Camera calibration with ArUco

To perform camera calibration as we discussed earlier, we must obtain corresponding 2D-3D point pairings. With ArUco marker detection, this task is made simple. ArUco provides a tool to create a calibration board, a grid of squares and AR markers, in which all the parameters are known: number, size, and position of markers. We can print such a board with our home or office printer, with the image for printing supplied by the ArUco API: 

Ptr<aruco::Dictionary> dict = aruco::Dictionary::get(aruco::DICT_ARUCO_ORIGINAL);
Ptr<aruco::GridBoard> board = aruco::GridBoard::create(
    10     /* N markers x */, 
    7      /* M markers y */, 
    14.0f  /* marker width (mm) */, 
    9.2f   /* marker separation (mm) */, 
    dict);
Mat boardImage;
board->draw({1000, 700}, boardImage, 25); // an image of 1000x700 pixels
cv::imwrite("ArucoBoard.png", boardImage);

Here is an example of such a board image, a result of the preceding code:

We need to obtain multiple...