Learn how to load, display and output images of OpenCV notes to files

Loading, displaying and outputting images to files

OpenCV namespace

C++ classes and functions in OpenCV are defined within the namespace cv.

Image loading: imread() function

prototype:

Mat imread(const string& filename, int flags = 1);

• filename : image name
• flags : Load flag, specifying the color type of a loaded image
  CV_LOAD_IMAGE_GRAYSCALE - 0: Convert the image to grayscale and then return
  CV_LOAD_IMAGE_COLOR - 1: Default value, color image

Image display: imshow() function

void imshow(const string& winname, InputArray mat);

• winname : The name of the window identification that needs to be displayed

Create window: namedWindow() function

void namedWindow(const string& winname, int flags = WINDOW_AUTOSIZE);

• WINDOW_AUTOSIZE : The window size is automatically adjusted to fit the displayed image. Users cannot manually change the window size.
• WINDOW_NORMAL : window size can be changed by the user
• WINDOW_OPENGL : The window supports OpenGL

Delete window:

destroyWindow(const string & winname);
destroyAllWindows();