How to install OpenCV for Python 3.x on Windows 8.1?

Question

I am trying to install and run OpenCV 3.0.0 for python 3.4.2, in Windows 8.1.

1. I have downloaded the OpenCV file from http://opencv.org/.
2. Extracted the folder in C:.
3. I went to System → Advanced System Settings → Advanced → Environment variables
4. Add a new variable in "User Variables frame". Name it "OPENCV_DIR" with value "c:\opencv\build\x64\vc12".
5. Add this at the end of Path: ";C:\opencv;C:\opencv\build;%OPENCV_DIR%\bin"
6. I took the archive "cv2.pyd" from "C:\opencv\build\python\2.7\x64" and copied it.
7. I pasted it in C:\Python34\Lib\site-packages.

Finally I went to the IDLE of Python 3.4.2 and wrote (this happened before copying the fine into the Python directory):

import cv2
Traceback (most recent call last):
  File "<pyshell#0>", line 1, in <module>
    import cv2
ImportError: No module named 'cv2'

And this happened after I copied the file into the Python directory:

import cv2
Traceback (most recent call last):
  File "<pyshell#3>", line 1, in <module>
    import cv2
ImportError: DLL load failed: The specified module could not be found.

What am I doing wrong? I not sure whether I should install CMake and NumPy.

Also I am not sure how to use this webpage (recommended by so many people), http://www.lfd.uci.edu/~gohlke/pythonlibs/#opencv, where many Python libraries are available, including PIL, OpenCV, VideoCapture, etc...

I want to try to run the examples from:

• Face Detection in Python Using a Webcam

• 1: Introduction to Python and OpenCV

• Face Detection With OS X and Python

OK, I should not use the file from Python 2.7 in Python 3.4. It won't work. I deleted it, so as otterb suggested, I just installed the opencv_python‑3.0.0‑cp34‑none‑win_amd64.whl package from http://www.lfd.uci.edu/~gohlke/pythonlibs/#opencv, but this file is an .whl not an EXE file, and according to How do I install a Python package with a .whl file? I followed these steps:

1. Go to the command prompt

2. Change directory with "cd" to where I downloaded the file

3. And write "pip install opencv_python-3.0.0-cp34-none-win_amd64.whl"

But I got the following message in red:

Installing collected packages: opencv-python
Cleaning up...
  Exception:
Traceback (most recent call last):
  File "C:\Python34\lib\shutil.py", line 370, in _rmtree_unsafe
    os.unlink(fullname)
PermissionError: [WinError 32] The process cannot access the file because it     is
being used by another process:     'C:\\Users\\JOSEFG~1\\AppData\\Local\\Temp\\pip-n
kyo0c6u-build\\opencv_python-3.0.0.data\\data\\Lib\\site-packages\\cv2.pyd'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Python34\lib\site-packages\pip\commands\install.py", line 283, in     run

    requirement_set.install(install_options, global_options,     root=options.root_p
ath)
  File "C:\Python34\lib\site-packages\pip\req.py", line 1444, in install
    requirement.remove_temporary_source()
  File "C:\Python34\lib\site-packages\pip\req.py", line 761, in     remove_temporary
_source
    rmtree(self._temp_build_dir)
  File "C:\Python34\lib\site-packages\pip\util.py", line 43, in rmtree
    onerror=rmtree_errorhandler)
  File "C:\Python34\lib\shutil.py", line 477, in rmtree
    return _rmtree_unsafe(path, onerror)
  File "C:\Python34\lib\shutil.py", line 367, in _rmtree_unsafe
    _rmtree_unsafe(fullname, onerror)
  File "C:\Python34\lib\shutil.py", line 367, in _rmtree_unsafe
    _rmtree_unsafe(fullname, onerror)
  File "C:\Python34\lib\shutil.py", line 367, in _rmtree_unsafe
    _rmtree_unsafe(fullname, onerror)
  File "C:\Python34\lib\shutil.py", line 367, in _rmtree_unsafe
    _rmtree_unsafe(fullname, onerror)
  File "C:\Python34\lib\shutil.py", line 372, in _rmtree_unsafe
    onerror(os.unlink, fullname, sys.exc_info())
  File "C:\Python34\lib\site-packages\pip\util.py", line 53, in rmtree_errorhandler
    (exctype is PermissionError and value.args[3] == 5) #python3.3
IndexError: tuple index out of range

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Python34\lib\shutil.py", line 370, in _rmtree_unsafe
    os.unlink(fullname)
PermissionError: [WinError 32] The process cannot access the file because it is being used by another process: 'C:\\Users\\JOSEFG~1\\AppData\\Local\\Temp\\pip-nkyo0c6u-build\\opencv_python-3.0.0.data\\data\\Lib\\site-packages\\cv2.pyd'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Python34\lib\site-packages\pip\basecommand.py", line 122, in main
    status = self.run(options, args)
  File "C:\Python34\lib\site-packages\pip\commands\install.py", line 302, in run

    requirement_set.cleanup_files(bundle=self.bundle)
  File "C:\Python34\lib\site-packages\pip\req.py", line 1319, in cleanup_files
    req.remove_temporary_source()
  File "C:\Python34\lib\site-packages\pip\req.py", line 761, in remove_temporary_source
    rmtree(self._temp_build_dir)
  File "C:\Python34\lib\site-packages\pip\util.py", line 43, in rmtree
    onerror=rmtree_errorhandler)
  File "C:\Python34\lib\shutil.py", line 477, in rmtree
    return _rmtree_unsafe(path, onerror)
  File "C:\Python34\lib\shutil.py", line 367, in _rmtree_unsafe
    _rmtree_unsafe(fullname, onerror)
  File "C:\Python34\lib\shutil.py", line 367, in _rmtree_unsafe
    _rmtree_unsafe(fullname, onerror)
  File "C:\Python34\lib\shutil.py", line 367, in _rmtree_unsafe
    _rmtree_unsafe(fullname, onerror)
  File "C:\Python34\lib\shutil.py", line 367, in _rmtree_unsafe
    _rmtree_unsafe(fullname, onerror)
  File "C:\Python34\lib\shutil.py", line 372, in _rmtree_unsafe
    onerror(os.unlink, fullname, sys.exc_info())
  File "C:\Python34\lib\site-packages\pip\util.py", line 53, in rmtree_errorhandler
    (exctype is PermissionError and value.args[3] == 5) #python3.3
IndexError: tuple index out of range

  Storing debug log for failure in C:\Users\me\pip\pip.log

Which means after reading it carefully that the file is unsafe to install on my PC.

Also it seems that pip should be the latest one to run the previous command according to How do I install pip on Windows?. Then I just upgrade pip in the command prompt with

python -m pip install -U pip

Now I have version 7.1. I know it by writing:

pip --version

Then I tried again

pip install opencv_python-3.0.0-cp34-none-win_amd64.whl

But it seems that it is working as I am getting this message:

C:\Users\Jose F Gomez D\Downloads>pip install opencv_python-3.0.0-cp34-none-win_amd64.whl
Requirement already satisfied (use --upgrade to upgrade): opencv-python==3.0.0 from file:///C:/Users/Jose%20F%20Gomez%20D/Downloads/opencv_python-3.0.0-cp34-none-win_amd64.whl in c:\python34\lib\site-packages

then I write in the python shell "import cv2" but there is a new error

ImportError: numpy.core.multiarray failed to import
Traceback (most recent call last):
  File "<pyshell#0>", line 1, in <module>
    import cv2
ImportError: numpy.core.multiarray failed to import

so I installed the numpy (and scipy just in case) library with

pip install numpy
pip install scipy

But it is not working as it requires C++

error microsoft visual c++ 10 is required

I tried to find "Visual C++ 2010 Express" from the webpage of Visual Studio at https://www.visualstudio.com/, but there is no link to "Microsoft Visual C++ 2010 express", so I went to page http://microsoft-visual-cpp-express.soft32.com/free-download/, downloaded the file, executed it, and now I got C++.

Again I went to the command prompt and tried to install NumPy and SciPy and it did not work. There is an error in the path:

ValueError: ['path']

OK, now I tried to install the NumPy and SciPy packages from:

http://sourceforge.net/projects/numpy/files/NumPy/

But it did not work, so I went to Gohike, http://www.lfd.uci.edu/~gohlke/pythonlibs/#numpy, and installed NumPy and SciPy from the command prompt in administrator mode:

pip install scipy‑0.16.0‑cp34‑none‑win_amd64.whl
pip install numpy‑1.9.2+mkl‑cp34‑none‑win_amd64.whl

Now I tried to run cv, but nothing. Uups, it's cv2, and it is working. I will write the answer next.

Answer 1

The right way to install OpenCV 3.0.0 for Python 3.4.2 on Windows 8.1:

1. Go to http://www.lfd.uci.edu/~gohlke/pythonlibs/#opencv
2. Download OpenCV, NumPy and SciPy

For me I needed:

• opencv_python-3.0.0-cp34-none-win_amd64.whl

• scipy‑0.16.0‑cp34‑none‑win_amd64.whl

• numpy‑1.9.2+mkl‑cp34‑none‑win_amd64.whl

  3. Download and install Visual C++ 2010 Express from http://microsoft-visual-cpp-express.soft32.com/free-download/
  4. Open a command prompt as administrator
  5. Change directory like "cd C:\Users\me\Downloads" to where I downloaded the file
  6. Copy and paste this: "python -m pip install -U pip"

  7. Then install the libraries. Copy and paste this:

     pip install opencv_python-3.0.0-cp34-none-win_amd64.whl

     pip install scipy‑0.16.0‑cp34‑none‑win_amd64.whl

     pip install numpy‑1.9.2+mkl‑cp34‑none‑win_amd64.whl

That is all.

-------------> Tricky Python <------------

Answer 2

You can use pip to install the whl file like:

pip install path/to/whlfile

Yes, you are right. Gohlke's package used to be an EXE file file, but OpenCV is now distributed as whl. Sorry I missed that.

Here is a similar Stack Overflow question: How do I install a Python package with a .whl file?

Answer 3

I have successfully installed OpenCV 3.1.0 using conda (install Anaconda 3 - 64 bit ) with the following command (conda installation of OpenCV 3):

conda install -c menpo opencv3=3.1.0

Please note that the only complete installation is obtained compiling the OpenCV libraries from the GitHub repository. I have found that some features (e.g. SURF detection) are missing from the conda installation and also from the wheels.

Answer 4

I did everything as mentioned by Jose Fernando Gomez Davila except I installed numpy before scipy as numpy is required to install scipy

pip install opencv_python-4.1.2-cp37-cp37m-win_amd64.whl

pip install scipy-1.4.1-cp37-cp37m-win_amd64.whl

pip install numpy-1.16.6+mkl-cp37-cp37m-win_amd64.whl