Hi,
Thanks for the nice idea,

When making the file I see that pcl_isfinite is not defined in the namespace, so when changing !pcl_isfinite (in_cloud->points[i].x) to !pcl::pcl_isfinite (in_cloud->points[i].x), this shows up:

make
Consolidate compiler generated dependencies of target pcl_norm_2d
[ 20%] Building CXX object CMakeFiles/pcl_norm_2d.dir/src/PCA2D.cpp.o
/PCL-Normal-Estimation-2d-master/src/PCA2D.cpp: In member function ‘void PCA2D::project(const ConstPtrCloud&, PtrCloud&)’:
/PCL-Normal-Estimation-2d-master/src/PCA2D.cpp:99:23: error: ‘pcl_isfinite’ is not a member of ‘pcl’; did you mean ‘isFinite’?
   99 |             if (!pcl::pcl_isfinite(in_cloud->points[i].x) ||
      |                       ^~~~~~~~~~~~
      |                       isFinite
/PCL-Normal-Estimation-2d-master/src/PCA2D.cpp:100:23: error: ‘pcl_isfinite’ is not a member of ‘pcl’; did you mean ‘isFinite’?
  100 |                 !pcl::pcl_isfinite(in_cloud->points[i].y) ||
      |                       ^~~~~~~~~~~~
      |                       isFinite
/PCL-Normal-Estimation-2d-master/src/PCA2D.cpp:101:23: error: ‘pcl_isfinite’ is not a member of ‘pcl’; did you mean ‘isFinite’?
  101 |                 !pcl::pcl_isfinite(in_cloud->points[i].z))
      |                       ^~~~~~~~~~~~
      |                       isFinite
make[2]: *** [CMakeFiles/pcl_norm_2d.dir/build.make:76: CMakeFiles/pcl_norm_2d.dir/src/PCA2D.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:111: CMakeFiles/pcl_norm_2d.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

and when I change pcl::pcl_isfinite() to !pcl::isFinite(in_cloud->points[i].x) I still see the following error:

make
Consolidate compiler generated dependencies of target pcl_norm_2d
[ 20%] Building CXX object CMakeFiles/pcl_norm_2d.dir/src/PCA2D.cpp.o
In file included from /usr/include/pcl-1.12/pcl/common/impl/centroid.hpp:45,
                 from /usr/include/pcl-1.12/pcl/common/centroid.h:1099,
                 from /PCL-Normal-Estimation-2d-master/src/../include/PCA2D.h:13,
                 from /PCL-Normal-Estimation-2d-master/src/PCA2D.cpp:5:
/usr/include/pcl-1.12/pcl/common/point_tests.h: In instantiation of ‘bool pcl::isFinite(const PointT&) [with PointT = float]’:
/PCL-Normal-Estimation-2d-master/src/PCA2D.cpp:99:31:   required from here
/usr/include/pcl-1.12/pcl/common/point_tests.h:57:31: error: request for member ‘x’ in ‘pt’, which is of non-class type ‘const float’
   57 |     return (std::isfinite (pt.x) && std::isfinite (pt.y) && std::isfinite (pt.z));
      |                            ~~~^
/usr/include/pcl-1.12/pcl/common/point_tests.h:57:55: error: request for member ‘y’ in ‘pt’, which is of non-class type ‘const float’
   57 |     return (std::isfinite (pt.x) && std::isfinite (pt.y) && std::isfinite (pt.z));
      |                                                    ~~~^
/usr/include/pcl-1.12/pcl/common/point_tests.h:57:79: error: request for member ‘z’ in ‘pt’, which is of non-class type ‘const float’
   57 |     return (std::isfinite (pt.x) && std::isfinite (pt.y) && std::isfinite (pt.z));
      |                                                                            ~~~^
make[2]: *** [CMakeFiles/pcl_norm_2d.dir/build.make:76: CMakeFiles/pcl_norm_2d.dir/src/PCA2D.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:111: CMakeFiles/pcl_norm_2d.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

What is the issue here? any hints?

In PCA source code, if indices isn't set, the computation will fail because automatic indices generation is missing. it is necessary that PCA2D and Normal 2D estimation inherit from PCLBase.

error: cannot convert ‘const IndicesPtr’ {aka ‘const boost::shared_ptr<std::vector<int, std::allocator > >’} to ‘const IndicesConstPtr&’ {aka ‘const std::shared_ptr<const std::vector<int, std::allocator > >&’}
60 | this->m_kd_tree->setInputCloud(m_in_cloud, m_indices);
| ^~~~~~~~~
| |
| const IndicesPtr {aka const boost::shared_ptr<std::vector<int, std::allocator > >}
In file included from /home/chenxiaocong/cvte_work/slam/code/PCL-Normal-Estimation-2d/src/../include/Normal2dEstimation.h:14,
from /home/chenxiaocong/cvte_work/slam/code/PCL-Normal-Estimation-2d/src/Normal2dEstimation.cpp:5:
/usr/local/include/pcl-1.12/pcl/search/search.h:121:47: note: initializing argument 2 of ‘void pcl::search::Search::setInputCloud(const PointCloudConstPtr&, const IndicesConstPtr&) [with PointT = pcl::PointXYZ; pcl::search::Search::PointCloudConstPtr = std::shared_ptr<const pcl::PointCloudpcl::PointXYZ >; pcl::search::Search::IndicesConstPtr = std::shared_ptr<const std::vector<int, std::allocator > >]’
121 | const IndicesConstPtr &indices = IndicesConstPtr ());
| ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/chenxiaocong/cvte_work/slam/code/PCL-Normal-Estimation-2d/src/Normal2dEstimation.cpp: In member function ‘void Normal2dEstimation::compute(const Ptr&) const’:
/home/chenxiaocong/cvte_work/slam/code/PCL-Normal-Estimation-2d/src/Normal2dEstimation.cpp:125:48: error: cannot convert ‘const IndicesPtr’ {aka ‘const boost::shared_ptr<std::vector<int, std::allocator > >’} to ‘const IndicesConstPtr&’ {aka ‘const std::shared_ptr<const std::vector<int, std::allocator > >&’}
125 | this->m_kd_tree->setInputCloud(m_in_cloud, m_indices);
| ^~~~~~~~~
| |
| const IndicesPtr {aka const boost::shared_ptr<std::vector<int, std::allocator > >}
In file included from /home/chenxiaocong/cvte_work/slam/code/PCL-Normal-Estimation-2d/src/../include/Normal2dEstimation.h:14,
from /home/chenxiaocong/cvte_work/slam/code/PCL-Normal-Estimation-2d/src/Normal2dEstimation.cpp:5:
/usr/local/include/pcl-1.12/pcl/search/search.h:121:47: note: initializing argument 2 of ‘void pcl::search::Search::setInputCloud(const PointCloudConstPtr&, const IndicesConstPtr&) [with PointT = pcl::PointXYZ; pcl::search::Search::PointCloudConstPtr = std::shared_ptr<const pcl::PointCloudpcl::PointXYZ >; pcl::search::Search::IndicesConstPtr = std::shared_ptr<const std::vector<int, std::allocator > >]’
121 | const IndicesConstPtr &indices = IndicesConstPtr ());
| ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/chenxiaocong/cvte_work/slam/code/PCL-Normal-Estimation-2d/src/Normal2dEstimation.cpp: In member function ‘bool Normal2dEstimation::computePointNormal2d(boost::shared_ptr<std::vector<int, std::allocator > >&, Eigen::Vector3f&) const’:
/home/chenxiaocong/cvte_work/slam/code/PCL-Normal-Estimation-2d/src/Normal2dEstimation.cpp:268:27: error: no matching function for call to ‘pcl::PCApcl::PointXYZ::setIndices(boost::shared_ptr<std::vector<int, std::allocator > >&)’
268 | pca.setIndices(indices);

Hi, I have been using this repo for a while now with the fork I have created. This was very useful to me and I have used this in my ms thesis. I have understood how you computed the normals by finding the eigenvectors of the alpha matrix but, I would like to refer to this method by its 'scientific name' if there is any. I am planning to cite this repo and the method that you are using. I would like to know if there is any 'scientific term' for calculating normals this way.

Thanks in advance,
Ulaş

Just thought I'd note for anyone else who comes across this, with PCL 1.12, C++14, changing all the boost references etc, it works but only in Debug mode (I think - CMake default). Changing to release mode (-DCMAKE_BUILD_TYPE=Release) causes the algorithm to fail.