第一个窗口运行 roslaunch vins_estimator euroc.launch 可能会报以下错误：

[feature_tracker-1] process has died [pid 3807, exit code -11, cmd /home/yaowei/catkin_ws/devel/lib/feature_tracker/feature_tracker __name:=feature_tracker __log:=/home/yaowei/.ros/log/f758c002-c23b-11ed-9f4b-e127444f3b2a/feature_tracker-1.log].
log file: /home/yaowei/.ros/log/f758c002-c23b-11ed-9f4b-e127444f3b2a/feature_tracker-1*.log

BRIEF_PATTERN_FILE/home/yaowei/catkin_ws/src/VINS-Mono-master/pose_graph/../support_files/brief_pattern.yml

[pose_graph-3] process has died [pid 3809, exit code -11, cmd /home/yaowei/catkin_ws/devel/lib/pose_graph/pose_graph __name:=pose_graph __log:=/home/yaowei/.ros/log/f758c002-c23b-11ed-9f4b-e127444f3b2a/pose_graph-3.log].
log file: /home/yaowei/.ros/log/f758c002-c23b-11ed-9f4b-e127444f3b2a/pose_graph-3*.log

将catkin_ws/src/VINS_Mono目录下的所有子文件夹的CMakeLists.txt中的find_package(OpenCV REQUIRED)全部改成find_package(OpenCV 4)，然后再从新catkin_make,又会出现第七章第一步的错误，解决方法和之前一样。