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Chapter 7. Experimental Validation - Agoraphobia
Figure 7.1: CAVE Setup. Left: CAVE viewed from outside. Right: A user testing the setup for
agoraphobia.
appreciation of users testing our system with head-tracking only and with the combination
of eye- and head-tracking. We also wanted to measure eye scan velocity and pupil dilation in
order to see if there would be any differences in eye contact behavior between the different
modes. Since stereographic display proved to be impossible whilst wearing the eye-tracking
device, we deactivated stereography for all participants.
In addition to the eye- and head-tracking, we use a glove in order to capture user gestures.
It is depicted in Figure 7.2. This glove has 8 LEDs on it which allow the retrieval of hand
position and orientation as well as an approximate position of the fingers. 8 optical cameras
are positioned around the upper edges of the CAVE in order to receive the signals from the
LEDs. The advantage of this system is that it presents much less drift than the magnetic type;
it does not suffer from the induced rotation around the sagittal axis.
Finally, we use a CAVE environment. As depicted in Figure 7.1, the CAVE consists of 4
screens: three walls and a floor. Its dimensions are 2.2 meters in length, 2.5 meters in width
and 1.8 meters in height. We use 4 projectors, one behind each wall, and one on the ceiling.
The scene is thus back-projected on the three walls and forward projected on the floor for a
very immersive environment. A more detailed description of the CAVE hardware setup can
be found in Peternier et al. [Peternier et al., 2007]. Additionally, a detailed description of the
software developed to display the scene seamlessly and with the correct perspectives with
respect to the user’s position can be found in van der Pol [van der Pol, 2009].
7.2 Participants
To validate our architecture, we asked 30 healthy participants to test it. Most of these participants
were from the academic world, as either students or researchers. All of them were
aged 20 to 60 years old with an average age of 35. Out of the 30 subjects, 22 were males and
8 females. They were not from any specific socio-economical background. 10 participants
tested the system with the combined eye- and head-tracking of which 8 males and 2 females.
The remaining 20 tested the setup with head-tracking only.
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