利用离散平稳小波变换改进NURBS二次曲面拟合方法

为了提高二次曲面的拟合精度,提出了一种基于离散平稳小波变换的NURBS二次曲面的拟合方法。 首先利用格网化方法得到二次曲面模型点云数据的高程图像及其高程序列,其次对此高程序列进行离散平稳小波变换提取出二次曲面模型表面的特征点,最后利用提取的特征点实现高精度NURBS二次曲面拟合。实验结果表明,该方法与NURBS拟合方法相比,球面和圆锥面拟合结果的均方根误差分别降低了55.79%和50.47%,具有较高的拟合精度。

An Improved Method for NURBS Quadric Surface Based on Discrete Stationary Wavelet Transform

In order to improve fitting accuracy of quadric surface,an improved method for the currently recognized NURBS quadric surface method based on discrete stationary wavelet transform was proposed. At first, elevation image of the quadric surface point cloud and elevation sequence were obtained by using the grid method. Then feature points of the quadric surface were extracted from the discrete stationary wavelet transform results of the elevation sequence of the elevation image. Finally, high accuracy NURBS quadric surface was realized by using the extracted feature points. The experimental results showed that compared with NURBS method, the root mean squared errors of fitting results of sphere and cone surface were reduced 55.79% and 50.47% respectively, and it had satisfactory fitting precision.