pcl形态学滤波器实现地面点分割

ProgressiveMorphologicalFilter类实现了A Progressive Morphological Filter for Removing Nonground Measurements from Airborne LIDAR Data文章中的算法，下面用一个例子演示其用法：

#include <iostream>#include <pcl/io/pcd_io.h>#include <pcl/point_types.h>#include <pcl/filters/extract_indices.h>#include <pcl/segmentation/progressive_morphological_filter.h>intmain(int argc, char** argv){    pcl::PointCloud<pcl::PointXYZ>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZ>);    pcl::PointCloud<pcl::PointXYZ>::Ptr cloud_filtered(new pcl::PointCloud<pcl::PointXYZ>);    pcl::PointIndicesPtr ground(new pcl::PointIndices);    pcl::PCDReader reader;    reader.read<pcl::PointXYZ>("samp11-utm.pcd", *cloud);    std::cerr << "Cloud before filtering: " << std::endl;    std::cerr << *cloud << std::endl;    // 创建形态学滤波器对象    pcl::ProgressiveMorphologicalFilter<pcl::PointXYZ> pmf;    pmf.setInputCloud(cloud);    // 设置过滤点最大的窗口尺寸    pmf.setMaxWindowSize(20);    // 设置计算高度阈值的斜率值    pmf.setSlope(1.0f);    // 设置初始高度参数被认为是地面点    pmf.setInitialDistance(0.5f);    // 设置被认为是地面点的最大高度    pmf.setMaxDistance(3.0f);    pmf.extract(ground->indices);    // Create the filtering object    pcl::ExtractIndices<pcl::PointXYZ> extract;    extract.setInputCloud(cloud);    extract.setIndices(ground);    extract.filter(*cloud_filtered);    std::cerr << "Ground cloud after filtering: " << std::endl;    std::cerr << *cloud_filtered << std::endl;    pcl::PointCloud<pcl::PointXYZRGB>::Ptr cloud_filtered_RGB(new pcl::PointCloud<pcl::PointXYZRGB>);    cloud_filtered_RGB->resize(cloud_filtered->size());    cloud_filtered_RGB->is_dense = FALSE;    for (size_t i = 0 ; i < cloud_filtered->points.size() ; ++i)    {        cloud_filtered_RGB->points[i].x = cloud_filtered->points[i].x;        cloud_filtered_RGB->points[i].y = cloud_filtered->points[i].y;        cloud_filtered_RGB->points[i].z = cloud_filtered->points[i].z;        cloud_filtered_RGB->points[i].r = 0;        cloud_filtered_RGB->points[i].g = 255;        cloud_filtered_RGB->points[i].b = 0;    }    pcl::io::savePCDFileBinary("cloud_groud.pcd", *cloud_filtered_RGB);    // 提取非地面点    extract.setNegative(true);    extract.filter(*cloud_filtered);    std::cerr << "Object cloud after filtering: " << std::endl;    std::cerr << *cloud_filtered << std::endl;    pcl::io::savePCDFileBinary("No_groud.pcd", *cloud_filtered);    return (0);}