Why cv2.so missing after opencv installed?

Question

Today I installed opencv 2.4.4 to Ubuntu 12.10

But import cv2 not works.

root@-:~# python
Python 2.7.3 (default, Sep 26 2012, 21:53:58) 
[GCC 4.7.2]          


        

Answer 1

I have this problem in my OS X El Capitan.

I followed the instructions mentioned in this tutorial. Didn't get a successful working install and had the above error of missing cv2.so file in the required folders mentioned and at the python prompt.

Finally figured that using the virtual python setup was causing trouble. So uninstalled with

pip install virtualenv virtualenvwrapper

Then ran

brew link opencv

which threw errors.

And then followed below steps to resolve the issue.

First run

brew link opencv

If it gives an error, try for an automated diagnosis

brew doctor

brew doctor gives a list of problems that could be leading to errors in installation process.

To fix problems in case of conflicting files, run to get a list of all actions which will be performed by overwrite without actually performing them.

To list all files that would be deleted:

  brew link --overwrite --dry-run opencv

followed by this run which will execute the overwrite, assuming you feel that the actions performed by overwrite will take your system to a more stable state.

To force the link and overwrite all conflicting files:

 brew link --overwrite opencv

This tutorial is a simpler alternative.

Answer 2

I install python-opencv to solve my problem in Ubuntu 14.04 sh sudo apt-get install python-opencv

Answer 3

Using raspbian on a rasberry pi I had the problem of the module not being found also. I had three versions of python (2.6, 2.7, and 3.2), be sure you are using python2.7. You can check this by running:

python --version

I found that for my case it was simply that I needed to install python-dev.

sudo apt-get install python-dev

I did Not have to remove and reinstall opencv, I tried my hardest to avoid that, knowing that it takes a few hours to complete the process.

After installing python-dev I went to the file I built the opencv into, for me it was " ~/opencv-2.4.9/release", and told it to make

sudo make

after this I was able to find the cv2.so file. searching for it with:

find / -name "cv2.so"

at this point I found a few files. next I ran just the python to see if it could find "import" them

python 
>>> import cv2

no errors should come up.

>>> import numpy

I have heard that numpy was necessary for opencv to run. From there I believe you should be good to run your script, if no errors come about. I hope this helps.

The page that helped me is listed...

http://opencv-users.1802565.n2.nabble.com/I-can-t-find-cv-so-and-cv2-so-after-compiling-td6671937.html

Answer 4

In my case it was a problem with cmake:

sudo apt install software-properties-common
sudo add-apt-repository ppa:george-edison55/cmake-3.x
sudo apt update

If cmake is not yet installed:

sudo apt install cmake

If cmake is already installed:

sudo apt upgrade

For more information, see this link.

Answer 5

I had a similar problem when I manually configured using CMAKE on OSX El Capitan. I had given this additional option:

PYTHON2_PACKAGES_PATH='lib/python2.7/site-packages'

which stopped the cv2.so in that package from getting installed. It seems to install properly in my build folder after I removed it:

PYTHON2_EXECUTABLE='/usr/bin/python2.7'
PYTHON2_INCLUDE_DIR='/usr/include/python2.7'
PYTHON2_LIBRARY='/usr/lib/libpython2.7.dylib' # TODO - Fix for linux
PYTHON2_NUMPY_INCLUDE_DIRS='/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/numpy/core/include' # Todo - Fix for linux


cd $OPENCV_DIR

cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=$OPENCV_INSTALL_PATH \
                                  -D WITH_CUDA=OFF \
                                  -D BUILD_opencv_python2:BOOL=ON \
                                  -D PYTHON2_EXECUTABLE=$PYTHON2_EXECUTABLE \
                                  -D PYTHON2_INCLUDE_DIR=$PYTHON2_INCLUDE_DIR \
                                  -D PYTHON2_LIBRARY=$PYTHON2_LIBRARY \
                                  -D PYTHON2_NUMPY_INCLUDE_DIRS=$PYTHON2_NUMPY_INCLUDE_DIRS \
                                  -D INSTALL_PYTHON_EXAMPLES:BOOL=ON \
                                  ..
make -j8
make install

Answer 6

I came across similar problem. After digging into this a little more I came across a post where it was mentioned that python-numpy package was required. So, I uninstalled the opencv by running the following command in build folder(in your case release folder):

dpkg -r build

Then I removed all the opencv files. I installed python-numpy and python-dev with this command:

sudo apt-get install python-dev python-numpy

Then, after re-running the installation script, import cv2 command in python console doesn't give me any error and is properly imported.