Lens distortion correction method based on linear approximation

Aiming at the influence of lens distortion to imaging measurement system, this paper puts forward an improved method for lens distortion correction based on linear approximation. Firstly, the method solves the radial distortion coefficient linearly based on the principle of cross-ratio invariance under perspective projection. Then a higher precision of the straight line is obtained according to the orthogonal distance fitting. Finally, a comprehensive distortion index function is built to get the distortion coefficient via Gauss-Newton method. Simulation results show that the average correcting error of this method is less than 0.2 pixel, in the case of 800 control points and 0.1 noise standard deviation. With the characteristic of easy to implement, strong robustness and high precision, the method proposed in this paper is suitable for high precision correction in machine vision.