Abstract: Machine calibration is a very important step in the work of visual measurement. The camera calibration method proposed by professor Zhang Zhengyou is one of the most widely used methods at present. But Zhang's method only considers the radial distortion of the first two steps, so this paper studies the influence of the high order radial distortion on the accuracy of the calibration method. We take the board grid as the simulation template, carry on the simulation calibration experiment based on Matlab, obtain the error of the calibration result under different radial distortion conditions, and analyze the relationship between them. In this paper, the relationship between the three order radial distortion and the calibration error and the curve of the relationship between the four order radial distortion and the calibration error are drawn. The influence of three order radial distortion and four order radial distortion on the calibration error is very similar. The curve of the high order radial distortion and the calibration error curve are basically in line with the parabola. At the same time, the influence of the higher order radial distortion on the calibration accuracy of the two order radial coefficient is much larger than that of the calibration precision of the first order radial coefficient.

Key words: radial distortion, camera calibration, Zhang's calibration method