
User manual
Version: v4.5.2
11.2
Control marker registration and epipolar errors
At any time, the marker registration error and the marker
epipolar error (defined in Section 7.8) computed by the
SDK
must be monitored. The integrator must define thresholds
above which the errors can lead to unacceptable risk for the
patient. If the errors go above the aforementioned thresh-
olds, the integrator must prevent the user from accessing
the data.
A large epipolar error affecting all fiducials can be caused by
the fusionTrack operating outside its temperature range or
being decalibrated.
A large registration error can be caused by the orientation of
the
marker
: e.g. if the
marker
becomes close to parallel to
the optical axis. The integrator shall generate an error mes-
sage if the orientation goes above a defined angular thresh-
old.
A large registration error can be caused by an object in the
field of view which occludes partially the marker. The inte-
grator shall state in their user manual that no objects in the
field of view are allowed but the
markers
, pointers or surgical
tools.
A large registration error can be caused by a scratched fidu-
cial, liquids on fiducial, damaged fiducial, wrongly fixed fidu-
cials on the marker, or a deformed marker. The integrator
must generate an error message when the marker registra-
tion error is too high.
11.3
Control fusionTrack temperature
The integrator shall monitor temperature sensors. If the
measured temperatures diverge from the reference temper-
atures, the data shall not be given to the end-user.
The fusionTrack device is operational after warm up. If used too early, during thermal expansion, this
could lead to wrong measurements. The most accurate measurements are obtained when the temperature
of the fusionTrack corresponds to its calibration temperature. The
SDK
allows to access the fusionTrack
device temperature sensors. This is explained in details in the
ftk8_GetTemperatures
sample, whose code
and binaries are available in the
SDK
installer / tarball. The calibration temperature is reached after approx-
imately 40 min for a room temperature of 20 °C.
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