What are the camera parameter calibration methods?

World coordinate system;

Camera coordinate system;

Image coordinate system;

Generally speaking, the calibration process is divided into two parts:

The first step is the transformation from the world coordinate system to the camera coordinate system, which is the transformation from three-dimensional points to three-dimensional points, including RR, tt (off-camera reference) and other parameters;

The second part is the transformation from camera coordinate system to image coordinate system, which is the transformation from three-dimensional point to two-dimensional point, including KK (camera internal reference) and other parameters; CC represents the center of the camera, that is, the center of the camera and the center of the camera coordinate system;

The ZZ axis represents the main axis, which is the main axis of the camera;

The plane where the pp point is located represents the image plane, that is, the image plane of the camera, that is, the two-dimensional plane where the picture coordinate system is located;

The Pp point represents the principal point, that is, the point where the principal axis intersects the image plane;

The distance from CC point to pp point, that is, ff stands for focal length in the right picture, that is, the focal length of the camera;

The xx axis and yy axis on the image plane are parallel to each other in the camera coordinate system;

The camera coordinate system consists of three axes: XX, YY and ZZ (the capital), the origin is at CC point, and the measured value is m;

The image plane coordinate system consists of two axes, xx and yy (lowercase), the origin is at pp point, and the measured value is meters (m);