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Creating mesh from a simple point cloud

asked 2014-08-17 15:56:08 -0500

aknirala gravatar image

updated 2014-08-17 15:59:12 -0500

Hi,

I am trying to create mesh from a point cloud, and currently having trouble finding the right parameters/methods to get good result. I have created point cloud (sampled from a, plane extracted from, kinect scan) in a structured way where the points are in a grid.

When I generate a mesh using pcl::GreedyProjectionTriangulation, I see that points are beng used just once, and hence the mesh I am getting is simply set of triangels all separated. Please see the two pics, pointCloud:

and Mesh (I want a mesh where there are no gaps. I can easily create a ply format file for this since this is a plane, but it would be difficult to create it for complex point clouds. I am sure there already is a method to do so.

, where mesh is being displayed in meshlab (I convereted vtk to ply by using a custom code).

Please let me know what parameters to use.

My i/p point cloud have two points separated by 0.025 meters. The parameter for mesh are: (I am not able to see any difference on changing these)

p_setKSearch: 20
p_setSearchRadius: 0.1
p_setMu: 5
p_neighbours: 100
p_maxSurfAnglePiDiv: 4
p_minAnglePiDiv: 18
p_maxAnglePiDiv: 1.5
p_normal_consist: true

The code I am using to convertPointCLoud to Mehs is:

void CreateWorld::createMeshFromCloud(pcl::PointCloud<pointrgb>::Ptr &ipCloudI){

//Let's first convert it to PointXYZ
pcl::PointCloud<pointType>::Ptr cloud = getXYZfromRGB(ipCloudI); //pointType is pointXYZ

pcl::NormalEstimation<pointType, pcl::Normal> n;
pcl::PointCloud<pcl::Normal>::Ptr normals (new pcl::PointCloud<pcl::Normal>);

pcl::search::KdTree<pcl::PointXYZ>::Ptr tree (new pcl::search::KdTree<pcl::PointXYZ>);
tree->setInputCloud (cloud);
n.setInputCloud (cloud);
n.setSearchMethod (tree);
n.setKSearch (ParamValue::p_setKSearch);        //It was 20
n.compute (*normals);                //Normals are estimated using standard method.


// Concatenate the XYZ and normal fields*
pcl::PointCloud<pcl::PointNormal>::Ptr cloud_with_normals (new pcl::PointCloud<pcl::PointNormal>);
pcl::concatenateFields (*cloud, *normals, *cloud_with_normals);
//* cloud_with_normals = cloud + normals

// Create search tree*
pcl::search::KdTree<pcl::PointNormal>::Ptr tree2 (new pcl::search::KdTree<pcl::PointNormal>);
tree2->setInputCloud (cloud_with_normals);

// Initialize objects
pcl::GreedyProjectionTriangulation<pcl::PointNormal> gp3;
pcl::PolygonMesh triangles;

// Set the maximum distance between connected points (maximum edge length)
gp3.setSearchRadius (ParamValue::p_setSearchRadius);            //It was 0.025

// Set typical values for the parameters
gp3.setMu (ParamValue::p_setMu);                                            //It was 2.5
gp3.setMaximumNearestNeighbors (ParamValue::p_neighbours);    //It was 100
gp3.setMaximumSurfaceAngle(M_PI/ParamValue::p_maxSurfAnglePiDiv); // 45 degrees    //it was 4
gp3.setMinimumAngle(M_PI/ParamValue::p_minAnglePiDiv); // 10 degrees        //It was 18
gp3.setMaximumAngle(M_PI/ParamValue::p_maxAnglePiDiv); // 120 degrees        //it was 1.5
gp3.setNormalConsistency(ParamValue::p_normal_consist);                    //It was false

// Get result
gp3.setInputCloud (cloud_with_normals);
gp3.setSearchMethod (tree2);
gp3.reconstruct (triangles);

// Additional vertex information
std::vector<int> parts = gp3.getPartIDs();
std::vector<int> states = gp3.getPointStates();
//pcl::io::
pcl::io::saveVTKFile (ParamValue::planeMeshVTK, triangles);

std::cout<<"\n\n\t Calling conversion from VTK to PLY";
convertVtkToPly(ParamValue::planeMeshVTK, ParamValue::planeMeshPLY);

}

Any help/pointer is greatly appreciated.

Thanks

Nirala A K

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answered 2014-08-27 06:19:48 -0500

Airuno2L gravatar image

You'll be able to get help on this much faster if you post it to the PCL mailing list. Luckily it is very active.

Also, if you don't need to do this programmatically, creating the mesh in MeshLab instead of PCL would be much easier. Here and here are some tutorials on how to do that.

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Thanks Arinuo, I did posted there http://www.pcl-users.org/Creating-mesh-from-a-simple-point-cloud-td4035178.html got no reply.
It would be good if I could get this done via code. I am going through the tutorial you pointed though.

aknirala gravatar imageaknirala ( 2014-08-29 13:04:33 -0500 )edit

Thanks Arinuo,

aknirala gravatar imageaknirala ( 2014-08-29 13:04:34 -0500 )edit
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Asked: 2014-08-17 15:56:08 -0500

Seen: 6,180 times

Last updated: Aug 27 '14