ros catkin_make fails opencv

i had the same problem (jetson xavier + ubuntu 18.04 + ros melodic)

we fixed it like this:

change the file:

/opt/ros/melodic/share/cv_bridge/cmake/cv_bridgeConfig.cmake
change this line:

set(_include_dirs "include;/usr/include;/usr/include/opencv")
to

set(_include_dirs "include;/usr/include;/usr/include/opencv4")

运行时报如下错误：
from cv_bridge.boost.cv_bridge_boost import cvtColorForDisplay, getCvType
SystemError: initialization of cv_bridge_boost raised unreported exception

原因：导入顺序出错。

解决方案：
from cv_bridge import CvBridge # ROS与OpenCV图像转换类
import cv2 # Opencv图像处理库

修改成如下顺序：
import cv2 # Opencv图像处理库
from cv_bridge import CvBridge # ROS与OpenCV图像转换类

catkin_make

catkin_make install  

install/lib/..../a.py