Camera Calibration

where W = [W1,W2,W3] is a world point in the world reference frame, X = [X1, X2, X3] is W reexpressed in the camera’s reference frame, x = [x1, x2] is the projection of X in the canonical camera reference frame, ξ = [ξ1, ξ2] is x re-expressed in the image reference frame. The vector π = [π1, π2] is the principal point in image coordinates, f is the camera’s focal distance, and the diagonal elements of the matrix S̃ = [ s̃1 0 0 s̃2 ]