Biomedical Engineering Reference
In-Depth Information
Fig. 11.10
An example of a
user's path (
the wiggly blue
lines
) through a virtual and
real space. The virtual space
is represented by the
solid
box
and the real space is
denoted by the
dashed box
.
The
dashed box
shows relative
size of real and virtual spaces.
(Reproduced from Peck et al.
[
23
])
With reorientation and/or redirection, the paths in the virtual and real world have
different shapes and, as is the goal, the real world path covers less area than the
virtual. Figure
11.10
shows an example.
Peck et al. introduced
distractors
which are visual objects or sounds in the virtual
scene used to stop the user and elicit head rotations. Devoting attention to distractors
appears to make people less aware of scene rotation while they are turning their heads
[
20
,
24
]. Distractors have been used in conjunction with redirection [
21
,
22
], and
users of the combined system scored significantly higher on a variety of navigation
metrics than users of walking-in-place and joystick interfaces.
The locomotion interface implemented by Neth et al. used avatars as distractors,
and when combined with their implementation of dynamic curvature gain, enabled
people to successfully explore a large virtual city [
18
].
Alternatives to distractors include
deterrents
[
22
] and
Magic Barrier Tape
[
6
]. Both
techniques display a virtual barrier to mark the real boundaries of the tracked space.
The implementation fromCirio et al. uses a joystick method to move the unreachable
portions of the virtual scene into the tracked space [
6
], whereas the implementation
by Peck et al. uses distractors and redirection to rotate the unreachable part of the
scene back into the tracked space [
22
].
