方法有2：

    1. 使用源代码CMake编译
    2. 使用低版本opencv模块

    本文主要记录方法2。
    3.4.2.16是最后一个支持nonfree模块的opencv库

    1. 卸载旧版本opencv

      1. pip uninstall opencv-python
      2. pip uninstall opencv-contrib-python

    2. opencv 3.4.2.16版本最多支持到python 3.6版本，需要创建虚拟环境

      1. conda install nb_conda
      2. conda create -n opencvnonfree python=3.6
      3. conda activate opencvnonfree

    3. 安装所需的库 ```powershell pip install numpy pip install pandas pip install setuptools pip install —ignore-installed six pip install python-dateutil pip install jupyter

    conda install imutils conda install scikit-image conda install —upgrade jupyterthemes

    ref: https://blog.csdn.net/qq_26870933/article/details/88211711 https://blog.csdn.net/qq_30565883/article/details/79444750 https://www.zhihu.com/question/40012144

    2. 4. 安装opencv库
    3. ```powershell
    4. pip install opencv-python==3.4.2.16
    5. pip install opencv-contrib-python==3.4.2.16
    7. ref:
    8. https://blog.csdn.net/cliukai/article/details/102525486
    1. 打开jupyter notebook

    opencv使用nonfree模块 - 图1

    附上方法1的链接：
    https://opencv.org/releases/#
    https://sourceforge.net/projects/opencvlibrary/
    https://pypi.org/project/opencv-contrib-python/#files
    https://xugaoxiang.com/2019/12/18/windows-10-cuda-cudnn/