自由曲面CAD模型点云数据生成方法研究

The Study on the Method of the Generation of the Point Cloud Data on the Free Surface of CAD Model

在三维测量点云数据与CAD模型配准过程中,设计了两种自由曲面CAD模型点云数据生成方法:等参数采样离散法和基于曲率的采样离散法。应用两种方法评价离散化结果:首先将点云数据进行曲面重构,并与原曲面比对;然后与三维测量点云数据进行配准,得到等参数离散间隔及基于曲率的离散密度对重构和配准误差的影响。实验表明:等参数方法和基于曲率的方法,当点云数据密度达到一定值时均对重构和配准没有影响;在同样点云数据的情况下,基于曲率的离散化方法精度高于等参数方法;但在最大重构误差一致时,基于曲率的方法需要的点云数据远小于等参数化方法所需要的。

In 3D point cloud data and CAD model registration process,two methods of the generation of point cloud data on free surface are designed： equal parameter discrete method and curvature-based discrete method.Two methods of evaluating discrete results are applied：firstly the point cloud data is reconstructed and the reconstruction surface is compared with the original one;then the point cloud data registers with measurement point cloud data to obtain the effect of reconstruction and registration errors of the two methods.The experiments show that：when the point cloud data density reaches a certain value,both methods will have no effect on remodeling and registration;in the case of the same point cloud data,the accuracy of the curvature-based method is higher than the other one;but when the maximum reconstruction error is consistent,the number of point cloud data that the curvature-based discrete method requires is much smaller than the equal parameter discrete method requires.