Point Cloud Library PCL learning - the point cloud for common operations

1. How to get pcd file format point cloud point, for example, it is pcl :: PointXYZ or pcl :: PointXYZRGB other types?

#include <pcl/io/pcd_io.h>
#include <pcl/point_types.h>
#include <pcl/point_cloud.h>
#include <pcl/PCLPointCloud2.h>
 
pcl::PCLPointCloud2 cloud;
pcl::PCDReader reader;
reader.readHeader("C:\fandisk.pcd", cloud);
for (int i = 0; i < cloud.fields.size(); i++)
{
    std::cout << cloud.fields[i].name;
}

2. How to achieve similar pcl :: PointCloud :: Ptr and pcl :: PointCloud two classes of conversion?

#include <pcl/io/pcd_io.h>
#include <pcl/point_types.h>
#include <pcl/point_cloud.h>
 
pcl::PointCloud<pcl::PointXYZ>::Ptr cloudPointer(new pcl::PointCloud<pcl::PointXYZ>);
pcl::PointCloud<pcl::PointXYZ> cloud;
cloud = *cloudPointer;
cloudPointer = cloud.makeShared();

3. How to speed stored in ASCII format, that is, you can see pcd Notepad to open the file read speed coordinate data? Pcd is recommended to store the files into Binary format.

#include <pcl/io/pcd_io.h>
#include <pcl/point_types.h>
#include <pcl/point_cloud.h>
#include <pcl/PCLPointCloud2.h>
 
pcl::PointCloud<pcl::PointXYZ>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZ>);
pcl::io::loadPCDFile<pcl::PointXYZ>("C:\office3-after1.pcd", *cloud);
pcl::io::savePCDFileBinary("C:\office3-after21111.pcd", *cloud);

4. How :: PointXYZ type of point cloud specified color in the display to pcl?

#include <pcl/io/pcd_io.h>
#include <pcl/point_types.h>
#include <pcl/point_cloud.h>
#include <pcl/visualization/pcl_visualizer.h>
 
pcl::PointCloud<pcl::PointXYZ>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZ>);
pcl::io::loadPCDFile<pcl::PointXYZ>("C:\office3-after21111.pcd", *cloud);
 
pcl::visualization::PCLVisualizer viewer("pointcloud viewer");
pcl::visualization::PointCloudColorHandlerCustom<pcl::PointXYZ> sig(cloud, 0, 234, 0);
viewer.addPointCloud(cloud, sig, "cloud");
while (!viewer.wasStopped())
{
    viewer.spinOnce();
}

5. How to find the point cloud of x, y, z extreme value?

#include <pcl/io/pcd_io.h>
#include <pcl/point_types.h>
#include <pcl/common/common.h>
pcl::PointCloud<pcl::PointXYZ>::Ptr cloud;
cloud = pcl::PointCloud<pcl::PointXYZ>::Ptr (new pcl::PointCloud<pcl::PointXYZ>);
pcl::io::loadPCDFile<pcl::PointXYZ> ("your_pcd_file.pcd", *cloud);
pcl::PointXYZ minPt, maxPt;
pcl::getMinMax3D (*cloud, minPt, maxPt);

6. How to determine the point cloud points null point, i.e. coordinate values ​​NaN3, and how to point to null point?

#include <pcl/point_types.h>
 
pcl::PointXYZ p_valid;
p_valid.x = 0;
p_valid.y = 0;
p_valid.z = 0;
std::cout << "Is p_valid valid? " << pcl::isFinite(p_valid) << std::endl;
 
pcl::PointXYZ p_invalid;
p_invalid.x = std::numeric_limits<float>::quiet_NaN();
p_invalid.y = 0;
p_invalid.z = 0;
std::cout << "Is p_invalid valid? " << pcl::isFinite(p_invalid) << std::endl;

7. How will remove invalid points from the point cloud?

#include <pcl/point_cloud.h>
#include <pcl/point_types.h>
#include <pcl/filters/filter.h>
 
typedef pcl::PointCloud<pcl::PointXYZ> CloudType;
CloudType::Ptr cloud(new CloudType);
cloud->is_dense = false;
CloudType::Ptr output_cloud(new CloudType);
 
CloudType::PointType p_nan;
p_nan.x = std::numeric_limits<float>::quiet_NaN();
p_nan.y = std::numeric_limits<float>::quiet_NaN();
p_nan.z = std::numeric_limits<float>::quiet_NaN();
cloud->push_back(p_nan);
 
CloudType::PointType p_valid;
p_valid.x = 1.0f;
cloud->push_back(p_valid);
 
std::cout << "size: " << cloud->points.size() << std::endl;
 
std::vector<int> indices;
pcl::removeNaNFromPointCloud(*cloud, *output_cloud, indices);
std::cout << "size: " << output_cloud->points.size() << std::endl;

8. If you know you need to save the serial number of points, how to copy from the origin point to the new point cloud cloud?

#include <pcl/io/pcd_io.h>
#include <pcl/common/impl/io.hpp>
#include <pcl/point_types.h>
#include <pcl/point_cloud.h>
 
pcl::PointCloud<pcl::PointXYZ>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZ>);
pcl::io::loadPCDFile<pcl::PointXYZ>("C:\office3-after21111.pcd", *cloud);
pcl::PointCloud<pcl::PointXYZ>::Ptr cloudOut(new pcl::PointCloud<pcl::PointXYZ>);
std::vector<int > indexs = { 1, 2, 5 };
pcl::copyPointCloud(*cloud, indexs, *cloudOut);

9. How to remove and add points from the point cloud?

#include <pcl/io/pcd_io.h>
#include <pcl/common/impl/io.hpp>
#include <pcl/point_types.h>
#include <pcl/point_cloud.h>
 
pcl::PointCloud<pcl::PointXYZ>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZ>);
pcl::io::loadPCDFile<pcl::PointXYZ>("C:\office3-after21111.pcd", *cloud);
pcl::PointCloud<pcl::PointXYZ>::iterator index = cloud->begin();
cloud->erase(index);//删除第一个
index = cloud->begin() + 5;
cloud->erase(cloud->begin());//删除第5个
pcl::PointXYZ point = { 1, 1, 1 };
//在索引号为5的位置1上插入一点，原来的点后移一位
cloud->insert(cloud->begin() + 5, point);
cloud->push_back(point);//从点云最后面插入一点
std::cout << cloud->points[5].x;//输出1

If too many points to delete recommend using the above method to copy the new point cloud, and then assigned to the origin of the cloud, if you want to add a lot of points, it is recommended to resize, and then add a loop to the point where the cloud.
How 10.PointCloud and PCLPointCloud2 type conversion?

#include <pcl/io/pcd_io.h>
#include <pcl/point_types.h>
 
pcl::PointCloud<pcl::PointXYZ>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZ>);
pcl::PCLPointCloud2 cloud2;
pcl::io::loadPCDFile("C:\office3-after21111.pcd", cloud2);
pcl::fromPCLPointCloud2(cloud2, *cloud);
pcl::toPCLPointCloud2(*cloud, cloud2);

Reproduced in http://www.manongjc.com/article/93751.html