User manual
Version: v4.5.2
7.3 Information provided by the fusionTrack device
The fusionTrack is designed to provide accurate
relative
measurements, and should
not
be used to perform
abso-
lute
measurement. See Chapter 3 for more information.
Most of the functions of the
API
return a status code, which
indicates different levels of warnings and errors. The re-
turned code
must
be checked, the documentation is avail-
able in [1].
The various information retrieved from the fusionTrack for
each frame come with a status flag, which must
always
be
checked to ensure the integrity of the data.
The
API
is fully documented in [1]. In this section, the information which can be retrieved from the
fusionTrack when
markers
are tracked is shortly presented:
- The
marker
information, consisting of
–
the
marker
container status, indicating if an error occurred when retrieving the data;
–
the number of reconstructed
marker
, indicating the size of the container;
–
marker
3D position in mm;
–
marker
orientation (3x3 rotation matrix);
–
registration error in mm, corresponding to the result of the least-square minimisation between
the
marker
geometry and the measured
fiducial
positions;
–
the geometrical id, corresponding to the ‘id’ field from the geometry file Section 7.7;
–
a tracking id, giving a unique number to identify a
marker
on a frame;
–
a mask indicating which
fiducials
have been used to reconstruct the
marker
, i.e. if bit #
i
has
value 1, it means that
fiducial
#
i
was present;
–
the indices of the used
fiducials
, allowing to get the information about the used
fiducial
;
–
the
status
of the
marker
, which indicates whether the marker lies in the accuracy measurement
volume or not, consisting of the union of the statuses of all its
fiducials
;
- the
fiducial
information, consisting of
–
the
fiducial
container status, indicating if an error occurred when retrieving the data;
–
the number of reconstructed
fiducials
, indicating the size of the container;
–
fiducial
3D position in mm;
–
triangulation error in mm, corresponding to the error coming out of the triangulation algorithm,
i.e. the error on the
fiducial
position;
–
epipolar error in pixels;
–
fiducial
probability, indicating if a
raw data
was used to build multiple
fiducials
;
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