It looks like this problem is caused by ROS adding /opt/ros/kinetic/lib/python2.7/dist-packages
to the python path. This actually happens when you activate ROS with the command source /opt/ros/kinetic/setup.bash
. This line is often added at the end of your bashrc file, in /home/username/.bashrc
.
A workaround is to remove this line from the bashrc file. This way the python3 opencv packages will be correctly used, and you can still run source /opt/ros/kinetic/setup.bash
to use ROS. However, this does mean you cannot use ROS and python3 from the same environment.
Hopefully someone can come up with a better answer, but this should work until then.