Image to probe transform calibration error too high - spatial calibration

[NesBarn]

To get an orthogonal matrix during automatic spatial calibration, I enforced orthogonality by specifying optimizationMethod and IsotropicPixelSpacing. The problem is that I always get the message "Calibration error is too high" even when the probe (on which is mounted the tracker tool) is fixed and doesn't move... I don't know from where comes the problem (error of 0.41mm during Phantom registration and 0.35 mm during pivot calibration). For information, if it may help, I needed to set "PortUsImageOrientation="UF" in order to obtain the right pattern of the wires (see image attached) (because if the probe is fixed with its marker in front of the "M" over the phantom and the "PortUsImageOrientation" set to "UF", I have the wrong pattern (wires flipped)