warning: libopencv_imgproc.so.4.2, needed by /opt/ros/noetic/lib/libcv_bridge.so, may conflict with libopencv_imgproc.so.4.5 vision_opencv
参考：
https://answers.ros.org/question/360288/how-to-resolve-opencv-multiple-ver-conflicts-while-building-orb-slam2/
下载https://github.com/ros-perception/vision_opencv中的noetic版本的最新版。放到src中，catkin_make编译后，就可以了。不要卸载原有的。
