安装opencv-3.4.0后和ros自带的3.2.0版本冲突，导致open_vins、vins-mono、vins-fusion均无法编译成功

使用ros自带的opencv3.2.0时vins系列的代码都可以正常跑通，因为项目需要opencv3.4.0，安装后出现编译错误

参考：

https://blog.csdn.net/weixin_40749043/article/details/127547954

重要 https://blog.csdn.net/llllldm/article/details/126334841

（一）ros-melodic-cv-bridge和opencv3.4.0冲突（vins-mono vins-fusion问题解决，open-vins部分解决）

解决办法（首先确保其他版本的opencv是否卸载干净！）

然后

1 更改 gedit /opt/ros/melodic/share/cv_bridge/cmake/cv_bridgeConfig.cmake

# yzl 2023.2.19 modified
# if(NOT "include;/usr/include;/usr/include/opencv " STREQUAL " ")
if(NOT "include;/usr/local/include/opencv;/usr/local/include/opencv2 " STREQUAL " ")
  set(cv_bridge_INCLUDE_DIRS "")
  #set(_include_dirs "include;/usr/include;/usr/include/opencv")
  set(_include_dirs "include;/usr/local/lib;/usr/local/include/opencv;/usr/local/include/opencv2;/usr/local/include;")
  set(libraries "cv_bridge;/usr/local/lib/libopencv_core.so.3.4.0;/usr/local/lib/libopencv_imgproc.so.3.4.0;/usr/local/lib/libopencv_imgcodecs.so.3.4.0")

以及

# yzl 2023.2.19 modified
#set(libraries "cv_bridge;/usr/lib/x86_64-linux-gnu/libopencv_core.so.3.2.0;/usr/lib/x86_64-linux-gnu/libopencv_imgproc.so.3.2.0;/usr/lib/x86_64-linux-gnu/libopencv_imgcodecs.so.3.2.0")
set(libraries "cv_bridge;/usr/local/lib/libopencv_core.so.3.4.0;/usr/local/lib/libopencv_imgproc.so.3.4.0;/usr/local/lib/libopencv_imgcodecs.so.3.4.0")

2 更改/opt/ros/melodic/share/cv_bridge/cmake/cv_bridge-extras.cmake

# yzl 2023.2.19 modifed
#set(OpenCV_VERSION 3.2.0)
#set(OpenCV_VERSION_MAJOR 3)
#set(OpenCV_VERSION_MINOR 2)
#set(OpenCV_VERSION_PATCH 0)
set(OpenCV_VERSION 3.4.0)
set(OpenCV_VERSION_MAJOR 3)
set(OpenCV_VERSION_MINOR 4)
set(OpenCV_VERSION_PATCH 5)

**3 更改sudo gedit /opt/ros/melodic/lib/pkgconfig/cv_bridge.pc **

# yzl 2023.2.29 modified
#Libs: -L${prefix}/lib -lcv_bridge /usr/lib/x86_64-linux-gnu/libopencv_core.so.3.2.0 /usr/lib/x86_64-linux-gnu/libopencv_imgproc.so.3.2.0 /usr/lib/x86_64-linux-gnu/libopencv_imgcodecs.so.3.2.0
Libs: -L${prefix}/lib -lcv_bridge /usr/local/lib/libopencv_core.so.3.4.0 /usr/local/lib/libopencv_imgproc.so.3.4.0 /usr/local/lib/libopencv_imgcodecs.so.3.4.0

通过上述修改后没有报错，但是有如下warnning

在[/home/yzl/Learn_SLAM/vins-fusion_ws/devel/lib]

ldd libvins_lib.so | grep opencv

有三个库链接错

执行

cd /opt/ros/melodic/lib/
ldd libcv_bridge.so | grep opencv

尝试

sudo apt-get install --reinstall ros-melodic-desktop-full

然后重新按照上面的步骤来，就没有warning了

到这里vins-mono和vins-fusion都没有问题了，但是openvins报错了

（二）open-vins缺少opencv-contrib-3.4.0中的库（open-vins问题解决）

aruco.hpp好像是额外的库

https://stackoverflow.com/questions/33200173/opencv-3-0-error-aruco-hpp-no-such-file-or-directory

locate没有

下载opencv_contrib-3.4.0到opencv-3.4.0同文件夹

然后

cmake .. -D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib-3.4.0/modules/        

报错了：

gflags的问题，重新编译gflags

cd build/
cmake -DCMAKE_CXX_FLAGS=-fPIC ..
make
sudo make  install
sudo ldconfig

成功，感动。。。

然后

sudo make install

后catkin build

open_vins编译成功