Visualize pointcloud

Question

I have 3D points from gpu::reprojectImageTo3D on a found disparity image. I would now like to display this pointcloud.

How do I Convert the found pointcloud from OpenCV to sensor_msgs/PointCloud2 ?

I do not need to publish the pointcloud this is only for debug visualization. Could it be possible to display it as is done with images from the node? e.g. using pcl? This would be optimal since my device may not perform well with RViz (based on readings online).

Answer 1

My best guess is to do like this, and just iterate through the cv::mat and insert in the pcl to convert to msg, since I have not found anything that does directly.

#include <ros/ros.h>
// point cloud headers
#include <pcl/point_cloud.h>
//Header which contain PCL to ROS and ROS to PCL conversion functions
#include <pcl_conversions/pcl_conversions.h>
//sensor_msgs header for point cloud2
#include <sensor_msgs/PointCloud2.h>
main (int argc, char **argv)
{
    ros::init (argc, argv, "pcl_create");
    ROS_INFO("Started PCL publishing node");
    ros::NodeHandle nh;
    //Creating publisher object for point cloud
    ros::Publisher pcl_pub = nh.advertise<sensor_msgs::PointCloud2> ("pcl_output", 1);
    //Creating a cloud object
    pcl::PointCloud<pcl::PointXYZ> cloud;
    //Creating a sensor_msg of point cloud
    sensor_msgs::PointCloud2 output;
    //Insert cloud data
    cloud.width  = 50000;
    cloud.height = 2;
    cloud.points.resize(cloud.width * cloud.height);
    //Insert random points on the clouds
    for (size_t i = 0; i < cloud.points.size (); ++i)
    {
        cloud.points[i].x = 512 * rand () / (RAND_MAX + 1.0f);
        cloud.points[i].y = 512 * rand () / (RAND_MAX + 1.0f);
        cloud.points[i].z = 512 * rand () / (RAND_MAX + 1.0f);
    }
    //Convert the cloud to ROS message
    pcl::toROSMsg(cloud, output);
    output.header.frame_id = "point_cloud";
    ros::Rate loop_rate(1);
    while (ros::ok())
    {
        //publishing point cloud data
        pcl_pub.publish(output);
        ros::spinOnce();
        loop_rate.sleep();
    }
    return 0;
}

This code snippet was found at apprize.