Camera calibration estimates the parameters relating points in a scene to measured image coordinates. In the ideal pinhole model,where contains focal lengths and the principal point, while the rotation matrix and translation locate the camera relative to the scene. Lens distortion requires additional parameters.[ref]
Camera Calibration and 3D Reconstruction by OpenCV. Detailed Description, pinhole model and distortion coefficients
A calibration experiment photographs a flat board with a known grid from several orientations. Detected grid corners provide image measurements; their known spacing supplies geometric constraints and a length scale. Parameters are fitted by minimizing reprojection error. Multiple orientations help separate camera geometry from board pose. For an ideal camera with focal length 1000 pixels, a point displaced sideways at depth projects 50 pixels from the principal point.[ref]
Camera Calibration and 3D Reconstruction by OpenCV. calibrateCamera, planar-pattern initialization and reprojection error
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