Question

Sometimes it is beneficial to actually display some information overlaid on the video sequence when doing video processing with OpenCV. Is it possible to do this? How might that be done?

Answer 1

There is a function cv::putText which can be used to draw text into an image. So just grab the image from the video and draw the text on top of it before showing it. There should also be a similar function in the OpenCV C-API, but since you tagged it C++ I assume you use the C++ API, anyway.

EDIT: Of course this function modifies the image, which then also contains the drawn text. So if you still need the original image for further processing, you should use cv::displayOverlay. This might actually be a better solution than cv::putText, since it is a bit easier to use and is intended exactly for showing some small information over an image in a highgui window.