核燃料棒点云圆柱拟合及三维重建方法研究

Research on Point Cloud Cylinder Fitting and 3D Reconstruction Method of Nuclear Fuel Rod

完整的核燃料棒几何形貌是核电站正常运行的重要依据,当前利用结构光进行水下燃料棒扫描时,因受水中杂质和燃料棒表面反光影响,会导致大量点云噪点的产生,进而影响检测形貌的精准重构。为此,文中提出一种高效准确的方法以实现对燃料棒形貌的三维立体重建。首先借助拓扑原理将圆柱点云数据分别进行最小二乘法直线拟合和平面拟合,进而利用直线方向向量和平面法向量实现点云空间坐标的转换;接着利用误差阈值搜索法计算圆柱点云的圆心和圆柱半径;最后将圆柱点云进行可视化处理,从而实现曲面三维重建。实验结果表明该方法拟合圆柱直径精度可达0.12 mm,圆柱间夹角精度可达0.4°,验证了该方法的有效性。

The complete nuclear fuel rod geometry is an important basis for the normal operation of nuclear power plants.At present, when using structured light for underwater fuel rod scanning, due to the influence of impurities in the water and the surface of the fuel rod, a large number of point cloud noise will be generated, which will affect the accurate reconstruction of the detected shape. This paper proposes an efficient and accurate method to achieve three-dimensional reconstruction of the fuel rod morphology. Firstly, the cylindrical point cloud data is subjected to least squares straight line fitting and plane fitting by means of topological principle, and then the linear direction vector and plane normal vector are used to realize the transformation of point cloud space coordinates. Then the error threshold search method is used to calculate the center of the cylindrical point cloud and the radius of the cylinder. Finally, the cylindrical point cloud is visualized to realize the three-dimensional reconstruction of the surface. The experimental results show that the accuracy of the method can be as high as 0.12 mm, and the accuracy of the angle between the cylinders can reach 0.4°. The effectiveness of the method is verified.