出現這種錯誤OpenCV3.0 和 4.0 都是一樣的，不是版本導致的問題，不要在版本中掙紮啦！

最省心最安全最簡潔的方式就是下載Anaconda+OpenCV再安裝，別用單獨的Python了...Python的Python和Anaconda的Python還是有一點點不一樣...況且你都用OpenCV做項目了，那不得更加換成Anaconda了嗎...

（2）Anaconda4.5.11安裝OpenCV4.0.0

• 查看當前Anaconda的版本和包含的Python解釋器的版本：

D:\DevKits\Anaconda3\Scripts>conda info

     active environment : None
       user config file : C:\Users\Seven\.condarc
 populated config files : C:\Users\Seven\.condarc
          conda version : 4.5.11
    conda-build version : 3.15.1
         python version : 3.7.0.final.0
       base environment : D:\DevKits\Anaconda3  (writable)
           channel URLs : https://conda.anaconda.org/conda-forge/win-64
                          https://conda.anaconda.org/conda-forge/noarch
                          https://repo.anaconda.com/pkgs/main/win-64
                          https://repo.anaconda.com/pkgs/main/noarch
                          https://repo.anaconda.com/pkgs/free/win-64
                          https://repo.anaconda.com/pkgs/free/noarch
                          https://repo.anaconda.com/pkgs/r/win-64
                          https://repo.anaconda.com/pkgs/r/noarch
                          https://repo.anaconda.com/pkgs/pro/win-64
                          https://repo.anaconda.com/pkgs/pro/noarch
                          https://repo.anaconda.com/pkgs/msys2/win-64
                          https://repo.anaconda.com/pkgs/msys2/noarch
          package cache : D:\DevKits\Anaconda3\pkgs
                          C:\Users\Seven\AppData\Local\conda\conda\pkgs
       envs directories : D:\DevKits\Anaconda3\envs
                          C:\Users\Seven\AppData\Local\conda\conda\envs
                          C:\Users\Seven\.conda\envs
               platform : win-64
             # 由此可知Ananconda的版本是4.5.11, Python的版本的3.7.0
             user-agent : conda/4.5.11 requests/2.19.1 CPython/3.7.0 Windows/10 Windows/10.0.17763
          administrator : False
             netrc file : None
           offline mode : False
 

• 下載地址：https://www.lfd.uci.edu/~gohlke/pythonlibs

• 下載如下文件：

# OpenCV的核心包
opencv_python?4.0.0?cp37?cp37m?win_amd64.whl
# OpenCV的核心包+擴展包
opencv_python?4.0.0+contrib?cp37?cp37m?win_amd64.whl

• 離線安裝：

D:\DevKits\Anaconda3\Scripts>pip.exe install C:\Users\Seven\Downloads\opencv_python-4.0.0+contrib-cp37-cp37m-win_amd64.whl
Processing c:\users\seven\downloads\opencv_python-4.0.0+contrib-cp37-cp37m-win_amd64.whl
Installing collected packages: opencv-python
    Successfully uninstalled opencv-python-4.0.0
Successfully installed opencv-python-4.0.0+contrib
 

• 測試安裝：

>>> import cv2
>>> cv2.__version__
‘4.0.0‘

（3）解決完成後

（4）問題原因

無論是OpenCV3還是OpenCV4，都遇到了同樣的問題...當你是用pip安裝OpenCV的時候，在PyCharm或VisualStudio中可能不會有代碼提示...需要在線安裝是可以的，但是步驟麻煩...我就沒寫...在線安裝時pip將OpenCV安裝到了Lib/site-packages/cv2中了，而使用離線安裝的方式直接安裝到Lib/site-packages中，那麽：如果采用的在線安裝有兩種解決方案：

方案一：

在cv2目錄中，打開__init__.py

sys.modules[‘cv2‘] = cv2

方案二：

導包時使用這樣的方式：

from cv2 import cv2 as cv

• Tips: 如果不是Anaconda安裝的Python，Python會在Lib目錄查找.

Anaconda安裝OpenCV沒有自動代碼補全