PCL点云库——平面模型分割

平面模型分割

　　平面模型分割是采用随机采样一致性对点云拟合出一个平面，将点到该平面的距离小于“距离阈值”的点都作为内点，大于“距离阈值”的点都作为外点。可以通过设置参数选择保留内点还是外点。

//****平面模型分割****//
 
#include <pcl/io/pcd_io.h>
#include <pcl/segmentation/sac_segmentation.h>
#include <pcl/filters/extract_indices.h>
#include <pcl/visualization/cloud_viewer.h>  

int
main(int argc, char** argv)
{
	pcl::PointCloud<pcl::PointXYZ>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZ>);
	pcl::PointCloud<pcl::PointXYZ>::Ptr cloud_segmented(new pcl::PointCloud<pcl::PointXYZ>());
	pcl::PointIndices::Ptr inliers(new pcl::PointIndices);
	pcl::ModelCoefficients::Ptr coefficients(new pcl::ModelCoefficients);
	// 填入点云数据  
	pcl::io::loadPCDFile("milk_cartoon_all_small_clorox.pcd", *cloud);

	pcl::SACSegmentation<pcl::PointXYZ> seg; //创建分割对象
	seg.setOptimizeCoefficients(true);	//可设置是否优化系数
	seg.setModelType(pcl::SACMODEL_PLANE);
	seg.setMethodType(pcl::SAC_RANSAC);
	seg.setMaxIterations(100);
	seg.setDistanceThreshold(0.01);//距离阈值
	seg.setInputCloud(cloud);
	seg.segment(*inliers, *coefficients);
	
	//分割提取
	pcl::ExtractIndices<pcl::PointXYZ> extract;
	extract.setInputCloud(cloud);
	extract.setIndices(inliers);
	pcl::PointCloud<pcl::PointXYZ>::Ptr temp_in(new pcl::PointCloud<pcl::PointXYZ>());
	pcl::PointCloud<pcl::PointXYZ>::Ptr temp_out(new pcl::PointCloud<pcl::PointXYZ>());
	extract.setNegative(false); //参数为false时输出为平面点云，为true时输出为除平面之外的点云
	extract.filter(*temp_in);
	extract.setNegative(true);
	extract.filter(*temp_out);
	cloud_segmented = temp_in;  //切换temp_in与temp_out，选择平面内或外的点云

	if (inliers->indices.size() == 0)
	{
		PCL_ERROR("Could not estimate a planar model for the given dataset.");
		return (-1);
	}
	std::cerr << "Model coefficients: " << coefficients->values[0] << " "
		<< coefficients->values[1] << " "
		<< coefficients->values[2] << " "
		<< coefficients->values[3] << std::endl;  //打印平面模型的参数（以ax+by+cz+d=0的形式），四个参数分别为a、b、c、d

	//可视化
	pcl::visualization::PCLVisualizer viewer("PCLVisualizer");
	viewer.initCameraParameters();

	int v1(0);
	viewer.createViewPort(0.0, 0.0, 0.5, 1.0, v1);
	viewer.setBackgroundColor(128.0 / 255.0, 138.0 / 255.0, 135.0 / 255.0, v1);
	viewer.addText("Cloud before segmenting", 10, 10, "v1 test", v1);
	viewer.addPointCloud<pcl::PointXYZ>(cloud, "cloud", v1);

	int v2(0);
	viewer.createViewPort(0.5, 0.0, 1.0, 1.0, v2);
	viewer.setBackgroundColor(128.0 / 255.0, 138.0 / 255.0, 135.0 / 255.0, v2);
	viewer.addText("Cloud after segmenting", 10, 10, "v2 test", v2);
	viewer.addPointCloud<pcl::PointXYZ>(cloud_segmented, "cloud_segmented", v2);

	viewer.setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 3, "cloud");
	viewer.setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 3, "cloud_segmented");

	while (!viewer.wasStopped())
	{
		viewer.spinOnce(100);
		boost::this_thread::sleep(boost::posix_time::microseconds(100000));
	}
	return (0);
}