Opencv camera calibration in cpp

Oltre che con uno script Python come visto qui la calibrazione della camera si puo' fare anche con il programma in CPP

Questo il procedimento per compilare il programma partendo dai sorgenti

 

git clone https://github.com/opencv/opencv

git clone https://github.com/opencv/opencv_contrib

 

sudo cmake -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D OPENCV_ENABLE_NONFREE=ON \
-D INSTALL_C_EXAMPLES=ON \
-D INSTALL_PYTHON_EXAMPLES=ON \
-D OPENCV_GENERATE_PKGCONFIG=ON \
-D OPENCV_PC_FILE_NAME=opencv.pc \
-D OPENCV_GENERATE_PKCONFIG=ON \
-D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib/modules \
-D PYTHON_EXECUTABLE=/usr/bin/python3 \
-D PYTHON_DEFAULT_EXECUTABLE=$(which python3) .. \
-D BUILD_EXAMPLES=ON  \
-D BUILD_opencv_apps=ON  \
-DBUILD_opencv_gapi:BOOL=OFF
-D BUILD_DOCS=ON \
..

 

sudo make install 

export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:/usr/local/lib

 

si naviga fino al folder

/opencv/samples/cpp/tutorial_code/calib3d/camera_calibration 

e si digita il comando

g++ -ggdb camera_calibration.cpp -o camera_calibration `pkg-config --cflags --libs opencv`

per il funzionamento del programma occorrono due file xml, il primo con le impostazioni ed il secondo con l'elenco delle immagini di calibrazione

camera_calibration -d parametri.xml

parametri.xml

<?xml version="1.0"?>

<opencv_storage>

<Settings>

<!-- Number of inner corners per a item row and column. (square, circle) -->

<BoardSize_Width>9</BoardSize_Width>

<BoardSize_Height>4</BoardSize_Height>

<!-- The size of a square in some user defined metric system (pixel, millimeter)-->

<Square_Size>0.115</Square_Size>

<Marker_Size>0.090</Marker_Size>

<!-- The type of input used for camera calibration. One of: CHESSBOARD CHARUCOBOARD CIRCLES_GRID ASYMMETRIC_CIRCLES_GRID -->

<Calibrate_Pattern>"CHARUCOBOARD"</Calibrate_Pattern>

<ArUco_Dict_Name>DICT_4X4_250</ArUco_Dict_Name>

<ArUco_Dict_File_Name></ArUco_Dict_File_Name>

<!-- The input to use for calibration.

To use an input camera -> give the ID of the camera, like "1"

To use an input video -> give the path of the input video, like "/tmp/x.avi"

To use an image list -> give the path to the XML or YAML file containing the list of the images, like "/tmp/circles_list.xml"

-->

<Input>"elenco_foto.xml"</Input>

<!-- If true (non-zero) we flip the input images around the horizontal axis.-->

<Input_FlipAroundHorizontalAxis>0</Input_FlipAroundHorizontalAxis>

<!-- Time delay between frames in case of camera. -->

<Input_Delay>100</Input_Delay>

<!-- How many frames to use, for calibration. -->

<Calibrate_NrOfFrameToUse>25</Calibrate_NrOfFrameToUse>

<!-- Consider only fy as a free parameter, the ratio fx/fy stays the same as in the input cameraMatrix.

Use or not setting. 0 - False Non-Zero - True-->

<Calibrate_FixAspectRatio> 1 </Calibrate_FixAspectRatio>

<!-- If true (non-zero) tangential distortion coefficients are set to zeros and stay zero.-->

<Calibrate_AssumeZeroTangentialDistortion>1</Calibrate_AssumeZeroTangentialDistortion>

<!-- If true (non-zero) the principal point is not changed during the global optimization.-->

<Calibrate_FixPrincipalPointAtTheCenter> 1 </Calibrate_FixPrincipalPointAtTheCenter>

<!-- The name of the output log file. -->

<Write_outputFileName>"parametri_camera.xml"</Write_outputFileName>

<!-- If true (non-zero) we write to the output file the feature points.-->

<Write_DetectedFeaturePoints>1</Write_DetectedFeaturePoints>

<!-- If true (non-zero) we write to the output file the extrinsic camera parameters.-->

<Write_extrinsicParameters>1</Write_extrinsicParameters>

<!-- If true (non-zero) we write to the output file the refined 3D target grid points.-->

<Write_gridPoints>1</Write_gridPoints>

<!-- If true (non-zero) we show after calibration the undistorted images.-->

<Show_UndistortedImage>1</Show_UndistortedImage>

<!-- If true (non-zero) will be used fisheye camera model.-->

<Calibrate_UseFisheyeModel>0</Calibrate_UseFisheyeModel>

<!-- If true (non-zero) distortion coefficient k1 will be equals to zero.-->

<Fix_K1>0</Fix_K1>

<!-- If true (non-zero) distortion coefficient k2 will be equals to zero.-->

<Fix_K2>0</Fix_K2>

<!-- If true (non-zero) distortion coefficient k3 will be equals to zero.-->

<Fix_K3>0</Fix_K3>

<!-- If true (non-zero) distortion coefficient k4 will be equals to zero.-->

<Fix_K4>1</Fix_K4>

<!-- If true (non-zero) distortion coefficient k5 will be equals to zero.-->

<Fix_K5>1</Fix_K5>

</Settings>

</opencv_storage>

elenco_foto.xml

<?xml version="1.0"?>

<opencv_storage>

<images>

hikvision/01.jpg

hikvision/02.jpg

hikvision/03.jpg

hikvision/04.jpg

hikvision/05.jpg

hikvision/06.jpg

hikvision/07.jpg

hikvision/08.jpg

hikvision/09.jpg

hikvision/10.jpg

hikvision/11.jpg

hikvision/12.jpg

hikvision/13.jpg

hikvision/14.jpg

hikvision/15.jpg

hikvision/16.jpg

</images>

</opencv_storage>