Chapter 4
4.8 Setting up the cameras
Z
The point cloud should fill at least two thirds of the measurement vol-
ume. Moving the wand in a restricted volume will result in reduced
accuracy of calibration or failure.
If in a system setup no sufficient part of the measurement volume is seen by all IR cam-
eras simultaneously, the point cloud created by the wand movement has to connect all
cameras in a way that ensures the arrangement of all cameras in a common room coordi-
nate system. This means cameras that see the calibration angle are oriented first. Then
every additional camera has to be connected by a sufficient volume with at least two al-
ready oriented cameras. In this way, the calibration is stepping forward from camera to
camera. (e.g.: cameras 1 and 2 are seeing the angle - camera 3 overviews a certain
volume together with cameras 1 and 2 - camera 4, finally overviews a volume together
with cameras 1 and 3).
Calibrating cameras which do not observe the angle directly is called "chain calibration".
Chain calibrated cameras propagate inaccuracies from the previously calibrated cameras.
It is recommended to place the calibration angle in a point where as many cameras as
possible can see the angle.
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