Once the data components were in place, I set about creating a graphical user interface to The GUI consists of an area where the video image of the subject along with the user-draggable and user-resizable region of interest, or roi, can be seen; an area where the real-time signal from the webcam and the real-time heart rate, hr, can be seen; and an area where the real-time signal and heart rate from the pulse sensor can be seen.