1. A method of controlling a presentation on a computer-based presentation device by using a processing unit to recognize gestures within a video stream captured by a video camera connected to the processing unit comprising the steps of: performing a skin-recognition within a screen of the video stream for recognizing skin parts; identifying at least a face and a hand within the recognized skin parts; identifying a center point of the face and hand; defining at least one screen area by an angular position with respect to the center point of the face; monitoring a state of the at least one screen area; generating a control signal indicating a detected gesture upon detection of the entry of a hand into the at least one screen area; and inputting the control signal to the computer-based presentation device to control the presentation.