HMD's are strongly associated with VR and more recently are being
applied to augmented reality applications whereby computer-generated
images are super-imposed onto the real world. The most important
features to look at on an HMD for VR/AR are:
- Resolution
- Field-of-view (FOV)
- Usage
- Tracking options
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eMagin Z800 3DVisor: an immersive
3D computing experience
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Some
of Inition's most popular HMD's for VR and AR:
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Icuiti DV920 |
All-digital Video Eyewear system with progressive-scan capabilities
and an automatic scaling engine.
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Resolution
Typical HMD's have a resolution of 800 x 600 resolution (SVGA)
but vary from 320 x 240 (qVGA) up to 1700 x 1350. For viewing
a standard windows desktop or application, 800 x 600 is normally
adequate. |
Field of view (FOV)
This figure is used to measure how much of the user's field of view
the image takes up. Average human vision covers an area of about 200
degrees horizontally by 150 degrees vertically. Headset FOV figures
are typically given as diagonal FOV. That is the perceived angle from
one corner of the screen to the opposite corner.
 |
 |
Approx. human
vertical field-of-view |
Approx. human
horizontal field-of-view |
Typical figures for HMD's diagonal FOV's
range from 26 degrees to over 100 degrees for high-end military models.
The higher the FOV, the more immersive the imagery will be. One disadvantage
of high FOV displays is that they appear lower resolution because the
pixels are spread over a greater viewing area. Take a look at our HMD
comparison table for a full list of FOV's of all our head-mounted displays.
Usage
HMD's are often required for public display usage (museums,
shows, etc.) and models have been designed specifically with
this purpose in mind. These models feature toughened cases,
strengthened cabling, and shock absorption designed to withstand
the wear and tear associated with daily public usage.
As mentioned previously, another emerging use of HMD's is for
displaying information to workers on site locations such as
power stations, airports and events. A new breed of monocular
head-up displays cater for this application. These displays
are so discreet that they are being used for providing information
to security and police forces. Please read the monocular
HMDs guide for more information on these devices.
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Icuiti DV920: all-digital 640x480 (VGA)
native
resolution Video Eyewear system |
Tracking
When using an HMD for virtual reality, is it necessary to track the
orientation of the user's head in order to let the
user look around the virtual world. It is sometimes also desirable to
track the user's x,y,z head position in order that
any changes are reflected by a new view on the virtual world. There
are many different tracking technologies suitable for this purpose,
including magnetic based systems such as the Ascension
Flock of Birds and inertial systems such as the Intersense
InertiaCube . Some of these tracking products can be extended to
include tracking a user's hand for interacting with objects in the virtual
world. To see Inition's full range of tracking devices, click
here.
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A
comprehensive comparison table of Inition's
Binocular HMDs |
If you are want to
find out more about virtual and augmented reality we recommend a visit
to our central London demo suite. Please get in touch to arrange an
appointment. +44 (0)20 7613 5004. inition@inition.co.uk
Head
Mounted Displays 
