13. External Libraries

1- Copy this code to your editor and save it on your VM Desktop as LoadImage.cpp:

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

using namespace cv;
using namespace std;

int main( )
{ 
    Mat image = imread("Udacity.png", CV_LOAD_IMAGE_COLOR);                                

    namedWindow( "Display window", WINDOW_AUTOSIZE );    

    imshow( "Display window", image );                   

    cout << image;

    waitKey(0);                                          

    return 0;
}                                                                                                                                                            

2- Now, open a Linux terminal and install the OpenCv library:

$ sudo apt install libopencv-dev

3- Enter the password when prompted:

$ robo-nd

4- Do a quick check to verify the installation of OpenCV library on the system.

$ pkg-config --libs opencv

You should be able to see all the library files in the Linux terminal which indicates that OpenCV is now installed.

5- Then, download the Udacity image and store it on your Desktop

6- After copying the code and downloading the image, navigate to Desktop:

$ cd Desktop

7- Next, compile your code with g++ and add an extra statement to link the OpenCV library.

$ g++ LoadImage.cpp -o app `pkg-config --cflags --libs opencv`

8- Go ahead and run your program:

$ ./app

9- You should see the pixel values of the image displayed in the terminal and the Udacity image loaded in the display window.

10- If you wish to close the image and terminate the operation, press any key on your keyboard such as w.

OpenCV:

This is the official documentation of OpenCV where you can discover all the functions supported.