[python] Installing OpenCV for Python on Ubuntu, getting ImportError: No module named cv2.cv

I have an Ubuntu 14.04 system, on which I want to install OpenCV and use it with Python 2.x.

I installed OpenCV using the instructions here: https://help.ubuntu.com/community/OpenCV

The install seemed to run properly, no errors, the script ended with output

OpenCV 2.4.9 ready to be used

When I try to run the sample Python script, I get the following:

$ python opencv.py
Traceback (most recent call last):
  File "opencv.py", line 1, in <module>
    from cv2.cv import *
ImportError: No module named cv2.cv

I suspect I know why, I just don't know how to fix it. OpenCV installed to the current directory I was in when I ran the install script, it's a subdirectory of my home folder.

Others who get this import error after install seem to be having a path issue, and have luck adding this to their code:

import sys
sys.path.append('/usr/local/lib/python2.7/site-packages')

or updating their PYTHONPATH with that same directory. I tried adding that code, it doesn't make a difference. I don't see any files in the "site-packages" directory. Should I have done the install in that directory? I imagine the installation instructions would have spelled that out. I suspect that my problem has to do with Python not finding the OpenCV install, but I'm not sure how to proceed.

Please help me get a usable install of OpenCV as simply as possible.

I think you don't have the python-opencv package.

I had the exact same problem and

sudo apt-get install python-opencv

solved the issue for me.

you can install opencv from the following link https://www.learnopencv.com/install-opencv3-on-ubuntu/ It works for me . apt-get install doesnt contain many packages of opencv

Try conda install -c conda-forge opencv if you are using anaconda, it works!

If you really sure that you installed cv2 but it gives no module error. There is a solution for this. Probably you have cv2.so file in your directory

/usr/local/lib/python2.7/site-packages/cv2.so

move this cv2.so file to

/usr/lib/python2.7/site-packages

copy the file into site-packages directory

Use pip:

https://pypi.python.org/pypi/pip

$ pip install SomePackage
  [...]
  Successfully installed SomePackage

And when you add a path to PYTHONPATH with sys, PYTHONPATH it's always restarted to default values when you close your Python shell. Check this thread:

Permanently add a directory to PYTHONPATH

First add openCV to your path (Quick guide):

https://help.ubuntu.com/community/OpenCV

after that, install the non-python packages pyopencv depends on:

sudo apt-get build-dep python-opencv

finally, use pip:

pip install pyopencv

Also, you can check this tutorial to install openCV in ubuntu 14.04 LTS

http://www.samontab.com/web/2014/06/installing-opencv-2-4-9-in-ubuntu-14-04-lts/

If you want as simple as possible, install from the repository:

sudo apt-get install python-opencv libopencv-dev python-numpy python-dev

Verify if cv2.so did compile, should be placed in: /usr/local/lib/python2.7/site-packages Then export that path like this

export PYTHONPATH=/usr/local/lib/python2.7/site-packages:$PYTHONPATH

Same as in the answer here

My environment:

• Ubuntu 15.10
• Python 3.5

Since none of the previous answers worked for me, I downloaded OpenCV 3.0 from http://opencv.org/downloads.html and followed the installation manual. I used the following cmake command:

$ ~/Programs/opencv-3.0.0$ cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local -D PYTHON3_EXECUTABLE=/usr/bin/python3.5 -D PYTHON_INCLUDE_DIR=/usr/include/python3.5 -D PYTHON_INCLUDE_DIR2=/usr/include/x86_64-linux-gnu/python3.5m -D PYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.5m.so -D PYTHON3_NUMPY_INCLUDE_DIRS=/usr/lib/python3/dist-packages/numpy/core/include/ -D PYTHON3_PACKAGES_PATH=/usr/lib/python3/dist-packages ..

Each step of the tutorial is important. Particularly, don't forget to call sudo make install.

Try using: from cv2 import cv

It works for me.

You can build for source following the official OpenCV tutorial. The crucial part is to set the PYTHON3_EXECUTABLE, PYTHON_LIBRARY, PYTHON3_PACKAGES_PATH and PYTHON3_NUMPY_INCLUDE_DIRS parameters for python3.6. Here are all the steps:

1. Clone the repo

   git clone https://github.com/opencv/opencv.git
   

2. Create build directory

   cd ~/opencv
   mkdir build
   cd build
   

3. Configure

   cmake -D CMAKE_BUILD_TYPE=RELEASE \
         -D CMAKE_INSTALL_PREFIX=/usr/local .. \
         -D PYTHON_INCLUDE_DIR=/usr/include/python3.6 \
         -D PYTHON_INCLUDE_DIR2=/usr/include/x86_64-linux-gnu/python3.6m \
         -D BUILD_NEW_PYTHON_SUPPORT=ON \
         -D BUILD_opencv_python3=ON \
         -D HAVE_opencv_python3=ON \
         -D INSTALL_PYTHON_EXAMPLES=ON \
         -D PYTHON3_EXECUTABLE=/usr/bin/python3.6 \
         -D PYTHON_DEFAULT_EXECUTABLE=/usr/bin/python3.6 \
         -D PYTHON_LIBRARY=/usr/lib/x86_64-linux-gnu/libpython3.6m.so \
         -D PYTHON3_PACKAGES_PATH=/usr/lib/python3/dist-packages .. \
         -D PYTHON3_NUMPY_INCLUDE_DIRS=/home/user/.local/lib/python3.6/site-packages/numpy/core/include/
   

4. Build

   make -j8
   

5. Install libraries

   sudo make install
   

6. Test

   python3
   import cv2
   

If you don't get the error "No module named cv2", then the installation was successful.

Note: If you don't know the path to numpy for the PYTHON3_NUMPY_INCLUDE_DIRS parameter, you can find it by executing import numpy and then numpy.__file__ in a python3 shell.

I found a solution in the guide here:

http://www.samontab.com/web/2014/06/installing-opencv-2-4-9-in-ubuntu-14-04-lts/

I resorted to compiling and installing from source. The process was very smooth, had I known, I would have started with that instead of trying to find a more simple way to install. Hopefully this information is helpful to someone.

For those who are trying to use 3.1.0 but after installing python says "cv2 module not found".

You likely have python but not python-dev.

sudo apt-get install python-dev

then reinstall 3.1.0 and it'll work.

Find where the cv2.so is, for example /usr/local/lib/python2.7/dist-packages, then add this into your ~/.bashrc by doing:

sudo gedit ~/.bashrc

and add

export PYTHONPATH=/usr/local/lib/python2.7/dist-packages:$PYTHONPATH

In the last line

And then remember to open another terminal, this can be work, and I have solve my problem. Hope it can help you.

This seemed to work for me on Max OSX: https://anaconda.org/menpo/opencv3

conda install -c menpo opencv3=3.1.0

I confirmed that you can import cv2 in python using python2.7 and python3

I also had this issue. Tried different things. But finally

conda install opencv

worked for me.

I tried all the other options here, but I could not get import cv2 working with Anaconda on Ubuntu. This is the only thing that helped:

pip install opencv-python

Its complete installation nightmare, but I'll give one more hope you can avoid building opencv from source:

pip install opencv-contrib-python

For me, this problem was due to the fact that I had not appropriately sym-linked the cv2.so file in the~/.virtualenvs/cv/lib/python3.5/site-packages folder (the name of your virualenv may not be "cv", your version of python may not be 3.5--adjust accordingly).

If you go to the ~/.virtualenvs/cv/lib/python3.5/site-packages folder and ls, the cv2.so file should appear in light blue (Ubuntu 16.04) showing that it is linked. You can check the link location by typing: readlink cv2.so

If cv2.so appears in red (as mine did), rm the file and type: (for my install of python 3.5)

ln -s /usr/local/lib/python3.5/dist-packages/cv2.cpython-35m-x86_64-linux-gnu.so cv2.so

OR (if you have python 3.6)

ln -s /usr/local/lib/python3.6/dist-packages/cv2.cpython-36m-x86_64-linux-gnu.so cv2.so

If you are working in python 2.6 or python 2.7, you instead type:

ln -s /usr/local/lib/python2.7/dist-packages/cv2.so cv2.so

If the cv2.so or cv2.cpython-36m-x86_64-linux-gnu.so files do not exist in your /usr/local/lib/python***/dist-packages location, check to see if they're in a /usr/local/lib/python***/sites-packages folder. If so, adjust the path accordingly. If not, something has gone wrong with your opencv installation.

This answer was inspired by information here: https://www.pyimagesearch.com/2016/10/24/ubuntu-16-04-how-to-install-opencv/

if you are using pycharm platform it's very simple go into view=>tool windows==>python console after that you will see in the bottom the console with [1] : type this !pip install opencv-python

try using sudo apt install python3-opencv

it will install the latest package of open cv.

Or you could try reinstalling the opencv package. It might have got corrupted during installation.

Create a symbolic link to OpenCV. Eg:

cd ~/.virtualenvs/cv/lib/python2.7/site-packages/
ln -s /usr/local/lib/python2.7/dist-packages/cv2.so cv2.so
ln -s /usr/local/lib/python2.7/dist-packages/cv.py cv.py