How do I convert a mesh to a pointcloud for use with pcl ICP

asked 2012-05-12 10:06:20 -0600

brawner
581 ●4 ●14 ●15

updated 2012-05-13 08:45:28 -0600

I want to find partial overlaps between meshes in the household object database and pointcloud sensor data. My method is to convert the arm_navigation_msgs::Shape to a pcl::PointCloud and then find clusters that overlap through pcl::IterativeClosestPoint. I have all pieces working, I just think my function for converting the shape meshes to pointclouds is inefficient. Is there a way to take advantage of the underlying structure to speed up the conversion?

This is my current implementation

pcl::PointCloud<pcl::PointXYZ> PCLMeshOverlap::convertMeshToPointcloud(arm_navigation_msgs::Shape mesh)
{
    ROS_INFO("Converting mesh to pointcloud");
    pcl::PointCloud<pcl::PointXYZ> cloud_out;
    pcl::PointXYZ point;
    for (int i = 0; i < mesh.vertices.size(); i++)
    {
        float isNew = true;
        for (int j = 0; j < cloud_out.points.size(); j++)
        {
            if (    mesh.vertices.at(i).x == cloud_out.points.at(j).x &&
                    mesh.vertices.at(i).y == cloud_out.points.at(j).y &&
                    mesh.vertices.at(i).z == cloud_out.points.at(j).z   )
            {
                isNew = false;
                break;
            }
        }
        if (isNew)
        {
            point.x = mesh.vertices.at(i).x;
            point.y = mesh.vertices.at(i).y;
            point.z = mesh.vertices.at(i).z;
            cloud_out.points.push_back(point);
        }
    }
    cloud_out.width = cloud_out.points.size();
    cloud_out.height = 1;
    cloud_out.is_dense = true;
    cloud_out.header.frame_id = "/base_link";
    return cloud_out;
}

*Edited because the original code had some typos

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1

answered 2013-12-18 19:01:25 -0600

isura

403 ●5 ●11 ●15

updated 2014-05-29 09:55:21 -0600

Asomerville
2743 ●74 ●99 ●133 http://www.resquared.com/

You could do this in ROS Hydro PCL 1.7 if your mesh was a pcl::PolygonMesh:

#include <pcl io="" vtk_lib_io.h="">

const std::string meshFileName = "test.stl";

pcl::PolygonMesh testMesh;
pcl::io::loadPolygonFileSTL( meshFileName, testMesh );    
pcl_conversions::fromPCL( testMesh.cloud, output );

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Does this conversion sample points on the surfaces or strictly converts the vertices in the STL file into points in the point cloud? If not, is there any tool out that does sample points on the surfaces?

ben ( 2014-02-03 16:09:57 -0600 )edit

@ben to my knowledge this just converts vertices in the STL file into points in the point cloud. I am not aware of a tool that resamples points. Did you find any good solution?