c++ 为什么pcl::PointNormal RANSAC圆柱体模型声明在估计模型系数时不包含法线?

iqxoj9l9  于 2023-01-22  发布在  其他
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我一直在尝试使用pcl工具将圆柱体模型拟合到生成的点云上,我一直在修改here文档中提供的示例代码。
据我所知,pcl::SampleConsensusModelCylinder需要法线数据,所以我在代码中添加了一个新的检查,用于检查-cf参数。然后,代码计算pcl::Normals类型点云中每个点的法线(称为cloud_normals),并将其与原始pcl::PointXYZ类型点云连接。我将其保存到称为cloud_normalpoints的新的pcl::PointNormal类型的点云,并且利用该点云,我尝试使用随机采样一致性(RANSAC)来拟合pcl::SampleConsensusModelCylinder
我已经包含了下面的代码:

else if (pcl::console::find_argument (argc, argv, "-cf") >= 0 )
  {
    //TODO: find fastest way to fit cylinder model to point cloud
    // the cloud_normals point cloud will be used to store the point cloud or normals
    pcl::PointCloud<pcl::Normal>::Ptr cloud_normals (new pcl::PointCloud<pcl::Normal>);
    cloud_normals->width    = 500;
    cloud_normals->height   = 1;
    // is_dense is True if no points have NaN or Inf in any of their floating points field
    cloud_normals->is_dense = false;
    cloud_normals->points.resize (cloud_normals->width * cloud_normals->height);

    // the NormalEstimation object ne is created and will estimate the normals and curvature at each point
    pcl::NormalEstimation<pcl::PointXYZ, pcl::Normal> ne;
    // the search:KdTree object pointer points to a search method for finding points in 3D space (3D point clouds)
    pcl::search::KdTree<pcl::PointXYZ>::Ptr tree (new pcl::search::KdTree<pcl::PointXYZ> ());
    // use the filtered cloud as an input to the normal estimator
    ne.setInputCloud (cloud);
    // set number of k-nearest neighbours to use for feature estimation to 50
    ne.setKSearch (50);
    // compute normals and save these to the clouds_normals point cloud
    ne.compute (*cloud_normals);

    pcl::PointCloud<pcl::PointNormal>::Ptr cloud_normalpoints (new pcl::PointCloud<pcl::PointNormal>);
    cloud_normalpoints->width    = 500;
    cloud_normalpoints->height   = 1;
    // is_dense is True if no points have NaN or Inf in any of their floating points field
    cloud_normalpoints->is_dense = false;
    cloud_normalpoints->points.resize (cloud_normalpoints->width * cloud_normalpoints->height);

    pcl::concatenateFields(*cloud,*cloud_normals,*cloud_normalpoints);

    //TODO: Solve normals not given error
    pcl::SampleConsensusModelCylinder<pcl::PointNormal, pcl::Normal>::Ptr
      model_c (new pcl::SampleConsensusModelCylinder<pcl::PointNormal, pcl::Normal> (cloud_normalpoints));
    // Declares ransac as a ransac implementation searching for a cylinder (according to model_c -> in cloud)
    pcl::RandomSampleConsensus<pcl::PointNormal> ransac (model_c);
    // Set distance threshold of .01 -> believe this is for inliers
    ransac.setDistanceThreshold (.01);
    // Compute model coefficients and find inliers
    ransac.computeModel();
    
    // Return indices of best set of inliers so far for this model
    ransac.getInliers(inliers);
  }

我还添加了一些代码来生成一个包含圆柱体的原始点云,但这是可行的,所以我不会在这里详细介绍。
当我运行我的代码时,它进入计算模型阶段,然后抛出以下错误:
[pcl::SampleConsensusModelCylinder::computeModelCoefficients] No input dataset containing normals was given!
有人知道这是为什么吗?cloud_normalpoints云包括了每个点的正常数据。我应该设置不同的RANSAC估计器吗?我应该使用不同的点类型吗?我对pcl比较陌生,所以任何帮助都将不胜感激!

rryofs0p

rryofs0p1#

你必须调用model_c的函数setInputNormals,在这里你传递了cloud_normals,你在SampleConsensusModelCylinder的构造函数中传递的云只设置XYZ信息,而不用于法线。
本教程也可能对您感兴趣:https://pcl.readthedocs.io/projects/tutorials/en/latest/cylinder_segmentation.html

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