Install OpenCV under window7

• http://www.lfd.uci.edu/~gohlke/pythonlibs/  Find the corresponding version of openCV, you can Ctrl+F to find opencv.
• opencv_python-3.3.0-cp36-cp36m-win_amd64.whl represents openCV 3.3.0 version, python3.6 version, windows 64-bit, find the version that suits you.
• To be safe, install the Visual C++ 2015 redistribution package, https://www.microsoft.com/en-us/download/details.aspx?id=48145
• Switch to the opencv_python-3.3.0-cp36-cp36m-win_amd64.whl directory and open the terminal, pip install opencv_python-3.3.0-cp36-cp36m-win_amd64.whl