参考https://docs.opencv.org/4.1.0/d5/de5/tutorial_py_setup_in_windows.html
方法一：到官网上https://www.python.org/downloads/windows/，下载对应的installer，双击即可
缺点：
Problem is that, there is no official 64-bit binaries of Numpy.
You have to build it on your own. For that, you have to use the same compiler used to build Python.
When you start Python IDLE, it shows the compiler details. You can get more information here.
So your system must have the same Visual Studio version and build Numpy from source.
方法二：直接安装anaconda(https://www.anaconda.com/distribution/).
Anaconda指的是一个开源的Python发行版本，其包含了conda、Python等180多个科学包及其依赖项.