Robust calibration method for microscopic vision systems

Abstract

In order to improve the stability of the calibration method based on a single parallel plane, we propose a robust calibration method based on the calculation of traditional homography matrix and Gaussian imaging model. This method first uses a convenient and accurate method to calculate the physical focal length of the entire microscope optical system, and then uses the Gaussian imaging model to calculate the effective focal length and intrinsic matrix of the camera. Then, the camera’s extrinsic parameters can be easily calculated from the homography matrix. Finally, all camera parameters can be optimized along with the lens distortion through a nonlinear optimization process. In this method, only two images of the parallel calibration plate need to be captured to complete the calibration. The proposed method overcomes the problem of instability of the existing microscope calibration methods and significantly improves the robustness and accuracy of the whole calibration process.