Ubuntu, how to install OpenCV for python3?

Question

I want to install OpenCV for python3 in ubuntu 16.04. Fist I tried running sudo apt-get install python3-opencv which is how I pretty much install all of my python software. This could not find a repository. The install does work however if I do sudo apt-get install python-opencv this issue with this is that by not adding the three to python it installs for python 2 which I do not use. I would really perfer not to have to build and install from source so is there a way I can get a repository? I also tried installing it with pip3 and it could not find it either.

Answer 1

Well this will be a lengthy answer, so let's start :

Step 1: Install prerequisites : Upgrade any pre-installed packages:

$ sudo apt-get update $ sudo apt-get upgrade 

Install developer tools used to compile OpenCV 3.0:

$ sudo apt-get install build-essential cmake git pkg-config 

Install libraries and packages used to read various image and videos formats from disk:

$ sudo apt-get install libjpeg8-dev libtiff5-dev libpng-dev libavcodec-dev libavformat-dev libswscale-dev libv4l-dev 

Install GTK so we can use OpenCV’s GUI features:

$ sudo apt-get install libgtk2.0-dev 

Install packages that are used to optimize various functions inside OpenCV, such as matrix operations:

$ sudo apt-get install libatlas-base-dev gfortran 

Step 2: Setup Python (Part 1)

Let’s download pip , a Python package manager, installed for Python 3:

$ wget https://bootstrap.pypa.io/get-pip.py $ sudo python3 get-pip.py 

Let’s use our fresh pip3 install to setup virtualenv and virtualenvwrapper :

$ sudo pip3 install virtualenv virtualenvwrapper 

Now we can update our ~/.bashrc file (place at the bottom of the file):

# virtualenv and virtualenvwrapper export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3 export WORKON_HOME=$HOME/.virtualenvs source /usr/local/bin/virtualenvwrapper.sh $ source ~/.bashrc $ mkvirtualenv cv 

Step 2: Setup Python (Part 2)

we’ll need to install the Python 3.4+ headers and development files:

$ sudo apt-get install python3.4-dev 

OpenCV represents images as NumPy arrays, so we need to install NumPy into our cv virtual environment:

$ pip install numpy 

Step 3: Build and install OpenCV 3.0 with Python 3.4+ bindings

$ cd ~ $ git clone https://github.com/opencv/opencv.git $ cd opencv $ git checkout 3.0.0 $ cd ~ $ git clone https://github.com/opencv/opencv_contrib.git $ cd opencv_contrib $ git checkout 3.0.0 

Time to setup the build:

$ cd ~/opencv $ mkdir build $ cd build $ cmake -D CMAKE_BUILD_TYPE=RELEASE \     -D CMAKE_INSTALL_PREFIX=/usr/local \     -D INSTALL_C_EXAMPLES=ON \     -D INSTALL_PYTHON_EXAMPLES=ON \     -D OPENCV_EXTRA_MODULES_PATH=~/opencv_contrib/modules \     -D BUILD_EXAMPLES=ON .. 

Let's start OpenCV compile process :

$ make -j4 

Assuming OpenCV 3.0 compiled without error, you can now install it on your system:

$ sudo make install $ sudo ldconfig 

Step 4: Sym-link OpenCV 3.0

If you’ve reached this step, OpenCV 3.0 should now be installed in /usr/local/lib/python3.4/site-packages/.

Here, our OpenCV bindings are stored under the name cv2.cpython-34m.so

However, in order to use OpenCV 3.0 within our cv virtual environment, we first need to sym-link OpenCV into the site-packages directory of the cv environment, like this: (Be sure to take note of cv2.cpython-34m.so)

$ cd ~/.virtualenvs/cv/lib/python3.4/site-packages/ $ ln -s /usr/local/lib/python3.4/site-packages/cv2.cpython-34m.so cv2.so 

Notice how I am changing the name from cv2.cpython-34m.so to cv2.so — this is so Python can import our OpenCV bindings using the name cv2 .

Step 5: Test out the OpenCV 3.0 and Python 3.4+ install

$ workon cv $ python >>> import cv2 >>> cv2.__version__ '3.0.0' 

Hope that helps. Also, credit to Adrian Rosebrock on his post. It worked for me as a charm.