5. Discussion
We presented a route planning, localisation and navigation system which integrates an indoor GIS of a
building with visual landmarks detected by a normal, hand-held camera. The system was designed such that it
can easily be integrated in the Blavigator prototype. The latter is already able to detect valid paths and any
obstacles in local navigation. The system presented here complements local navigation with global navigation,
although only indoor. The system works in real time on a netbook computer (Intel core i3, 1st series with 2GB
RAM) and it was tested successfully in the ISE/UAlg building. The performance time is on average 0.5s for the
localisation and 0.3s for the route planning.
The developed navigation framework offers robust localisation, even in cases where it is difficult to
differentiate regions on the basis of reference objects that are present. The navigation history enables autolocalisation,
by selecting the region that combines the largest number of nearby objects in the history.
However, the system supported in the estimated direction information to the next move (vector for
displacement). Localisation usually fails when the user deviates from the assumed or expected path. The correct
location is then restored as soon as sufficient navigation history (objects) or a single significant object exists.
False positive and negative detections may also interfere negatively. In the future a verification technique that
can rule out false detections by analysing the proximity relations with the other navigation history objects.
Nevertheless, most planned routes could be followed from the starting to the destination, even when these were
on different floors.
On-going work concerns including more landmarks in the database such that all spaces can be covered more
densely, and detecting doors and stairs from oblique viewing angles, such that the user can limit the pointing
angles of the camera to ±45º from the front. The final goal is a system which only employs a SmartPhone with
a built-in camera, worn by a strap around the neck.