Multi Level Surface Mapping using Sparse Point Clouds - Student ...

Chapter 6. Result discussion 32
quadrotors width by analyzing the map. In this Birmensdorf set, the quadrotor
seems to be 0.15 wide - about the same size as the cells in the surface map. With
maxGap set to 0.15, the hole plastering algorithm will therefore only close gaps of
one cell size width. Now to still get a good feeling of how the environment looks
like, the maxGapEnhanced parameter is set to 0.75 to also close gaps which are up
to 5 cell sizes wide. This final result is shown in image 6.3.
Figure 6.2: Surface map of Birmensdorf set with partial hole plastering
Figure 6.3: Surface map of Birmensdorf set with all optimizations, viewed from two
different perspectives
In this final result we can see a lot of red points. Those points mark the surface
patches, which were additionally inserted by the hole plastering algorithm since the
last shown MLS map output. So all these patches were used to plaster holes and
gaps which were larger than 0.15 and smaller equal 0.75. In the MLS framework,
these surface patches are also marked for later use with a flag called FlagArtifical.
With this marking we can always keep track of areas which were inserted unjustly.
It’s possible, that those really are closed areas, but they could also be open. And
based on the fact, that these closed gaps were larger than the quadrotor, it would