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

How to install opencv(cv2) with python bindings in Linux - Ubuntu/Fedora

1. Install gcc, g++/gcc-c++, cmake (apt-get or yum, in case of yum use gcc-c++)

   apt-get install gcc, g++, cmake
   

2. Downlaod latest opencv from openCV's website

3. Untar it with

   tar -xvf opencv-*
   

4. Inside the untarred folder make a new folder called release

   mkdir release
   cd release
   

   (or any folder name) and run this command in it

   cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D BUILD_NEW_PYTHON_SUPPORT=ON -D BUILD_EXAMPLES=ON ..
   

   the .. will pull files from the parents folder and will get the system ready for installation on your platform.

5. in the release folder run

   make
   

6. After about 2-3 mins of make processing when its finished run

   sudo make install
   

7. Export python path

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

That's it, now go to python and try

>>> import cv2

you should not get any error message.

Tested on python 2.7, should be virtually similar to python 3.x.

Answer 2

All above answers did not work for me, however, after a whole day struggling, I finally solved this problem.

To have cv2.so, we need:

1. At least python 2 or 3 installed. that why people say: sudo apt-get install python-dev. But that's not necessary, in my case, I use anaconda python. (there are many ways to install python)
2. numpy is also a must. so, whatever python you use, just make sure you have it downloaded. In my case, I use anaconda numpy. (anaconda have it installed already, for normal python, use pip install numpy)

To tell camke where the path is, just take my command as an example:

cmake -D CMAKE_BUILD_TYPE=RELEASE \
      -D CMAKE_INSTALL_PREFIX=/usr/local \
      -D OPENCV_EXTRA_MODULES_PATH=../opencv_contrib/modules \
      -D PYTHON2_EXECUTABLE='/home/parallels/anaconda2/bin/python' \
      -D PYTHON2_LIBRARY='/home/parallels/anaconda2/lib/python2.7' \
      -D PYTHON2_NUMPY_INCLUDE_DIRS='/home/parallels/anaconda2/lib/python2.7/site-packages/numpy/core/include' \
      -D BUILD_EXAMPLES=ON ..

for python3，you should (I'm using anaconda python, so I linked everything to anaconda):

cmake -D CMAKE_BUILD_TYPE=Release \
      -D CMAKE_INSTALL_PREFIX=/usr/local \
      -D OPENCV_EXTRA_MODULES_PATH=../opencv_contrib-3.3.1/modules \
      -D PYTHON3_EXECUTABLE='/home/test/SoftWare/anaconda3/bin/python3.6m' \
      -D PYTHON_INCLUDE_DIR='/home/test/SoftWare/anaconda3/include/python3.6m' \
      -D PYTHON3_LIBRARY='/home/test/SoftWare/anaconda3/lib/libpython3.6m.so' \
      -D PYTHON3_NUMPY_INCLUDE_DIRS='/home/test/SoftWare/anaconda3/lib/python3.6/site-packages/numpy/core/include' \
      -D PYTHON3_PACKAGES_PATH='/home/test/SoftWare/anaconda3/lib/python3.6/site-packages' ..

One thing to remember!!! before you enter cmake ... 1. clean your build folder, 2. Only camke once! otherwise you can not change ** PYTHON3_LIBRARY: NO**...(this is a bug I think)

I know there might be some useless arguments, but I am tired to try to clean them. Here's a screenshot of my cmake print info. screenshot of my cmake info

You can clearly see that, only python2 can generate cv2.so. python3 can not! (Python3 wrappers can not be generated).

Answer 3

None of the above worked for me; am in Ubuntu 16.04 on an ec2 instance & had anaconda installed so I just used

conda install opencv for both my conda2 and 3 installs