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The circuitry in this rangefinder reports ``floaters'' around specular
items. The floating points tend to occur alone and can be removed
with the following rule: a valid reading must be near at least one of
its neighbors. This assumes that most of the data is valid, which it
is. The floaters can be eliminated or replaced with a copy of a
neighbor's position. We are also exploring estimations, since the
environments scanned contain so many planar surfaces.
Another source of errors are specular objects, at the positions where
the laser is reflected directly back on itself. The measurement for
the highlights is closer than the surrounding area, thus the bright
spots seem to hover off of the surface. While these errors have not
been explored in great detail, it is our opinion that they stem from
the strength of the signal returned, and can be compensated for.
Lars S. Nyland
1999-02-19