Linewise Non-Rigid Registration (LNRR)

This repository provides a basic implementation of the non-rigid point cloud registration method described in [1]. For a detailed explanation of the method and its motivation, please refer to the original paper. In a nutshell, the method is able to find the set of rigid transformations that need to be applied to each line in the scan in order to match an existing model:

You can also watch the video that summarizes this work:

Thank you for citing the original publication [1] if you use our method in academic work:

@ARTICLE{9788023,  
  author={Castillón, Miguel and Ridao, Pere and Siegwart, Roland and Cadena, César},
  journal={IEEE Robotics and Automation Letters},
  title={Linewise Non-Rigid Point Cloud Registration},
  year={2022},
  volume={7},
  number={3},
  pages={7044-7051},
  doi={10.1109/LRA.2022.3180038}}

If you want to know more about our underwater 3D scanner, check out the paper [2] and this blog post.

Publications

[1] M. Castillón, P. Ridao, R. Siegwart and C. Cadena, "Linewise Non-Rigid Point Cloud Registration," in IEEE Robotics and Automation Letters, doi: 10.1109/LRA.2022.3180038. [pdf]

[2] M. Castillón, J. Forest and P. Ridao, "Underwater 3D Scanner to Counteract Refraction: Calibration and Experimental Results," in IEEE/ASME Transactions on Mechatronics, doi: 10.1109/TMECH.2022.3170504. [pdf]

Installation

Dependencies

Our methods depends on CMake, Eigen, and Ceres. Please note that so far, it has only been tested on Ubuntu 20.04 + Eigen 3.3.7 + Ceres 2.0.

Moreover, our method uses Fast Gauss Transforms to compute the correspondence probability between each pair of points. Therefore, our method depends on fgt, which is a fork of this repository.

Compilation

As usual, just download and unzip this repository in your preferred location and cd into it. Then:

mkdir build
cd build
cmake ..
make
sudo make install

If you want Debug messages to be printed for each iteration, compile using

cmake -DCMAKE_BUILD_TYPE=Debug ..

Usage

#include <lnrr/scan_to_model.h>

int main(int argc, char** argv) {
    lnrr::Matrix fixed = loadModel();
    lnrr::Matrix moving = loadScan();
    lnrr::Vector line_sizes;  // Vector containing the number of points in each line
    double beta = ...;
    double lambda = ...;

    lnrr::ScanToModel lnrr(fixed, moving, beta, lambda, line_sizes);
    lnrr::Result result = lnrr.run();
    return 0;
}

And your CMakeLists.txt should include:

find_package(OpenMP REQUIRED)
find_package(Ceres REQUIRED)
find_package(Fgt REQUIRED)
find_package(Lnrr REQUIRED)

add_library(my-new-library
    my_program.cpp
    )
target_link_libraries(my-new-library
    PUBLIC
    Lnrr::Library-C++
    ${CERES_LIBRARIES}
    )

Contributing

Please feel free to create issues and pull requests, they will be much appreciated.

Documentation

Please be aware that this repository is only a simple implementation of the method and may therefore unfortunately not always show a robust behaviour. There is no documentation yet but we hope the code is self-explanatory.

License

In the creation of this library we have drawn inspiration from this cpd implementation by Gadomski.

neu-yuezhang / lnrr