ros中如何使用自带的opencv库- opencv undefined reference problem

参考链接https://answers.ros.org/question/57187/opencv-undefined-reference-problem/
　　　　https://blog.youkuaiyun.com/lixujie666/article/details/89183941
ROS自带的opencv版本为3.0，我们可以在实际的项目中使用，但是，如果链接库忘了写，或者写错了，会出现
opencv undefined reference problem的问题，参考上面的链接，我们可以这样写CMakelist.txt

第一种方法

set(OpenCV_DIR /opt/ros/kinetic/share/OpenCV-3.3.1-dev/)
find_package(catkin REQUIRED COMPONENTS
  OpenCV
)

第二种方法

Add to your CMakeLists.txt:

find_package( OpenCV REQUIRED )

include_directories( ${OpenCV_INCLUDE_DIRS} )

and link your targets against OpenCV_LIBS:

target_link_libraries( your_target ${OpenCV_LIBS} )