December 2012
Intermediate to advanced
340 pages
8h 3m
English
Content preview from Mastering OpenCV with Practical Computer Vision ProjectsBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Main camera processing loop for a desktop app
If you
want to display a GUI window on the screen using OpenCV, you call cv::imshow() 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 indefinitely 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 main_desktop.cpp, as the basis for 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; exit(1); } // Create a blank output image, that we will ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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