Biomedical Engineering Reference
In-Depth Information
[27] allows for a tiled-display environment to also act as a distributed com-
puter. In this approach, the same application is started on the tiled-display
environment as well as the head node. The viewpoint is changed on each ren-
dering node to match the overall tiled-display view with that of the head node.
All user events such as key presses and mouse movements as well as graphical
events such as buffer swaps are synchronized. The advantage of this approach
is that it requires very little network bandwidth in order to operate and has
the ability to scale well beyond the other approaches mentioned. Furthermore,
this approach allows for computation to be distributed throughout the display
environment and for graphic card shaders to run natively. The disadvantage
of this approach is that code must be compiled for the tiled-display environ-
ment. Furthermore, each node needs to have access to the data to be rendered,
either by distributing it to the render nodes beforehand or through a network
fi le system or data stream.
27.2.3
Multitouch - Enabled Environments
While multitouch technology has only recently been adopted for consumer
applications, the history of multitouch research has spanned multiple decades.
In 1984, Lee wrote his master's thesis [28] on the use of multitouch and a year
later continued his work with Buxton and Smith [29]. Unfortunately, while the
interface technology was being developed, the computation power needed for
its practical implementation was still lacking. In 2001, Westerman et al. pub-
lished a paper on human-computer interaction discussing how multitouch
could be used as an intuitive computer interface [30]. Later that year,
DiamondTouch, a multiuser touch system was produced [31]. In 2004, Han [32]
and Wilson [33] created signifi cant interest in this technology, following their
presentation of more accessible approaches to multitouch technology.
Subsequently, Smith et al. [34] proposed creating low-cost pressure-sensitive
surfaces in 2007. Today, multitouch devices are pervasively available and
used and represent a unique interface for collaborative visual analytics
environments.
27.2.4
Multiuser Interaction Techniques for Large - Display Environments
Several approaches have been developed for multiuser interactions in large-
display environments and stress different types of modalities and metaphors.
“Fluid Interaction with High-Resolution Wall-size Displays,” by Frangois et al.,
showed how a pen interface could be useful for interfacing with display walls
[35] and enabled user identifi cation through handwriting analysis. “LumiPoint:
Multi-User Laser-Based Interaction on Large Tiled Displays,” by James Davis
and Xing Chen, examined techniques for enabling multiuser interaction
through laser pointers [36]. Laser pointer position and velocity were tracked
through a central server and multiuser support enabled by adding laser point-
ers of differing colors. This approach was found to be scalable by adding
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