一种特征保持的混合光顺方法。根据曲面局部变化趋势,将网格顶点分为特征顶点与其他顶点,光顺时分开考虑,试验结果表明本文方法在有效去除噪声和匀化三角形的同时,较好地保留了原网格模型的特征信息。更多还原

【Abstract】 With the development of computer graphics and CAD, geometry modeling is an importantresearch field in the computer graphics. This thesis not only reviews the technology of surfacesreconstruction and mesh smoothing, but also presents two new methods.A fast surface reconstruction algorithm based on Power Crust algorithm is proposed forunorganized points. From sufficient dense sample point set, Power Crust algorithm can reconstructa triangular mesh that is topologically valid and convergent to the original surface. However, thealgorithm is limited in the practical application because of its long running time. A non-uniformdown sampling method with border-estimation is proposed to resample the input data set accordingto local feature before reconstruction. Some instances indicate that this method has greatlypromoted the speed of using scatter data points to finish surface reconstruction, and reallyreconstructed surface model.The paper also proposes a hybrid feature-preserving smoothing method for triangular meshes,which maintians merits of weighted median and Laplacian method. In smoothing process, thefeature vertices weighted differently. For feature vertices the displacement is small and for commonones the displacement is big. After smoothing process, features of the original mesh can beperfectly preserved. Compared with existing methods, this method can efficiently eliminate noisesand preserve features of the original meshes.更多还原