import open3d as o3d
import numpy as np

pcd = o3d.io.read_point_cloud("pointcloud.pcd")

# 1. 计算法线
pcd.estimate_normals(search_param=o3d.geometry.KDTreeSearchParamKNN(k=30))

# 2. 提取FPFH特征
fpfh = o3d.pipelines.registration.compute_fpfh_feature(
    pcd,
    o3d.geometry.KDTreeSearchParamKNN(k=50)
)

# fpfh.data 是 (33, N) 的矩阵，每列是一个点的33维FPFH描述子
print(fpfh.data.shape)  # (33, N)