说明： 直接法把路标点和机器人位姿同时作为优化变量，最小化重投影误差构建做小二乘模型没利用高斯牛顿求解 (The direct method uses the landmark points and the robot pose as optimization variables at the same time, minimizes the reprojection error, and constructs a small square model without using Gaussian Newton.)
