![](bg7.png)
lines. In Figure 8 the collaborative work on such
seismic lines is shown for two users including the
depth image.
Figure 8: Left: Two users working on the same seismic
line. Right: According depth image.
From the above mentioned functionality we
implemented input coordination and individual tool
selection (see Figure 7). From our earlier
experiences with the test applications we expected
that technologically unaware users would not even
realize that they are tracked to ensure fluid multi-
user multi-touch interaction.
Experts from geology were using our context-
aware multi-touch system and we received very
positive feedback. Also the display size, its
impressive image quality with ultra-high resolution
and the accuracy of the multi-touch input were
highly appreciated. With the expectation of
becoming frequent users of the system our visitors
were delighted about the adaptation features of the
assembly, which easily allow changing the height
and inclination of the display. As expected, most of
these experts did not realize the implicit input
coordination to be an obvious feature. The system
just worked as expected.
5 CONCLUSIONS
We analyzed state-of-the-art methods to achieve
user awareness of multi-touch tabletop displays and
derived an improved method from our experiments.
Based on the sensor data from a depth camera we
achieved robust context tracking. We described an
implementation of this method including automatic
re-calibration, sensor-fused segmentation, separation
of users, robust hand identification based on
geodesic distances and a detection method for
involuntary touches. Based on the resulting user
awareness, we suggested interaction techniques for
fluent co-located collaboration. While the general
idea of context tracking with an overhead camera
has been proposed earlier, we contribute a detailed
description of a timely method that is robust and
easy to implement. Finally, we described a high-
fidelity system prototype and a collaborative
application for the exploration and interpretation of
seismic data.
We are looking forward to gain further insights
on the usability of the system in long-term studies
with expert users.
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