本代码是Tsai两步法标定程序，针对平面靶标实现摄像机标定-This code is a two-step calibration procedures Tsai for planar camera calibration targets to achieve

通过很多摄像机坐标系下的点，拟合平面方程，摄像机坐标系下可以得到一条直线方程，光刀平面和靶标平面相交线上每一点的世界坐标(By using the points in many camera coordinate systems to fit the plane equations, a linear equation can be obtained under the camera coordinate system, and the world coordinates of each poi

在第一条直线上可以得到多个点，在第二条直线上也可以得到多个点，因此就可以得到再用一束线激光投射到棋盘格的相纸靶标上，重复上面的方法，便可以得到第三个交点（xc3，yc3，zc3），把这三个点代入光刀平面方程(Multiple points can be obtained on the first straight line, and multiple points can also be obtained on the second straight line. Therefore, a las