Catadioptric Camera Calibration with One-Dimensional Objects
Deng Xiao · Chinese Journal of Computers · 2007
A 1-D calibration object is meant a segment with several known-distance markers(or points).Generally speaking,calibration methods with 1D objects are more flexible than those with 2D or 3D objects.Under the pinhole camera model,Zhang[9] proved that the calibration is not possible with free-moving 1D objects,but can be done if one of the markers is fixed.In this paper,the authors propose a catadioptric camera calibration method using 1D objects with five or more known points.The method is capable of calibrating a camera when either the camera or the calibration object undertakes three or more general motions.The proposed algorithm consists of the following two steps: Firstly,the principal point is calculated with geometric invariants under catadioptric camera model;Secondly,for every image point of 1D object,a pair of orthogonal vanishing points is derived,by which the image of absolute conic(IAC) is computed,then the intrinsic parameter matrix is obtained by Cholesky factorization on the IAC.In addition,the analytical solutions of the mirror parameter and the 1D object′s pose are also provided.In simulated experiments,the method can have good calibration even if the fitting of partial visible conic is not very accurate.In the real experiment,the correctness and feasibility of the proposed method is also confirmed.