Circle detection and line detection of PCL

One 、 Circle detection

// Search all circles , Know that no eligible circle can be found , Record the center and radius of the circle 
    int index=0;
    while(1)
    {
    
        pcl::visualization::PCLVisualizer viewer2("Visualization of original and target point cloud");
        viewer2.setBackgroundColor(255,255,255);

        pcl::PointCloud<pcl::PointXYZ>::Ptr Circle2D(new pcl::PointCloud<pcl::PointXYZ>);
        pcl::PointCloud<pcl::PointXYZ>::Ptr tempRemain(new pcl::PointCloud<pcl::PointXYZ>);

        pcl::SampleConsensusModelCircle2D<pcl::PointXYZ>::Ptr model_circle2D(new pcl::SampleConsensusModelCircle2D<pcl::PointXYZ>(Src_Cloud_Planar));
        std::vector<int> inliers;

        pcl::RandomSampleConsensus<pcl::PointXYZ> ransac(model_circle2D);
        ransac.setDistanceThreshold(0.001);
        ransac.computeModel();
        ransac.getInliers(inliers);
        qDebug()<<" Number of point clouds ："<<inliers.size();
        // If you can't find a circle , sign out 
        if(inliers.size()==0)
        {
    
            break;
        }

        pcl::IndicesPtr tempinliers(new std::vector<int>(inliers));
        Eigen::VectorXf modelParas;
        ransac.getModelCoefficients(modelParas);
        std::cout << modelParas<< "\n\n";
        qDebug()<<modelParas(0);
        qDebug()<<modelParas(1);
        qDebug()<<modelParas(2);
        qDebug()<<"002!";

        // Get points and delete points 2D
        pcl::ExtractIndices<pcl::PointXYZ> Circle_extract;
        Circle_extract.setInputCloud(Src_Cloud_Planar);// Enter the point cloud 
        Circle_extract.setIndices(tempinliers);
        Circle_extract.setNegative(false);
        Circle_extract.filter(*Circle2D);//line2D Split this time 2D Line --
        // Delete point 
        Circle_extract.setNegative(true);
        Circle_extract.filter(*tempRemain);
        *Src_Cloud_Planar = *tempRemain;// The remaining point clouds this time --

        // If you can't find a circle , sign out 
        if(inliers.size()<=60)
        {
    
            viewer2.close();
            continue;
        }

        // Draw a circle 
        QVector<pcl::PointXYZ> points;
        double o_x = modelParas(0), o_y=modelParas(1), r = modelParas(2);    // Center and radius of circle 
        for (int i = 0; i < 100; i++)   // Calculate the coordinates of points on the ring 
        {
    
            pcl::PointXYZ point;
            double alpha = 2 * M_PI / (100 - 1);
            point.x = o_x + r * cos(i * alpha);
            point.y = o_y + r * sin(i * alpha);
            point.z = 0;
            points.push_back(point);
        }
        // Connect the points on the ring with line segments 
        for (int i = 0; i < points.size() - 1; i++)
        {
    
            viewer2.addLine(points.at(i), points.at(i + 1), QString("CircleLineX%1").arg(index).toStdString(), 0);
            index=index+1;
        }
        viewer2.addLine(points.at(points.size() - 1), points.at(0), QString("CircleLineX%1_%2").arg(points.size()).arg(5).toStdString(), 0);
        index=index+1;
        //------------------- Visualization of original point cloud and filtered target point cloud ------------------------
        pcl::visualization::PointCloudColorHandlerCustom<pcl::PointXYZ> single_color(Src_Cloud_Planar, 0, 255, 0);
        viewer2.addPointCloud<pcl::PointXYZ>(Src_Cloud_Planar, single_color, "Source clouds");
        while (!viewer2.wasStopped())
        {
    
            viewer2.spinOnce(1);
        }
    }
    qDebug()<<"003!";
    while (!viewer00.wasStopped())
    {
    
        viewer00.spinOnce(1);
    }

Two 、 Straight line detection

//  Straight line is obtained through filtering （ After deleting , Just cycle many times ）
    pcl::PointCloud<pcl::PointXYZ>::Ptr line2D(new pcl::PointCloud<pcl::PointXYZ>);
    pcl::PointCloud<pcl::PointXYZ>::Ptr cloud_f2D(new pcl::PointCloud<pcl::PointXYZ>);
    pcl::PointCloud<pcl::PointXYZ>::Ptr ptCloud2D(new pcl::PointCloud<pcl::PointXYZ>);

    // Create a model parameter object , Used to record results 
    pcl::ModelCoefficients::Ptr coefficients3(new pcl::ModelCoefficients);
    //inliers Indicates the point where the error can be tolerated   Record the serial number of the point cloud 
    pcl::PointIndices::Ptr inliers3(new pcl::PointIndices);
    //  Create a splitter 
    pcl::SACSegmentation<pcl::PointXYZ> seg;
    // Optional
    seg.setOptimizeCoefficients(true);
    // Mandatory- Set the target geometry 
    seg.setModelType(pcl::SACMODEL_LINE);//SACMODEL_LINE SACMODEL_PLANE notes ： Modify the model name here 
    // Segmentation method ： Random sampling 
    seg.setMethodType(pcl::SAC_RANSAC);//SAC_RANSAC
    // The maximum number of iterations 
    seg.setMaxIterations(100);
    // Set the error tolerance range 
    seg.setDistanceThreshold(0.0005);// notes ： Fill in the specific value 
    // Enter the point cloud 
    seg.setInputCloud(Tgt_Cloud_Planar);// Enter the point cloud 
    // Split point cloud 
    seg.segment(*inliers3, *coefficients3);

    // Get points and delete points 2D
    pcl::ExtractIndices<pcl::PointXYZ> extract2;
    extract2.setInputCloud(Tgt_Cloud_Planar);// Enter the point cloud 
    extract2.setIndices(inliers3);
    extract2.setNegative(false);
    extract2.filter(*line2D);//line2D Split this time 2D Line --
    // Delete point （ notes ： If you recognize multiple lines , Then delete the identified power line point cloud , Then the cycle ）
    extract2.setNegative(true);
    extract2.filter(*cloud_f2D);
    *ptCloud2D = *cloud_f2D;//ptCloud2D The remaining point clouds this time --

    pcl::visualization::PointCloudColorHandlerCustom<pcl::PointXYZ> single_color3(line2D, 0, 0, 0);
    viewer00.addPointCloud<pcl::PointXYZ>(line2D, single_color3, "Target clouds90");
    // Connect the points on the line with line segments 
    for (int i = 0; i < line2D->size() - 1; i++)
    {
    
        viewer00.addLine(line2D->points[i], line2D->points[i+1], QString("LineX%1").arg(i).toStdString(), 0);
    }
    viewer00.addLine(line2D->points[line2D->size() - 1], line2D->points[0], QString("LineX%1_%2").arg(line2D->size()).arg(5).toStdString(), 0);

    qDebug()<<"size"<<line2D->size();
    qDebug()<<"003!";
    while (!viewer00.wasStopped())
    {
    
        viewer00.spinOnce(1);
    }