User`s guide

3 Aims
The video wall is currently on 24 hours a day, so that people can walk up to the wall, see if anyone
is in the room and start a conversation with anyone on the other side of the wall. This is arguably
its best feature in terms of usability. It is almost a standard setup, the only modification being an
infra-red motion detector that turns off the projector if no movement has occurred in the room for
a number of minutes, and turns it on again as soon as motion is detected. This was installed to save
on electricity costs.
A schematic diagram showing the setup of the current CSSE videoconferencing system is shown
in Figure 2. Not included on this diagram are the infra-red motion detectors, which are attached to
the projectors.
Figure 2: Diagram of current CSSE videoconferencing system
The current system can be made much more user friendly, as well as reducing costs further.
The following improvements to the system would also make the video wall not just a simple video
communication device, but a powerful tool for conversations, meetings and seminars.
• Video reciprocity. The current system whereby the projector is switched off when the room
is empty can be extended so that both projectors are switched off. Such a system would also
enable the ATM link to be shut down and start up when necessary. Currently, the ATM link
is constantly up. Shutting down the link when its not in use would save on costs.
This system also addresses the privacy concern of reciprocity. As mentioned in Section 2.2,
previous research has shown that people are concerned by the prospect of being visible to
someone without the reverse being true. For example, someone could be out of the camera’s
field of view, but still be viewing the video wall (see Figure 3). With the current camera and
projector, it is impossible to eliminate the “viewer’s field of view only” region, but it has been
found that the infra-red motion detector can detect motion at a wide angle, which makes it
suitable for the purposes of the proposed system.
A proposed system is to design an application which would gather the state of both motion
detectors (on or off), take the logical “and” of both states, and pass the result back to both
VANs (see Figure 4). Each VAN would then decide whether to start up or shut down the ATM
link, and also turn on or off the local projector.
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