常见解决办法

错误一：you are using pip version ** howerver version ** is available.
you should consider upgrading via the ‘python -m pip install --upgrade pip’ command.
键入 'python -m pip install --upgrade pip’依旧出错
解决办法：在命令窗口运行pip install opencv-python 后重试

错误二：Could not find a version that satisfies the requirement openCV (from versions: ) No matching distribution found for openCV；Traceback (most recent call last): File “”, line 1, in Module
解决办法：
因为最新python在pip库没有匹配的版本，所以使用pip安装会报错
Could not find a version that satisfies the requirement opencv (from versions: )
No matching distribution found for opencv
因此，到这儿去下载opencv
http://www.lfd.uci.edu/~gohlke/pythonlibs/
选择opencv_python-4.0.1-cp37-cp37m-win_amd64.whl
拷贝opencv_python-4.0.1-cp357cp37m-win_amd64.whl到Python安装目录下的Lib\site-packages
在D:\Program Files\Python\Lib\site-packages目录下允许命令安装
pip install opencv_python-4.0.1-cp37-cp357-win_amd64.whl
在python下运行 import cv2 不报错就是安装成功了

官方下载网址汇总:
python下载:https://www.python.org/downloads/windows/
opencv-python下载：https://www.lfd.uci.edu/~gohlke/pythonlibs/#opencv

工具包下载

要下载的有numpy,pillow,scipy,matplotlib这些，都可以通过pip直接完成，前提是pip已经更新到最新版本。
安装过程中出现pip install scipy但是安装不了的情况，后来通过改变语句为
pip install --user scipy解决，matplotlib也同理
另外下载过程要确保网络顺畅，否则也容易出现预计要几个小时的情况，一般每个工具包包最多几分钟就可以了