how to remove floor surface in the pointcloud2 data with the pcl_ros

Question

first, thanks for reading. now i am trying to do remove floor in the point cloud data,

this is a code that i wrote to remove the floor point cloud.

#include <iostream>
#include <cmath>
#include <vector>
#include <ros/ros.h>
#include <sensor_msgs/PointCloud2.h>
#include <pcl_ros/point_cloud.h>
#include <pcl/point_types.h>
#include <pcl_conversions/pcl_conversions.h>
#include <velodyne_pointcloud/point_types.h>
#include <pcl/common/common.h>
#include <pcl/common/centroid.h>
#include <pcl/common/transforms.h>
#include <pcl/console/parse.h>
#include <set>
#include <pcl/io/pcd_io.h>
#include <boost/format.hpp>
#include <pcl/point_types.h>
#include <pcl/io/pcd_io.h>
#include <pcl/filters/voxel_grid.h>
#include <pcl/filters/passthrough.h>

#include <pcl/sample_consensus/model_types.h>
#include <pcl/sample_consensus/method_types.h>
#include <pcl/segmentation/sac_segmentation.h>

struct VelodynePointXYZIRT
{
    PCL_ADD_POINT4D
    PCL_ADD_INTENSITY;
    uint16_t ring;
    float time;
    EIGEN_MAKE_ALIGNED_OPERATOR_NEW
} EIGEN_ALIGN16;
POINT_CLOUD_REGISTER_POINT_STRUCT (VelodynePointXYZIRT,
    (float, x, x) (float, y, y) (float, z, z) (float, intensity, intensity)
    (uint16_t, ring, ring) (float, time, time)
)

ros::Publisher pub1;

using PointXYZIRT = VelodynePointXYZIRT;

void help (const sensor_msgs::PointCloud2ConstPtr& scan)
{
    // Convert the sensor_msgs/PointCloud2 data to pcl/PointCloud
    pcl::PointCloud<VelodynePointXYZIRT>::Ptr cloud(new pcl::PointCloud<VelodynePointXYZIRT>());
    pcl::fromROSMsg (*scan, *cloud);

    pcl::ModelCoefficients coefficients;
    pcl::PointIndices inliers;
    // Create the segmentation object
    pcl::SACSegmentation< pcl::PointCloud<PointXYZIRT>> seg;

    // Optional
    seg.setOptimizeCoefficients (true);
    // Mandatory
    seg.setModelType (pcl::SACMODEL_PLANE);
    seg.setMethodType (pcl::SAC_RANSAC);
    seg.setDistanceThreshold (0.01);

    seg.setInputCloud (cloud.makeShared ());
    seg.segment (inliers, coefficients);

    // Publish the model coefficients
    pcl_msgs::ModelCoefficients ros_coefficients;
    pcl_conversions::fromPCL(coefficients, ros_coefficients);
    pub1.publish (ros_coefficients);
}

int main (int argc, char** argv)
{
    // Initialize ROS
    ros::init (argc, argv, "my_pcl_tutorial");
    ros::NodeHandle nh;

    // Create a ROS subscriber for the input point cloud
    ros::Subscriber sub = nh.subscribe ("input", 1, help);

    // Create a ROS publisher for the output point cloud
    //#pub1 = nh.advertise<sensor_msgs::PointCloud2> ("output", 1);
    pub1 = nh.advertise<pcl_msgs::ModelCoefficients> ("output", 1);

    // Spin
    ros::spin ();
}

as i have to put the ring data in the code, so i made the struct for defining the velodyne lidar, but when i catkin_make in the ros,

this error comes,

 error: ‘pcl::PointCloud<VelodynePointXYZIRT>::Ptr {aka class boost::shared_ptr<pcl::PointCloud<VelodynePointXYZIRT> >}’ has no member named ‘makeShared’
     seg.setInputCloud (cloud.makeShared ());

is there a method that i visualize the data?

my reference for making the code is this site,https://adioshun.gitbooks.io/pcl-tutorial/content/part-1/part01-chapter05/part01-chapter05-practice.html

and my previous code to transform the lidar data, i used these code to make my own.....

#include <iostream>
#include <cmath>
#include <vector>
#include <ros/ros.h>
#include <sensor_msgs/PointCloud2.h>
#include <pcl_ros/point_cloud.h>
#include <pcl/point_types.h>
#include <pcl_conversions/pcl_conversions.h>
#include <velodyne_pointcloud/point_types.h>
#include <pcl/common/common.h>
#include <pcl/common/centroid.h>
#include <pcl/common/transforms.h>
#include <pcl/console/parse.h>
#include <set>
#include <pcl/io/pcd_io.h>
#include <boost/format.hpp>
#include <pcl/point_types.h>
#include <pcl/io/pcd_io.h>
#include <pcl/filters/voxel_grid.h>
#include <pcl/filters/passthrough.h>

#define PI 3.14159265359

using namespace std;

struct VelodynePointXYZIRT
{
    PCL_ADD_POINT4D
    PCL_ADD_INTENSITY;
    uint16_t ring;
    float time;
    EIGEN_MAKE_ALIGNED_OPERATOR_NEW
} EIGEN_ALIGN16;
POINT_CLOUD_REGISTER_POINT_STRUCT (VelodynePointXYZIRT,
    (float, x, x) (float, y, y) (float, z, z) (float, intensity, intensity)
    (uint16_t, ring, ring) (float, time, time)
)

ros::Publisher pub1;

float theta_r =  45* M_PI/ 180; // 라디안 각도로 회전 (180도 회전)
using PointXYZIRT = VelodynePointXYZIRT;

void input(const sensor_msgs::PointCloud2ConstPtr& scan)
{

    // Msg to pointcloud
    pcl::PointCloud<VelodynePointXYZIRT>::Ptr cloud(new pcl::PointCloud<VelodynePointXYZIRT>());
    pcl::fromROSMsg(*scan,*cloud); // ros msg 에서 pcl cloud 데이터로 변환

    //회전변환행렬
    Eigen::Matrix4f transform_1 = Eigen::Matrix4f::Identity();
    // Define a rotation matrix (see https://en.wikipedia.org/wiki/Rotation_matrix)

    transform_1 (0,0) = std::cos (theta_r);
    transform_1 (0,2) = std::sin(theta_r);
    transform_1 (2,0) = -sin (theta_r);
    transform_1 (2,2) = std::cos (theta_r);

    
    //    (row, column)

    // Executing the transformation
    pcl::PointCloud<VelodynePointXYZIRT>::Ptr transformed_cloud (new pcl::PointCloud<PointXYZIRT>());
    pcl::transformPointCloud (*cloud, *transformed_cloud, transform_1);

    pcl::PCLPointCloud2 cloud_p;
    pcl::toPCLPointCloud2(*transformed_cloud, cloud_p); 

    sensor_msgs::PointCloud2 output;
    pcl_conversions::fromPCL(cloud_p, output);
    output.header.frame_id = "velodyne";
    pub1.publish(output);
}


int main(int argc, char** argv)
{
    ros::init(argc, argv, "input");
    ros::NodeHandle nh;
    ros::Subscriber sub = nh.subscribe<sensor_msgs::PointCloud2> ("vlp202", 100, input);
    pub1 = nh.advertise<sensor_msgs::PointCloud2> ("vlp203", 100);
    ros::spin();
}

//if you have to make your own type of custum point type in the pcl, you can see this one to see how to code it !!
// also the ring data that you have to use is from the lio_sam, image projection.cpp 

so for the abstract,

1. i want to remove floor point cloud data in recorded bag,
2. so i made some code to remove floor data

Answer 1

The "cloud" object is already a shared pointer. Remove makeShared call:

seg.setInputCloud (cloud.makeShared ());

to

seg.setInputCloud (cloud);

For visualization you could publish over a topic the result as ros message and visualize it with rviz.