Head-up displays, commonly referred to as HUDs, are devices used to superimpose data over the field of view of a vehicle operator. This allows the user to maintain his or her focus on controlling the vehicle according to the environment, while also being fed operational data about the vehicle, such as speed, direction, and navigation. In aerospace applications, HUDs display altitude, flight paths, weapon systems, as well as a variety of essential flight info. Some automobile applications utilize HUDs to provide drivers with traffic information and engine reports as well. HUDs consist of: a projector unit to create a visual display of the data; a transparent combiner on which the projector displays its imaging; and a video generation computer, which assembles operational data and feeds it to the projector. HUDs are either dash or helmet-mounted.