PCL 点云法向估计

void Example::normal_est(pcl::PointCloud<PointType>::Ptr& cloud, pcl::PointCloud<pcl::Normal>::Ptr& point_n)
{
    pcl::search::KdTree<PointType>::Ptr tree(new pcl::search::KdTree<PointType>);
    tree->setInputCloud(cloud);
    // comput the points normal
    pcl::NormalEstimation<pcl::PointXYZ, pcl::Normal> normEst;
    pcl::PointCloud<pcl::Normal>::Ptr normals(new pcl::PointCloud<pcl::Normal>);
    normEst.setInputCloud(cloud);
    normEst.setSearchMethod(tree);
    normEst.setKSearch(15);
    normEst.compute(*normals);
    point_n = normals;
}