Hi all,
Thank you Martins for recommendations.
I answer my own question for those who are interested by the topic:
You can create in few lines a 3D viewer on which you can add point clouds and shapes :
Please refer to the official tutorials for details http://pointclouds.org/documentation/tutorials/pcl_visualizer.php
/* generic 3D viewer display, similar to the official tutorials.
changes added : camera setup :
_ use the viewer->resetCameraViewpoint("Considered blobs"); to point to the middle of your point cloud
_ use viewer->setCameraPosition (cameraPoxitionX, cameraPoxitionY, cameraPoxitionZ, viewX, viewY, viewZ) // to set the camera position and its directions
*/
Consider the following includes... first check your system configuration (add pcl library and dependencies),
#include <pcl/common/common_headers.h>
#include <pcl/point_cloud.h>
#include <pcl/impl/point_types.hpp>>
#include <pcl/io/pcd_io.h>
#include <pcl/visualization/pcl_visualizer.h>
#include <boost/thread/thread.hpp>
// This method display 3D COLOURED points
boost::shared_ptr<pcl::visualization::PCLVisualizer> createVisualizer (pcl::PointCloud<pcl::PointXYZRGB>::ConstPtr cloud)
{
boost::shared_ptr<pcl::visualization::PCLVisualizer> viewer (new pcl::visualization::PCLVisualizer ("3D Viewer"));
viewer->setBackgroundColor (0, 0, 0);
pcl::visualization::PointCloudColorHandlerRGBField<pcl::PointXYZRGB> rgb(cloud);
viewer->addPointCloud<pcl::PointXYZRGB> (cloud, rgb, "myPoints");
viewer->setPointCloudRenderingProperties (pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 3, "myPoints");
viewer->addCoordinateSystem ( 1.0 );
viewer->initCameraParameters ();
viewer->resetCameraViewpoint("myPoints"); // camera points to the center of the point cloud
viewer->setCameraPosition ( camXPos, camXPos, camXPos, // camera position
0, 1, 0 // camera direction to cloud center
); // ... then camera faces the point cloud
return (viewer);
}
Once prepared and considering a cv::Mat image "colorImage" and a binary mask "areas" , add points to your point cloud and display it :
... take care of X&Y inversions (take into account the top left (0,0) of cv::Mat reference points)
...HINT, the Z axis can be used as the temporal information like in this exemple (time is refered as "frameIndex" here
Allocate your point cloud :
pcl::PointCloud<pcl::PointXYZRGB>::ConstPtr point_cloud_ptr(new pcl::PointCloud<pcl::PointXYZRGB>);
Fill the point cloud with the localizes and coloured segmented blob points
for(int y=0;y<colorImage.rows;++y)
for(int x=0;x<colorImage.cols;++x)
{
// get pixel data
cv::Scalar maskPoint = areas.at<unsigned char>(cv::Point2d(x,y));
cv::Vec3b colorPoint = colorImage.at<cv::Vec3b>(cv::Point2d(x,y));
if (maskPoint[0])
{
//std::cout<<"New point (x,y,z) = "<<x<<", "<<y<<", "<<frameIndex
// <<" // (r,g,b) = "<<(int)pr<<", "<<(int)pg<<", "<<(int)pb<<std::endl;
//Insert info into point cloud structure
pcl::PointXYZRGB point;
point.x = -x;
point.y = -y;
point.z = frameIndex;
uint32_t rgb = (static_cast<uint32_t>(colorPoint.val[2]) << 16 |
static_cast<uint32_t>(colorPoint.val[1]) << 8 | static_cast<uint32_t>(colorPoint.val[0]));
point.rgb = *reinterpret_cast<float*>(&rgb);
point_cloud_ptr->points.push_back (point);
}
}
Finally, when the cloud is ready, display it by calling the first procedure :
... check doc to add any supplementary shape, here, a cude is added (dims are image size*timeLength).
std::cout<<"Pointcould size : "<<point_cloud_ptr->points.size()<<std::endl;
boost::shared_ptr<pcl::visualization::PCLVisualizer> viewer = createVisualizer( point_cloud_ptr );
viewer->addCube (-colorImage.cols, 0, -colorImage.rows, 0, 0, timeLength);
//Main user ...
(more)
