激光扫描点云法矢精确计算与表面光顺方法  

Accurate Normal Calculating and Surface Smoothing of Laser-Scanned Point Clouds

作　　者：李明磊[1] 张蕊[1,2] 李广云[1] 

机构地区：[1]信息工程大学导航与空天目标工程学院,郑州450001 [2]华北水利水电大学软件学院,郑州450001

出　　处：《计算机辅助设计与图形学学报》2015年第7期1153-1161,共9页Journal of Computer-Aided Design & Computer Graphics

基　　金：国家自然科学基金(41274014);航天器精密测量基金项目(2014-3;2014-5)

摘　　要：为在光顺的同时保持特征,在精确计算点云表面法矢的基础上,提出附加约束的双边滤波器光顺方法.首先考虑激光扫描点云分布特点对其进行预采样处理,提高法矢估算初值的精度;然后利用抗差最小二乘拟合提高法矢估算精度,并基于拟合中误差和点间距离构造双边滤波器对法矢进行进一步修正,得到较为精确的法矢估算结果;最后通过分析传统双边滤波器存在的问题,引入"噪声度"概念,基于噪声度和点间距离构造双边滤波器,并附加法矢和预测距离以区分拐角特征.实验结果表明了方法的特征保持能力和高效性.In order to preserve feature while smoothing, a new bilateral filter with constraints is proposed on the basis of precise calculation of surface normal vectors. To get accurate normal vectors calculating results, a pre-sampling method is organized firstly to increase normal pre-estimating accuracy considering the char- acteristics of laser-scanned point clouds data. Robust least-squares estimation method is applied to increase normal estimation accuracy. And a new bilateral filter based on mean square error and distance of neighbor points is constructed. To deal with the problems of traditional bilateral filter used in smoothing, a new con- cept of＂noise degree＂ is introduced. Based on noise degree and distance of neighbor points, a bilateral filter with constraints of normal vectors intersection angles and prediction distance of neighbor points is constru- cted. Experimental results demonstrate the feature-preserving ability and high efficiency of the algorithm.

关 键 词：激光点云 法矢估算 双边滤波器 抗差估计 表面光顺 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]