ABSTRACT
Head-mounted displays (HMD)* are personal information-viewing devices mounted on the head that can provide information in a way that no other display can. The information is always projected into the user’s eyes, and it can be made reactive to head and body movements, replicating the way we view, navigate, and explore the world. This unique capability lends itself to the following applications:
• Virtual reality for creating artificial environments1
• Medical visualization as an aid in surgical procedures2,3
• Military vehicles for viewing sensor imagery4
• Airborne workstation applications, reducing size, weight, and power over conventional displays5
• Aircraft simulation and training6,7,8
• Fixed and rotary wing avionics display applications, as explored in this chapter9,10
In some applications, such as the medical and soldier’s displays in Figure 5.1, the HMD is used solely as a hands-off information source for viewing endoscopic video, text, maps or graphics. But to truly reap the benefits of the HMD as part of an avionics application it must be part of a visually coupled system (VCS), which includes the HMD, a head position and orientation tracker, and a graphics engine or video source.11,12 As the pilot turns his or her head, the tracker relays the orientation data to the mission computer, which updates the displayed information accordingly. This gives the pilot access to a myriad of real-time data that is linked to head orientation. In a fixed-wing fighter, a missile’s sensor can be slaved to the line-of-sight from the pilot’s head, allowing the pilot to designate targets away from the forward line-of-sight of the aircraft. In a helicopter, the pilot can point sensors such as forward-looking infrared (FLIR)** and fly at night. Because the aircraft mission computer knows the pilot’s head orientation, the
HMD can also display real-time data that are either aircraft-or earth-referenced, such as runways, threats, friendly aircraft, and horizon lines.
