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  > **Note**

  This function should be followed by cv::waitKey function which displays the image for specified milliseconds. Otherwise, it won't display the image. For example, **waitKey(0)** will display the window infinitely until any keypress (it is suitable for image display). **waitKey(25)** will display a frame for 25 ms, after which display will be automatically closed. (If you put it in a loop to read videos, it will display the video frame-by-frame)