Building Computer Vision Projects with OpenCV 4 and C++

Main camera processing loop for a desktop app

If you want to display a GUI window on the screen using OpenCV, you call the cv::namedWindow() function and then the cv::imshow() function for each image, but you must also call cv::waitKey() once per frame, otherwise your windows will not update at all! Calling cv::waitKey(0) waits forever until the user hits a key in the window, but a positive number such as waitKey(20) or higher will wait for at least that many milliseconds.

Put this main loop in the main.cpp file, as the basis of your real-time camera app:

while (true) {     // Grab the next camera frame.     cv::Mat cameraFrame;     camera >> cameraFrame;     if (cameraFrame.empty()) {         std::cerr<<"ERROR: Couldn't grab a camera frame."<<  std::endl; ...