I\'ve been trying to install both OpenCV and cv2 from both Pycharm and from the terminal as suggested using:
pip install --user opencv pip install --user cv2
How about try some different mirrors? If you are in China, I highly recommend you try:
sudo pip install --index https://pypi.mirrors.ustc.edu.cn/simple/ opencv-contrib-python
If not, just replace the url address to some other mirrors you like! Good luck.