Information Technology Reference
In-Depth Information
ware viewer. This version includes own and shared annotations, hyperlinks and tags.
To support both autonomous mobile use and real-time interaction with the system,
CoScribe offers two ways of synchronizing pen data with the digital system:
1.
Batch synchronization
: In order to retain the mobility which is inherent to pa-
per, the digital pen can be used autonomously. During writing on paper, data is
buffered on the pen. At regular intervals, the user synchronizes the pen with a
computer. All data temporarily buffered on the pen is then transferred to the digi-
tal system. Batch synchronization supports particularly well writing tasks, which
do not require immediate system feedback. However, no real-time interaction
with the digital system is possible.
2.
Real-time streaming:
If a computer is nearby, pen data can be sent in real-time
to the digital system over a wireless Bluetooth channel. This has the advantage
that all data can be immediately processed. For instance this is important for
providing real-time feedback when the pen is used as a stylus on a pen-enabled
display. However, the mobility of paper is restricted to an area within the range
of the wireless connection. With the current Bluetooth specification, this is up to
distances of about 100 metres. In the Bluetooth setup, up to 8 pens can simulta-
neously connect to one single client computer. This provides for co-located use.
If a larger number of pens is to be used, several client computers can be used in
the same place, which synchronize their data via the central database.
1
Once the pen data is transferred to the client computer, it is automatically handled
by a stroke processing module. This module checks whether the stroke originates
from paper or from the pen-enabled display and maps it to the associated digital
contents or interface elements. It then interprets the interaction and, if necessary,
executes a command. If the stroke is not a command but an inking interaction, indi-
vidual strokes are clustered into annotations.
Software Viewers
Changes made on a printed document are automatically in-
cluded in its digital version and made available in a software viewer. CoScribe
includes several viewers for different types of documents. Currently supported doc-
ument types are PDF and PowerPoint documents, Web pages and physical books.
For PDF and PowerPoint documents, CoScribe comprises an own document viewer
(Fig. 4.3). While we opted for a proprietary solution for our prototype, enabling
more flexibility during the iterative design process, future versions of CoScribe
could use plug-ins for standard software, such as Adobe Acrobat and Microsoft
PowerPoint. Web pages are available in Mozilla Firefox; a CoScribe Firefox plug-
in enables pen-based input on Web pages and displays additional information, such
as hyperlinks created by the user. A third viewer, the ecological view, integrates
all documents and displays them in a graph-based visualization (see Section 6.4).
The viewers can be used on standard computers. If the computer features an Anoto-
enabled display, they can be controlled with the same pen as used on paper. The
1
Note that currently only one Anoto Pen, Nokia SU-1B, allows for live switching between batch
and streaming mode. Other pens can be used only in one of the two modes. This is a technical
limitation of current pen models, not of our concept.
