Calibration with ball objects for telecentric micro-vision system

The calibration of the micro-vision system is an fundamental issue in the micro-vision based measurement and control areas. The calibration methods for conventional macro-vision system are not suitable for telecentric micro-vision system. This paper proposes a calibration method with ball objects for the telecentric micro-vision system, which is used for the 3-dimensional relative pose measurement. The ball objects are low-cost and easy to be made. The intrinsic parameters and depth of field of camera are calibrated with a one-ball object. The angle between the camera's optical axis and the linear stage's axis is considered, and the image offset matrix caused by this angle is calibrated using the one-ball object. Furthermore, the image Jacobian matrices of two cameras are obtained by calibrating the two cameras' rotation transformation using a two-ball object. The experimental results verify the calibration methods' effectiveness and accuracy.