How to install OpenCV in FEDORA OS

In this post you will learn how to install OpenCV in your Fedora OS. This post is experimented in Fedora 20.

Requirements:

•  Internet connection
• FEDORA with latest updates running on your system.
•  Manually downloaded latest opencv zipped file for linux from opencv website.(We will not download through Terminal utility).

Procedures:

1.   Open the Terminal app
2.  go to Desktop using cd Desktop command
3. Let us install the Dependencies

     sudo yum install cmake pkgconfig gtk2 gcc gcc-c++

          (this will install basic packages required for opencv to run)

    4. Now we will install ffmpeg package(one more extra package)

sudo rpm -Uvh http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-stable.noarch.rpm http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm

type the following          

  sudo yum –y install ffmpeg

   5. So far, we have installed all the basic packages required

   6. Create a folder known as “OpenCV” in your desktop using GUI and                                    mouse+rightclick+create_new_folder

   7. Copy the zipped opencv file inside the “OpenCV” folder using mouse or keyboard

   8. Right click on the file and extract it. Once extract is done you should be able to                notice a directory “opencv-2.4.x”, where x is the version of opencv that you have          downloaded.

   9. Create a folder named “build” inside “opencv-2.4.x” directory

(From step 6 to 9, we could have done these steps through terminal but to simplify your life we made use of GUI,mouse and keyboard)

   10. Now in terminal

           cd opencv-2.4.x/build

 11. Now we will build the opencv and install it using cmake tool that you installed in             3rd step and make tool

  12. Run the following commands

               cmake –D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local –D WITH_TBB=ON -D WITH_EIGEN=ON ..

     (don’t miss the two dots)

               make

     (This will take little time to generate build of opencv. Once it finishes to 100%, run the following command)

              sudo make install

          (this will install opencv library in /usr/local directory)

        13. Once the installation is done we need to inform certain utility that opencv is                      available in the system for linking. One such utility we use is “pkg-config”

        14.  Open new file “opencv.conf” using vi editor

                 sudo /etc/ld.so.conf.d/opencv.conf

      add this statement in the file(press “i” to get insert mode of vi)

                                        /usr/local/lib

            once done press ESC, then :wq for saving the new created file opencv.conf and exit from vi editor

       15. Then type  sudo ldconfig in terminal

         16. Then type sudo vi /etc/profile

      add the following line in the file(press “i” to get insert mode of vi)

                 export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig

                 export LD_LIBRARY_PATH=/usr/local/lib

              once done press ESC, then :wq for saving the new created file opencv.conf and            exit from vi editor

        17.type source /etc/profile

Thus we have finished configuring part.So now you have configured pkg-config utility

 to identify the opencv . 

Now let us run a small program to check the opencv installation

• save this code in a file with name as "abc.cpp"

• change the path of the image in imread command with your own image available in hard disk(do not use this \, use only /, to separate directories) 

• to compile it 

 #include<opencv2/highgui/highgui.hpp>

using namespace cv ;

 int main()

{

     Mat img = imread("/home/USER/Pictures/python.jpg",CV_LOAD_IMAGE_COLOR);

     imshow("opencvtest",img);

     waitKey(0);

     return 0;

}

• g++ 'pkg-config --cflags opencv' abc.cpp 'pkg-config --libs opencv' -o abc 

• which generates executable named as "abc", now run the abc
• ./abc

By now you must see your image being loaded up in a window
Thus, OpenCV is properly configured in your Linux system
Note: Never ever forget to add header files as shown above in the code(dont miss "opencv2/")
Other header file available in OpenCV are as follows

#include "opencv2/core/core_c.h"
#include "opencv2/core/core.hpp"
#include "opencv2/flann/miniflann.hpp"
#include "opencv2/imgproc/imgproc_c.h"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/photo/photo.hpp"
#include "opencv2/video/video.hpp"
#include "opencv2/features2d/features2d.hpp"
#include "opencv2/objdetect/objdetect.hpp"
#include "opencv2/calib3d/calib3d.hpp"
#include "opencv2/ml/ml.hpp"
#include "opencv2/highgui/highgui_c.h"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/contrib/contrib.hpp"

or simply add #include "opencv2/opencv.hpp" which includes all the header file mentioned above