Image_Processing

Image Processing Workshop at IIT KHARAGPUR

Installation of OpenCV3 on Ubuntu:

Step 1: Update packages

  sudo apt-get update
  sudo apt-get upgrade

Step 2: Install OS libraries

  #Remove any previous installations of x264</h3>
  sudo apt-get remove x264 libx264-dev

  #We will Install dependencies now
  sudo apt-get install build-essential checkinstall cmake pkg-config yasm
  sudo apt-get install git gfortran
  sudo apt-get install libjpeg8-dev libjasper-dev libpng12-dev

  # If you are using Ubuntu 14.04
  sudo apt-get install libtiff4-dev
  # If you are using Ubuntu 16.04
  sudo apt-get install libtiff5-dev

  sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libdc1394-22-dev
  sudo apt-get install libxine2-dev libv4l-dev
  sudo apt-get install libgstreamer0.10-dev libgstreamer-plugins-base0.10-dev
  sudo apt-get install qt5-default libgtk2.0-dev libtbb-dev
  sudo apt-get install libatlas-base-dev
  sudo apt-get install libfaac-dev libmp3lame-dev libtheora-dev
  sudo apt-get install libvorbis-dev libxvidcore-dev
  sudo apt-get install libopencore-amrnb-dev libopencore-amrwb-dev
  sudo apt-get install x264 v4l-utils

  # Optional dependencies
  sudo apt-get install libprotobuf-dev protobuf-compiler
  sudo apt-get install libgoogle-glog-dev libgflags-dev
  sudo apt-get install libgphoto2-dev libeigen3-dev libhdf5-dev doxygen

Step 3: Install Python libraries

  sudo apt-get install python-dev python-pip python3-dev python3-pip
  sudo -H pip2 install -U pip numpy
  sudo -H pip3 install -U pip numpy

  # Install virtual environment
  sudo pip2 install virtualenv virtualenvwrapper
  sudo pip3 install virtualenv virtualenvwrapper
  echo "# Virtual Environment Wrapper"  >> ~/.bashrc
  echo "source /usr/local/bin/virtualenvwrapper.sh" >> ~/.bashrc
  source ~/.bashrc

  ############ For Python 2 ############
  # create virtual environment
  mkvirtualenv facecourse-py2 -p python2
  workon facecourse-py2

  # now install python libraries within this virtual environment
  pip install numpy scipy matplotlib scikit-image scikit-learn ipython

  # quit virtual environment
  deactivate
  ######################################

  ############ For Python 3 ############
  # create virtual environment
  mkvirtualenv facecourse-py3 -p python3
  workon facecourse-py3

  # now install python libraries within this virtual environment
  pip install numpy scipy matplotlib scikit-image scikit-learn ipython

  # quit virtual environment
  deactivate
  ######################################

Step 4: Download OpenCV and OpenCV_contrib

Step 4.1: Download opencv from Github

  git clone https://github.com/opencv/opencv.git
  cd opencv 
  git checkout 3.3.1 
  cd ..

Step 4.2: Download opencv_contrib from Github

  git clone https://github.com/opencv/opencv_contrib.git
  cd opencv_contrib
  git checkout 3.3.1
  cd ..

Step 5: Compile and install OpenCV with contrib modules

Step 5.1: Create a build directory

  cd opencv
  mkdir build
  cd build

Step 5.2: Run CMake

  cmake -D CMAKE_BUILD_TYPE=RELEASE \
    -D CMAKE_INSTALL_PREFIX=/usr/local \
    -D INSTALL_C_EXAMPLES=ON \
    -D INSTALL_PYTHON_EXAMPLES=ON \
    -D WITH_TBB=ON \
    -D WITH_V4L=ON \
    -D WITH_QT=ON \
    -D WITH_OPENGL=ON \
    -D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib/modules \
    -D BUILD_EXAMPLES=ON ..

Step 5.3: Compile and Install

  # find out number of CPU cores in your machine
  nproc
  # substitute 4 by output of nproc
  make -j4
  sudo make install
  sudo sh -c 'echo "/usr/local/lib" >> /etc/ld.so.conf.d/opencv.conf'
  sudo ldconfig

Step 5.4: Create symlink in virtual environment

Depending upon Python version you have, paths would be different. OpenCV’s Python binary (cv2.so) can be installed either in directory site-packages or dist-packages. Use the following command to find out the correct location on your machine.

  find /usr/local/lib/ -type f -name "cv2*.so"

It should output paths similar to one of these (or two in case OpenCV was compiled for both Python2 and Python3):

  ############ For Python 2 ############
  ## binary installed in dist-packages
  /usr/local/lib/python2.6/dist-packages/cv2.so
  /usr/local/lib/python2.7/dist-packages/cv2.so
  ## binary installed in site-packages
  /usr/local/lib/python2.6/site-packages/cv2.so
  /usr/local/lib/python2.7/site-packages/cv2.so

  ############ For Python 3 ############
  ## binary installed in dist-packages
  /usr/local/lib/python3.5/dist-packages/cv2.cpython-35m-x86_64-linux-gnu.so
  /usr/local/lib/python3.6/dist-packages/cv2.cpython-36m-x86_64-linux-gnu.so
  ## binary installed in site-packages
  /usr/local/lib/python3.5/site-packages/cv2.cpython-35m-x86_64-linux-gnu.so
  /usr/local/lib/python3.6/site-packages/cv2.cpython-36m-x86_64-linux-gnu.so

Double check the exact path on your machine before running the following commands

  ############ For Python 2 ############
  cd ~/.virtualenvs/facecourse-py2/lib/python2.7/site-packages
  ln -s /usr/local/lib/python2.7/dist-packages/cv2.so cv2.so

  ############ For Python 3 ############
  cd ~/.virtualenvs/facecourse-py3/lib/python3.6/site-packages
  ln -s /usr/local/lib/python3.6/dist-packages/cv2.cpython-36m-x86_64-linux-gnu.so cv2.so

Running OpenCV codes

In C++:

  g++ filename.cpp `pkg-config --cflags --libs opencv`
  ./a.out

In python:

  ############ For Python 2 ############
  workon facecourse-py2
  ############ For Python 3 ############
  workon facecourse-py3
  
  python filename.py
  
  deactivate