I have trouble with Interpreter in Pycharm
Go to project interpreter settings in preferences in Pycharm, and use the + sign there to add the module to your interpreter. 
This can happen when pip is installing to a directory that is not part of your project's python interpreter's PATH.
Installing via the Pycharm preferences menu always solves for me, although there is a deeper issue of pip not installing to the correct directory...
I am python newbie. I am doing 1 project testing of Keras. I already installed opencv by pip install opencv-python but i can't find opencv in interpreter of Pycharm and have an error when i import cv2. My interpreter is usr/bin/python2.7