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Calibration of camera parameters using vanishing points

Journal of the Franklin Institute
Publication Date
DOI: 10.1016/0016-0032(94)90037-x
  • Design


Abstract A new technique for calibrating the intrinsic and extrinsic parameters of a video imaging system, based on vanishing points is presented. The 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 distortion of the lens. The extrinsic parameters refer to the position and orientation of the camera described in a predefined frame of reference called 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. The two views must be generated by subjecting the object to an arbitrary composite three-dimensional ( 3D) displacement within the field of view of the camera. It is not required to know the exact 3D motion parameters; however, it is necessary to know the initial position and orientation of the cube with respect to the world coordinate system. An intrinsic parameter that is often not addressed is the radial distortion factor. It remains fixed for each lens and thus has been considered a part of the lens specification. The camera model used in this paper incorporates the radial distortion factor; however, the basic equations become highly nonlinear (eighth order). Two cameras connected to the same digitizer hardware have been calibrated to experimentally verify and illustrate the feasibility of the proposed new technique.

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