一种改进的快速定位非Delaunay三角形的逐点插入算法
An Improved Algorithm for the Rapid Localization of Non-Delaunay Triangles through Point-by-Point Insertion
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摘要: 逐点插入算法是计算机图形学复杂表面构建时常用的Delaunay三角化方法, 但节点插入时需要遍历全局三角网格, 存在时间效率较低的问题. 为了优化时间复杂度, 提出快速定位非Delaunay三角形的逐点插入算法. 根据Delaunay三角形的基础性质, 提出并证明了非Delaunay三角形依次相邻定理和最近点为嫌疑点定理, 并基于定理快速定位非Delaunay三角形; 然后分析并解决节点规模庞大且分布密度不均匀时的局部坏死现象, 提出改进的不需要更新遍历阈值的逐点插入算法, 通过对不同分布特征和数量规模的二维点集进行测试, 其时间复杂度在理想情况下可以达到O(NlogN). 对于随机生成的点集, 相较于传统优化算法, 所提算法三角化100万点的时间效率提升达到了46.96%, 且用时与点数更接近线性关系. 实验结果表明, 与Bowyer-Watson算法、传统优化算法相比, 所提算法在三角化效果完全一致的情况下显著提高了时间效率, 且对不同规模和分布特征的数据集均具有良好的适应性和鲁棒性.Abstract: The incremental insertion algorithm is a commonly used Delaunay triangulation method for constructing complex surfaces in computer graphics. However, inserting nodes requires traversing the entire global triangular mesh, which leads to low time efficiency. To optimize the time complexity, a fast method for locating non-Delaunay triangles in incremental insertion algorithms is proposed. Based on the fundamental properties of Delaunay triangles, the “Adjacent Non-Delaunay Triangle Theorem” and the “Nearest Point as Suspect Theorem” are introduced and proven, which facilitate the rapid identification of non-Delaunay triangles. Furthermore, the issue of local necrosis occurring in scenarios with large node scales and uneven distribution density is analyzed and resolved, introducing an improved incremental insertion algorithm that does not require updating the traversal threshold. Tests conducted on two-dimensional point sets with various distribution characteristics and sizes show that the time complexity can ideally reach O(NlogN). For randomly generated point sets, compared to traditional optimized algorithms, the proposed algorithm achieves a 46.96% improvement in time efficiency for triangulating one million points, and the time usage is closer to a linear relationship with the number of points. Experimental results indicate that the proposed algorithm significantly enhances time efficiency while maintaining identical triangulation outcomes compared to the Bowyer-Watson algorithm and traditional optimized algorithms. It also demonstrates good adaptability and robustness across datasets of varying scales and distribution characteristics.