finish PoseDiff and NBVDataset

utils/pts.py

@@ -2,7 +2,7 @@ import numpy as np
 import open3d as o3d
 
 class PtsUtil:
-    
+
     @staticmethod
     def voxel_downsample_point_cloud(point_cloud, voxel_size=0.005):
         o3d_pc = o3d.geometry.PointCloud()
@@ -14,4 +14,9 @@ class PtsUtil:
     def transform_point_cloud(points, pose_mat):
         points_h = np.concatenate([points, np.ones((points.shape[0], 1))], axis=1)
         points_h = np.dot(pose_mat, points_h.T).T
-        return points_h[:, :3]
+        return points_h[:, :3]
+    
+    @staticmethod
+    def random_downsample_point_cloud(point_cloud, num_points):
+        idx = np.random.choice(len(point_cloud), num_points, replace=False)
+        return point_cloud[idx]