A New Camera Calibration Method Based on Two Vertical Lines

This paper presents a new method to estimate the internal parameters of a camera based on two vertical lines. It does not require any actual size of calibration object and does not use the homograph matrix. In this method, we firstly use two vertical lines whose lengths can be any size, and then mark their intersection, endpoints, and midpoints in the image. And then our algorithm finds the subpixel coordinates of these points and makes the equations according to their vertical relationship. At last, all internal parameters can be obtained by solving the equations. Zhang's method is now the most popular calibration method. After obtaining the actual length of the checkerboard, he calculates the internal parameters of the camera by estimating the homograph matrix. In our method, the estimation of the homograph matrix is not needed, and the error caused by the estimation is avoided, so it is not necessary to measure the actual size of the checkerboard, which makes the calibration simpler.