Flexible and Accurate Camera Calibration Using Imperfect Planar Target

摘要

Camera calibration using a 2D planar board is widely applied because of the flexibility and simplicity of this method. However, this technique fails to yield reliable and accurate calibration results when an imperfect planar target is used. The accuracy of the image and world coordinates for the extracted corners, which are prerequisites for deriving precise camera parameters, are affected by the lens distortion and the non-planarity of the calibration target. In this paper, the accuracy of the obtained image coordinates is improved by combining a Hilbert transform with a traditional calibration method. In addition, the geometry of the calibration target is fully considered so as to acquire precise world coordinates using an overall nonlinear parameter optimization algorithm. The reprojection error of the proposed method is reduced by 80% compared with the traditional method for a significantly deformed planar target, which demonstrates the superiority of the proposed camera-calibration technique.