Head-mounted Display - Peripherals

Peripherals

• The most rudimentary HMDs simply project an image or symbology on a wearer’s visor or reticle. The image is not slaved to the real world (i.e., the image does not change based on the wearer’s head position).
• More sophisticated HMDs incorporate a positioning system that tracks the wearer’s head position and angle, so that the picture or symbology displayed is congruent with the outside world using see-through imagery.
• Head tracking – Slaving the imagery. Head-mounted displays may also be used with tracking sensors that allow changes of angle and orientation to be recorded. When such data is available in the system computer, it can be used to generate the appropriate computer-generated imagery (CGI) for the angle-of-look at the particular time. This allows the user to "look around" a virtual reality environment simply by moving the head without the need for a separate controller to change the angle of the imagery. In radio-based systems (compared to wires), the wearer may move about within the tracking limits of the system.
• Eye tracking – Eye trackers measure the point of gaze, allowing a computer to sense where the user is looking. This information is useful in a variety of contexts such as user interface navigation : by sensing the user's gaze, a computer can change the information displayed on a screen, bring additional details to attention, etc.
• Hand tracking - tracking hand movement from the perspective of the HMD allows natural interaction with content and a convenient game-play mechanism