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ABSTRACT
In this paper we describe the technical part of the Digital
Jewellery project at the Institute for Geoinformatics
Münster, Germany. This project takes place during
summer term 2007. The two main parts are a video player
containing a bluetooth scanner running on our iDisplays
and several digital jewellery created by Jayne Wallace and
Patrick Olivier at the Culture Lab Newcastle of the
University of Newcastle. This text focuses on the software
part, not the digital jewellery part.
INTRODUCTION
During the last years, large displays have been getting
cheaper and cheaper. So more and more large displays are
placed into the environment. The Digital Jewellery project
tries to establish a more personal connection between
people and these displays. Normally, only impersonal
informations are shown on displays, like news, timetables
or commercials. But these displays could also be used for
showing some more of „you“. Our idea is to create some
digitial jewellery what will be recognized by displays and
show some personal information about you. In case you
think, personal information are only your name, your
address, your birthday, your mobile phone number, etc.,
you're wrong! How about showing some holiday photos or
movie clips? Or movies from your work or hobbies? Or a
movie clip you've just taken on your way to work? Maybe
it would be cool to show to your friends or colleagues or
just any person walking by the displays with you. We try
to find out how you and the environment will react to this.
TEST SETUP
Technical requirements
Currently six iDisplays are running 24h at the Institute for
Geoinformatic. They are placed at both entrances of the
institute and evenly spreaded at the office corridors, so
every IfGI member walks by at least one iDisplay on his
way to his office or lecture room. During a normal day,
everybody will walk by more than one display. This is necessary because our iDisplay are a major part of the test
setup. The digital jewellery is created individually for
every person based upon the video clips they recorded. The
jewellery are invented by Jayne Wallace and Patrick
Olivier at the Culture Lab Newcastle.
A bluetooth scanner software has been developed during
the project “Interaction with public displays” at the IfGI in
summer term 2006. The code will be re-used and adjusted
to the needs of the Digital Jewellery project. Additionally a
video player software will be developed using Java and
coupled with the bluetooth scanner.
The software will run on the iDisplays and scans enduring
its environment for the digital jewellery. If any digital
jewellery is found, a video clip will be loaded and shown
on the iDisplays.
The software will run 24h a day during the evaluation
period.
General conditions
The evaluation of the whole project will take place during
august and September 2007. Because of the focus of this
paper on the technical part of the project, the result of the
evaluation will be available in another paper. The four
selected participants are a professor, an institute employee,
a PhD student and a Graduate student, so there is no
problem because of the evaluation period isn't located
directly in the summer term.
TEST PROCEDURE
Technical part
During the last projects using bluetooth in any way, the
open source java bluetooth implementation BlueCove has
proved its vantages. The major disadvantage of BlueCove,
the missing Linux implementation and the only usage of
the Microsoft bluetooth stack, can be left out of focus
because all of the iDisplay systems are running Windows
XP SP2. The used video clips from the participants are
located on (different) webservers so that the video player
is able to load them on demand and video clips can be
exchanged without the need of changing anything on the
iDisplays directly. Any configuration needed for the
project and all of the produced information for the
evaluation is stored in a central database.
Bluetooth scanner
The iDisplays need to know if any of the participants
wearing the digital jewellery are in range. Face recognition
is no alternative because of privacy aspects and the
problem, that participants should be recognized “walking
by” without the need for standing directly in front of a
camera. A bluetooth scanner has been developed during
the “Location Based Services” seminar by the project
“Interaction with public displays”. The scanner source was
already used by different projects and has proved its
vantages, so it will be re-used also for this project here.
The bluetooth scanner works in a passive way without the
need of any software saved or running on the client
bluetooth devices. There is just no alternative to this
because the digital jewellery only contains a bluetooth
device without an operating system around it like a mobile
phone has.
A continuous scan must be guaranteed. Our bluetooth
scanner looks for the digital jewellery available in range
and commits this information to the video player part of
the software. A major problem is the definition of “range”
in this context. Bluetooth is working invisible, so not only
bluetooth devices in front of the iDisplays running the
bluetooth scanner are recognized, also devices located in
offices or even on another floor are recognized. Also lots
of devices and mainly humans are disrupting the range. For
example, a single person wearing the digital jewellery
walking down the corridor is recognized by the scanner
within a range of 10 or more meters. If a group of humans
is walking through the corridor, the person wearing the
digital jewellery is first recognized within a range of 2 or 3
meters. These problems are well known and a solution
hasn't been found yet.
The duration of a bluetooth scan is about 11 seconds. After
these 11 seconds, all of the found bluetooth devices are
presented by the scanner, not during the scan. This is a
problem of the Windows bluetooth implementation, as far
as we know, so this has to be taken as it is. During other
projects using this bluetooth scanner, it has been
discovered, that it's dependent on the bluetooth device,
when this device is found by the scanner. Some devices
have to be “visible” during the whole scan duration, others
just have to be “visible” for some seconds or just a piece of
a second. So some devices are recognized better than
others. All of the digital jewellery pieces contain the same
bluetooth technology, so it can be adopted that they will be
act in a same way with the scanner producing alike results.
After a bluetooth scan has finished, the gathered
information is committed to the video player and the next
scan is started. If the video player decides to show a video
clip, the bluetooth scan will be paused. The reason for that and more information can be found in the next part of this
paper.
Video player
The video player is the second major part of the software.
In general, Java and multimedia are two things that don't
consort very much. A proof for that is the Java Media
Framework (JMF). It's latest achievement is the mp3
support. And this achievement has been introduced in
November 2004! So there is a problem to deal with
because the JMF doesn't know anything about modern
video codecs like MPEG-4, DivX or XviD. There are
several further (open source) project based upon the old
JMF but nearly all of them are in a early beta or almost
alpha stadium and not adapted for this project.
One project however, looked very interesting because it
has its beginnings in 2004 and is based upon FFMpeg, a
wide spread open source codec library with support of
nearly all common used video and audio codecs. The name
of this project is FOBS. This project is still active and the
latest version of the software has been released in January
2007. Another great advantage is that FOBS places itself
between the old JMF and FFMpeg. So JMF can be used for
developing and all encoding is done by FFMpeg. No
installation of FFMpeg on the system is required, which
reduces the administration complexity on the iDisplay
systems.
Our idea is, that the video player will hide itself in the
background if its unused. It will get in front of all
applications if a video clip is shown. Information about
that is gathered by the bluetooth scanner; see section
“Bluetooth Scanner” for more information about that. The
video clip will be shown in a full screen mode without any
borders around it. So the full attention of people walking
by or standing in front of the iDisplays could be
guaranteed. Video is the only possibility to get the
attention because the PC hardware of the iDisplays is
normally not directly placed in range of the display and an
audio connection between the PC hardware and the
iDisplay isn't available everywhere.
Database
A PostgreSQL database is used to store information about
the participants, the participants video clips and log entries
for evaluation purposes. The following data is saved in
three different tables.
1. Participants: Name, eMail address, bluetooth address of
the the weared digital jewellery
2. Participants video clips: Number, URL, owner, length
3. Logs: Number, participant, video, time stamp, iDisplay name
The fields of tables one and two are clearly. If a video clip
is shown, the owner of this video clip, the time stamp and
the name of the iDisplay, where the video clip has just
been shown, are saved to the log table. This information is
required for the evaluation of the project.
Digital Jewellery
The digital jewellery will contain a small bluetooth device.
What exactly isn't know yet because the devices are still
under development. The requirements are that the device
will operate continuously, without any external input and
will be “visible”. In this combination, “visible” means that
it will be visible to the bluetooth scanner, like any
bluetooth mouse or headset. Higher bluetooth devices can
be set to an invisible mode that will hide them from the
bluetooth scanner.