Survey of Pen-and-Paper Computing - Human-Computer Interaction - page 64

2.3 Directions of Future Research
This state of the art survey has shown that Pen-and-Paper Interfaces are technically
mature and have found their way into commercially successful applications. A wide
variety of technologies allow for capturing paper-based contents and for realizing
digital output on paper. A large number of interface concepts cover three main func-
tions of augmented paper with various paper media, ranging from tiny stickers over
books and printed documents to large paper posters. The survey has also shown that
a growing body of research aims at integrating paper more closely with real-time
visual output, resulting in augmented digital pens and in paper-digital interactive
surfaces.
To conclude this chapter, we briefly outline directions of future research on Pen-
and-Paper Computing. A more comprehensive discussion can be found at the end
of this topic in Chapter 8.2. While most previous work has focused on data input on
paper (output being provided on a separate computer screen), future work will aim
at further enhancing real-time feedback on paper . Livescribe has shown the direc-
tion that future pens are likely to follow further: include more powerful processors
to run complex applications directly on the pen and provide more real-time feed-
back on the pen. Future pens might feature larger displays, a built-in projector or
even a built-in inkjet printer to leave permanent marks on paper. Moreover, mobile
tracking-projection solutions are promising for transforming any paper document
into an interactive surface. The increasing processing power of mobile phones and
the advent of very small mobile projection units let us expect that in the near future,
every smart phone comprises the components that are required for paper-digital in-
teractive surfaces. A further, highly promising direction are flexible displays. These
combine many affordances of paper with the powerful capabilities of displays. It is
very likely that such displays will open up new and previously unforeseen ways of
interacting with digital information.
On the level of applications, we see five major challenges. The first challenge is
to fully leverage the mobile character of paper . Most prior applications either can-
not be used at all in mobile settings or only parts of their functionality are available
in a mobile setting. We expect more applications that couple paper and a digital pen
with a mobile phone. This coupling results in a powerful device federation that re-
quires only standard hardware which is already available today. Future work should
examine how the user interface can be repartitioned between pen-and-paper and the
mobile phone. A second challenge is related to how we manipulate paper in a Pen-
and-Paper User Interface. Powerful new tracking technologies allow for capturing
manipulations that deform paper , such as bending, folding and rolling. Future work
should examine these interactions more deeply.
A third challenge consists of improving large-scale collaboration . Most current
applications focus on a single user. In particular, it is still not fully understood how to
process, integrate and visualize paper-based contents that are created by a very large
community of users. This point is related to another challenge, the interpretation of
contents. Almost all current systems interpret pen-and-paper interactions only to a
very limited extent. The systems typically display only a facsimile of the handwrit-