I tried installing OpenCV on Windows 10 using pip. I used this command- pip install opencv-contrib-python
After that when I tried importing cv2 on command prompt, it
You have installed openCV in Python running on your Terminal, not into the working environment which Jupyter Notebooks is running from.
Whilst in Terminal write:
py -m pip install opencv-python
When you use pip list
pip list
You should see opencv-python 3.4.3.18
opencv-python 3.4.3.18
More information here.