（总结）（2）编译ORB_SLAM2遇到的错误
问题一：/usr/include/pcl-1.10/pcl/point_types.h:698:1: error: ‘plus’ is not a member of ‘pcl::traits’
698 | POINT_CLOUD_REGISTER_POINT_STRUCT (pcl::_PointDEM,
解决办法：在CMakeLists.txt里增加
set(CMAKE_CXX_STANDARD 14)问题二：error: ‘plusscalar’ is not a member of ‘pcl::traits’
698 | POINT_CLOUD_REGISTER_POINT_STRUCT (pcl::_PointDEM,
解决办法：找到CMakeLists.txt文件，加入
set(CMAKE_CXX_STANDARD 14)问题三：error: ‘CV_RGB2GRAY’ was not declared in this scope
177 | cvtColor(mImGray,mImGray,CV_RGB2GRAY);
解决办法：在头文件里添加 #include <opencv2/imgproc/types_c.h>
问题四：error: ‘CvMat’ does not name a type
102 | void find_betas_approx_1(const CvMat * L_6x10, const CvMat * Rho, double * betas);
解决办法：添加头文件
#include <opencv2/core/types_c.h>