A new technique for calibrating the intrinsic and extrinsic parameters
of a video imaging system, based on vanishing points is presented. Th
e intrinsic parameters of the camera refers to the focal length of the
lens, the physical dimensions of each pixel and the exact position of
the optical center on the image grid, as well as the radial distortio
n of the lens. The extrinsic parameters refer to the position and orie
ntation of the camera described in a predefined frame of reference cal
led the world coordinate system. The proposed method requires only one
view of a specially designed test object, or two distinct views of a
solid cube. Other objects rich in parallel lines can be used as well.
Two views must be generated by subjecting the object to an arbitary co
mposite three-dimensional (3D) displacement within the field of view o
f the camera. It is not required to know the exact 3D motion parameter
s; however, it is necessary to know the initial position and orientati
on of the cube with respect to the world coordinate system. An intrins
ic parameter that is often not addressed is the radial distortion fact
or. It remains fixed for each lens and thus has been considered a part
of the lens specification. The camera model used in this paper incorp
orates the radial distortion factor; however, the basic equations beco
me highly nonlinear (eighth order). Two cameras connected to the same
digitizer hardware have been calibrated to experimentally verify and i
llustrate the feasibility of the proposed new technique.