Merge pull request #10056 from akhilesh-k:master

Added Python setup docs for Ubuntu Machines (#10056)

doc/py_tutorials/py_setup/py_setup_in_ubuntu/py_setup_in_ubuntu.markdown

@@ -0,0 +1,165 @@
+Install OpenCV-Python in Ubuntu {#tutorial_py_setup_in_ubuntu}
+===============================
+
+Goals
+-----
+
+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:
+- Install from pre-built binaries available in Ubuntu repositories
+- Compile from the source. In this section, we will see both.
+
+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.
+
+Installing OpenCV-Python from Pre-built Binaries
+------------------------------------------------
+
+This method serves best when using just for programming and developing OpenCV applications.
+
+Install package [python-opencv](https://packages.ubuntu.com/trusty/python-opencv) with following command in terminal (as root user).
+
+```
+$ sudo apt-get install python-opencv
+```
+
+Open Python IDLE (or IPython) and type following codes in Python terminal.
+
+```
+import cv2
+print(cv2.__version__)
+```
+
+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.
+
+Building OpenCV from source
+---------------------------
+
+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.
+
+### Required build dependencies
+
+We need **CMake** to configure the installation, **GCC** for compilation, **Python-devel** and
+**Numpy** for building Python bindings etc.
+
+```
+sudo apt-get install cmake
+sudo apt-get install python-devel numpy
+sudo apt-get install gcc gcc-c++
+```
+
+Next we need **GTK** support for GUI features, Camera support (libv4l), Media Support
+(ffmpeg, gstreamer) etc.
+
+```
+sudo apt-get install gtk2-devel
+sudo apt-get install libv4l-devel
+sudo apt-get install ffmpeg-devel
+sudo apt-get install gstreamer-plugins-base-devel
+```
+
+### Optional Dependencies
+
+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.
+
+```
+sudo apt-get install libpng-devel
+sudo apt-get install libjpeg-turbo-devel
+sudo apt-get install jasper-devel
+sudo apt-get install openexr-devel
+sudo apt-get install libtiff-devel
+sudo apt-get install libwebp-devel
+```
+
+### Downloading OpenCV
+
+To download the latest source from OpenCV's [GitHub Repository](https://github.com/opencv/opencv).
+(If you want to contribute to OpenCV choose this. For that, you need to install **Git** first)
+
+```
+$ sudo apt-get install git
+$ git clone https://github.com/opencv/opencv.git
+```
+
+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.
+
+```
+$ mkdir build
+$ cd build
+```
+
+### Configuring and Installing
+
+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):
+
+```
+$ cmake ../
+```
+
+OpenCV defaults assume "Release" build type and installation path is "/usr/local".
+For additional information about CMake options refer to OpenCV @ref tutorial_linux_install "C++ compilation guide":
+
+You should see these lines in your CMake output (they mean that Python is properly found):
+
+```
+--   Python 2:
+--     Interpreter:                 /usr/bin/python2.7 (ver 2.7.6)
+--     Libraries:                   /usr/lib/x86_64-linux-gnu/libpython2.7.so (ver 2.7.6)
+--     numpy:                       /usr/lib/python2.7/dist-packages/numpy/core/include (ver 1.8.2)
+--     packages path:               lib/python2.7/dist-packages
+--
+--   Python 3:
+--     Interpreter:                 /usr/bin/python3.4 (ver 3.4.3)
+--     Libraries:                   /usr/lib/x86_64-linux-gnu/libpython3.4m.so (ver 3.4.3)
+--     numpy:                       /usr/lib/python3/dist-packages/numpy/core/include (ver 1.8.2)
+--     packages path:               lib/python3.4/dist-packages
+```
+
+Now you build the files using "make" command and install it using "make install" command.
+
+```
+$ make
+# sudo make install
+```
+
+Installation is over.
+All files are installed in "/usr/local/" folder.
+Open a terminal and try import "cv2".
+
+```
+import cv2
+print(cv2.__version__)
+```

doc/py_tutorials/py_setup/py_table_of_contents_setup.markdown

@@ -15,3 +15,8 @@ Introduction to OpenCV {#tutorial_py_table_of_contents_setup}
 
     Set Up
     OpenCV-Python in Fedora
+
+-   @subpage tutorial_py_setup_in_ubuntu
+
+    Set Up
+    OpenCV-Python in Ubuntu