// Create a search tree, use KDTreee for non-organized data.pcl::search::Search<PointXYZRGB>::Ptr tree;if (cloud->isOrganized ()){tree.reset (new pcl::search::OrganizedNeighbor<PointXYZRGB> ());}else{tree.reset (new pcl::search::KdTree<PointXYZRGB> (false));}// Set the input pointcloud for the search treetree->setInputCloud (cloud);//生成法线估计器（OMP是并行计算，忽略）pcl::NormalEstimationOMP<PointXYZRGB, PointNormal> ne;ne.setInputCloud (cloud);ne.setSearchMethod (tree);//设定法线方向（要做差，同向很重要）ne.setViewPoint (std::numeric_limits<float>::max (),    std::numeric_limits<float>::max (), std::numeric_limits<float>::max ());//计算小尺度法线pcl::PointCloud<PointNormal>::Ptr normals_large_scale (new pcl::PointCloud<PointNormal>);ne.setRadiusSearch (scale2);ne.compute (*normals_large_scale);//计算大尺度法线pcl::PointCloud<PointNormal>::Ptr normals_large_scale (new pcl::PointCloud<PointNormal>);ne.setRadiusSearch (scale2);ne.compute (*normals_large_scale);//生成DoN分割器pcl::DifferenceOfNormalsEstimation<PointXYZRGB, PointNormal, PointNormal> don;don.setInputCloud (cloud);don.setNormalScaleLarge (normals_large_scale);don.setNormalScaleSmall (normals_small_scale);//计算法线差PointCloud<PointNormal>::Ptr doncloud (new pcl::PointCloud<PointNormal>);copyPointCloud<PointXYZRGB, PointNormal>(*cloud, *doncloud);don.computeFeature (*doncloud);//生成滤波条件：把法线差和阈值比pcl::ConditionOr<PointNormal>::Ptr range_cond (new pcl::ConditionOr<PointNormal> ());range_cond->addComparison (pcl::FieldComparison<PointNormal>::ConstPtr (new pcl::FieldComparison<PointNormal> ("curvature", pcl::ComparisonOps::GT, threshold)));//生成条件滤波器,输入滤波条件和点云pcl::ConditionalRemoval<PointNormal> condrem (range_cond);condrem.setInputCloud (doncloud);//导出滤波结果pcl::PointCloud<PointNormal>::Ptr doncloud_filtered (new pcl::PointCloud<PointNormal>);condrem.filter (*doncloud_filtered);//欧式聚类~~~（略）