Information Technology Reference
In-Depth Information
2.2.5 Augmented Tables, Flipcharts and Whiteboards
Augmented tables, flipcharts and whiteboards combine paper-based media with in-
teractive tabletop and wall displays. They provide a close integration of paper and
digital media by combining them on one single surface. Paper documents can be
used directly on top or in front of a large computer display. Alternatively, or in
addition, digital information is displayed directly on paper.
Above we have already reviewed some concepts to display digital information
in-situ, within a paper document, e.g. by leveraging mobile projectors or superim-
posed PDA displays. However, digital information was restricted to a small surface.
In contrast, augmented tables, flipcharts and whiteboards realize very large digital
display surfaces. These systems combine many of the augmented paper principles
that we have introduced above.
Early works on augmented desks date back many decades. Already in 1945, Van-
nevar Bush envisioned
Memex
[12], an augmented desk that is able to display virtual
documents on the table surface. Memex was thought of as an electro-mechanical
machine that stores all books and other documents of a user on microfilm. Memex
enables the user to read and annotate these documents as well as to create asso-
ciations (we would call them hyperlinks today) between these documents. Memex
never went beyond a theoretical state; however, it strongly influenced the develop-
ment of hypertext systems and of augmented desks.
The foundations of digital augmented desks and tables, and of paper-based com-
puting in general, were laid in a series of seminal works at EuroPARC in the early
1990s. A highly influential system is Wellner's
DigitalDesk
[167]. As shown in
Fig. 2.21, the user can place printed documents on the table, very much like on a
traditional desk. In addition, digital documents are projected onto the desk surface,
and printed documents can be overlaid with projected information. This creates a
very seamless integration of physical and digital contents.
The combined tracking and projection setup of the DigitalDesk inspired many
follow-up works. It is depicted in Fig. 2.21 (left). A camera is mounted at a fix
position above the desk. By analyzing the stream of images captured by this camera,
the system identifies the position and the contents of printed documents. Moreover,
the camera images are used for detecting pen and touch input on the desk - both on
paper documents and on projected contents. Similar to the camera, the projector is
mounted at a fix location above the desk.
Several example applications of the DigitalDesk introduced a set of novel interac-
tion techniques. One interaction allows for physical-digital copy&paste of data. In a
calculator application (Fig. 2.21 right), the user can copy numbers from printed doc-
uments by pointing on them. For recognizing numbers within the document snap-
shot captured by the camera, optical character recognition is used. Another interac-
tion realizes physical-digital copy&paste of images. The user can draw a sketch on a
sheet of paper and copy this sketch to a digital collage using a simple gesture. In the
background, the system extracts an image of the sketch from the camera snapshot
and projects this as a part of the collage. An extension of the initial system [124]
in addition allows users to follow hyperlinks on printed versions of Web pages. By
