A pinhole camera projects a point from the 3-D projective space onto a point of the 2-D projective plane. This projection can be written as a homogeneous matrix of rank equal to 3 :

where is the equality up to a scale factor. If we restrict the 3-D projective space to the Euclidean space, then it is well known that can be written as :

and are the rotation and translation that link the camera frame to the 3-D Euclidean one. The most general form for the matrix of intrinsic parameters is :

where is the horizontal scale factor, **k** is the ratio between the vertical and horizontal scale factors, **r** is the image skew and and are the image coordinates of the center of projection.

Mon Dec 7 13:48:06 GMT 1998