Sample code for Image Processing using OpenCV and C++

Build project

git clone <this_repository>
cd <folder>
make
./DisplayImage

You should see this :

and this in terminal :

Install OpenCV on Linux

0 - créate sample code for tests :

#include <iostream>
#include <opencv2/opencv.hpp>
#include <opencv2/highgui.hpp>

using namespace std;

int main()
{
    cv::Mat image;
    image = cv::imread("images/hello_iMac.png", 1);
 
    cv::namedWindow("Display Image", cv::WINDOW_AUTOSIZE);
    cv::imshow("Display Image", image);
    cv::waitKey(0);
    return 0;
}

1- Install dependencies:

sudo apt-get update sudo apt-get upgrade sudo apt-get install libgtk2.0-dev pkg-config

2- To compile OpenCV you will need a C++ compiler. Usually it is G++/GCC or Clang/LLVM. also OpenCV uses CMake build configuration tool:

sudo apt install -y g++ sudo apt-get install cmake make

3- Clone repository using git:

git clone https://github.com/opencv/opencv.git 
git clone https://github.com/opencv/opencv_contrib.git

4- Create build directory:

mkdir -p build && cd build

5- Configure-generate build scripts for the preferred build system:

cmake -DOPENCV_EXTRA_MODULES_PATH=../opencv_contrib/modules ../opencv

6- Build-run actual compilation process. 4 is number of used processor cores. this part may takes some minutes.

make -j4

7- Installation process copies files to predefined locations and do minor patching:

sudo make install

7.1- You can remove opencv if you want:

sudo make uninstall

8- Create a CMake file (CMakeLists.txt) . the name of the source code is DisplayImage.cpp for example:

cmake_minimum_required(VERSION 2.8)
project( DisplayImage )
find_package( OpenCV REQUIRED )
include_directories( ${OpenCV_INCLUDE_DIRS} )
add_executable( DisplayImage main.cpp )
target_link_libraries( DisplayImage ${OpenCV_LIBS} )

9- Generate the executable. This part is easy, just proceed as with any other project using CMake:

cd <DisplayImage_directory> cmake . make

10- run executable file:

./DisplayImage

11 - enjoy ;)