how to use boundary box algorithm for people tracking in GUI

this is my final year project about people tracking in video sequence using GUI.for the Gui.fig, i display 4 axes and have their on push buttons but I'm stuck with the last step to create the rectangle over their head using bounding box(the algorithm method that i used).so, can anyone help me with this method?and how can i create the bounding box frame by frame?

waiting...thank for the helps.