Game Development Reference
In-Depth Information
Figure 11.16 Head-mounted display with CRT screens Datavisor 80, which is no longer available.
(Illustration: PSA Peugeot Citroën, with permission)
and were developed mainly for aeronautical applications. The head-mounted displays
using cathode screens were used but are no longer marketed as much (Figure 11.16).
11.3.3 Head-mounted displays with liquid crystal screens
The main advantage of the LCD screen head-mounted displays is generally their low
price, but this is often linked with a lower resolution on LCD screens. Some mod-
els nonetheless reach a resolution of 1280
1024 pixels per eye, as in the case of
AddVisor 150 from Saab Avionics, and 3200
×
1800 pixels per eye in piSight by
Sensics (Figure 11.18). The latter has 12 mini-screens for each eye, assembled in a
4
×
1800 pixels. The visual field is 140 degrees horizontally
with a stereoscopic overlap of 70 degrees.
The structure of these head-mounted displays is identical to that of cathode
screen head-mounted displays, except for the two screens and two diffusers used for
de-pixelizing (Figure 11.17).
×
3 matrix providing 3200
×
11.3.4 Optical model of a head-mounted
display and related problems
11.3.4.1 Problems in the visual quality of a head-mounted display
One of the major difficulties of head-mounted displays is making it possible to observe
the images on screens that are very close to the eyes, and for this we need to insert
optics between the eyes and the screens. It is necessary to fully determine the geometry
and the optics of the head-mounted display to be able to calculate and display the
stereoscopic images correctly on the two LCD or cathode screens. If we move the
head, a fixed object is seen from different angles and the dimensions of its images on
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