opem3d:例程二：体素降采样

        体素降采样使用常规体素网格从输入点云创建均匀的缩减采样点云。它通常用作许多点云处理任务的预处理步骤。该算法分两步运行：

1. 点被收集到体素中。

2. 把点云分配在三维网格中取平均值

   import open3d as o3d
   import numpy as np
   print("Load a ply point cloud, print it, and render it")
   pcd = o3d.io.read_point_cloud("fragment.ply")
   print(pcd)
   print(np.asarray(pcd.points))
   o3d.visualization.draw_geometries([pcd],
                                     zoom=0.3412,
                                     front=[0.4257, -0.2125, -0.8795],
                                     lookat=[2.6172, 2.0475, 1.532],
                                     up=[-0.0694, -0.9768, 0.2024])
   
   #体素降采样
   print("Downsample the point cloud with a voxel of 0.05")
   downpcd = pcd.voxel_down_sample(voxel_size=0.05) #voxel_down_sample 把点云分配在三维的网格中取平均值
   o3d.visualization.draw_geometries([downpcd],
                                     zoom=0.3412,
                                     front=[0.4257, -0.2125, -0.8795],
                                     lookat=[2.6172, 2.0475, 1.532],
                                     up=[-0.0694, -0.9768, 0.2024])
   
   

生成的结果：