CALIBRATION OF CAMERA PARAMETERS USING VANISHING POINTS

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.