Affine Constrained Binocular Camera Calibration With Planar Target Single-Axis Translating

Binocular camera is widely used in high-accuracy 3-D measurement and the systematic error is critically determined by the calibration of camera parameters. This article proposes a binocular camera calibration method based on planar target with different orientations translating along single axis. The translation of planar target composes a calibration grid, which is localized in an affine coordinate system (ACS). In addition, nonhomogeneous projection equations of binocular camera indicate the relationship between ACS and image projection coordinate system (IPCS). Therefore, a linear estimation of binocular camera parameters is obtained. In addition, we collect multiple calibration grids with different orientations to improve the estimation accuracy of principal points. Finally, we minimize reprojection error to optimize these camera parameters. Simulation and application experiments demonstrate that our method achieves less focal length error (0.063 pixel) than traditional calibration method using arbitrary placed planar target (0.123 pixel), and less principal point error (0.220 pixel) than pure translation method (0.271 pixel).