Magnetic calibration

C++ package for magnetic calibration

Autors :

🧑‍🏫 Thomas LE MEZO [email protected] (ENSTA Bretagne, Lab-STICC)

🧑‍🏫 Maël GODARD [email protected] (ENSTA Bretagne, Lab-STICC)

Git Structure :

• 📁 /dataset : folder containing the input datasets
• 📁 /include : folder containing header files
• 📁 /src : folder containing source files
• 🗒️ CMakeLists.txt CMakeLists to compile
• 🗒️ package.xml
• 🗒️ README.md

Technologies :

• C++
• Eigen
• Vtk 9.0
• CMake

Building the package for the first time

• Clone the repository :

# for ssh clone
git clone [email protected]:godardma/magnetic_calibration.git
# for https clone
git clone https://github.com/godardma/magnetic_calibration.git

• Open a terminal in the created folder
• Setup the build folder :

mkdir build && cd build && cmake ..

Launching :

From a terminal in the build folder :

make && ./mag_calibration

Using the package

An exemple main file can be found here

The main steps are :

• Create an instance of the object MagneticCalibration

• Fill the field "magnetometer_data_regularized_" :

  • Use the function "generate_data" to use the the default dataset, no need to regularize it
  • Fill the field "magnetometer_data_" by hand and regularize the dataset
  • Fill the field "magnetometer_data_" from a file using the function "create_data_from_file" and regularize the dataset

  The regularization is done by calling the function "regularize_data", arguments are the limit of point in a box and its limit size

• Perform the ellipsoid fit with the "compute_ellipsoid" function to get its center and the transformation matrix (noted TR) between the ellipsoid and a sphere

Other useful functions provided are :

• correct_data: Applies the correction to "magnetometer_data_" and stores the result in "magnetometer_data_corrected_"
• check_correction: Performs an ellipsoid fit on "magnetometer_data_corrected_" to check if it matches a sphere as it should
• view_data: to visualize the data, arguments are point size and the range of the displayed axis
  • In black the raw data, stored magnetometer_data_
  • In red the regularized data, stored magnetometer_data_regularized
  • In green the corrected data, stored magnetometer_data_corrected, and the corresponding sphere

Notes for users

The package seems to struggle to perform a proper calibration when big values are passed as inputs. We highly suggest to keep the values in the range [-1000,1000] by scaling your inputs if necessary to get a proper result.

License :

This package is under GNU General Public License

Credits :

The credits belong to Thomas LE MEZO (ENSTA Bretagne, Lab-STICC) and Maël GODARD (ENSTA Bretagne Lab-STICC)