In this tutorial We will learn to setup OpenCV-Python in Ubuntu System. Below steps are tested for Ubuntu 16.04 (64-bit) and Ubuntu 14.04 (32-bit).
OpenCV-Python can be installed in Ubuntu in two ways:
Another important thing is the additional libraries required. OpenCV-Python requires only Numpy (in addition to other dependencies, which we will see later). But in this tutorials, we also use Matplotlib for some easy and nice plotting purposes (which I feel much better compared to OpenCV). Matplotlib is optional, but highly recommended. Similarly we will also see IPython, an Interactive Python Terminal, which is also highly recommended.
This method serves best when using just for programming and developing OpenCV applications.
Install package python-opencv with following command in terminal (as root user).
Open Python IDLE (or IPython) and type following codes in Python terminal.
If the results are printed out without any errors, congratulations !!! You have installed OpenCV-Python successfully.
It is quite easy. But there is a problem with this. Apt repositories may not contain the latest version of OpenCV always. For example, at the time of writing this tutorial, apt repository contains 2.4.8 while latest OpenCV version is 3.x. With respect to Python API, latest version will always contain much better support and latest bug fixes.
So for getting latest source codes preference is next method, i.e. compiling from source. Also at some point in time, if you want to contribute to OpenCV, you will need this.
Compiling from source may seem a little complicated at first, but once you succeeded in it, there is nothing complicated.
First we will install some dependencies. Some are required, some are optional. You can skip optional dependencies if you don't want.
We need CMake to configure the installation, GCC for compilation, Python-devel and Numpy for building Python bindings etc.
Next we need GTK support for GUI features, Camera support (libv4l), Media Support (ffmpeg, gstreamer) etc.
Above dependencies are sufficient to install OpenCV in your Ubuntu machine. But depending upon your requirements, you may need some extra dependencies. A list of such optional dependencies are given below. You can either leave it or install it, your call :)
OpenCV comes with supporting files for image formats like PNG, JPEG, JPEG2000, TIFF, WebP etc. But it may be a little old. If you want to get latest libraries, you can install development files for system libraries of these formats.
To download the latest source from OpenCV's GitHub Repository. (If you want to contribute to OpenCV choose this. For that, you need to install Git first)
It will create a folder "opencv" in current directory. The cloning may take some time depending upon your internet connection.
Now open a terminal window and navigate to the downloaded "opencv" folder. Create a new "build" folder and navigate to it.
Now we have all the required dependencies, let's install OpenCV. Installation has to be configured with CMake. It specifies which modules are to be installed, installation path, which additional libraries to be used, whether documentation and examples to be compiled etc. Most of this work are done automatically with well configured default parameters.
Below command is normally used for configuration of OpenCV library build (executed from build folder):
OpenCV defaults assume "Release" build type and installation path is "/usr/local". For additional information about CMake options refer to OpenCV C++ compilation guide:
You should see these lines in your CMake output (they mean that Python is properly found):
Now you build the files using "make" command and install it using "make install" command.
Installation is over. All files are installed in "/usr/local/" folder. Open a Python terminal and try import "cv2".