Inside the Trimble X9: Deep Dive into Trimble X9 Auto-Calibration 10
Infigure6,weshowthemodifiedschematicoftheEDMwhereacopyoftheemittedlaserpulseis
sentthroughacalibrationline.
Figure 6: Schematic of EDM with calibration line
Thiscalibrationlinehasanextremelystablecalibratedreferencedistanceandhasabuilt-in
VariableOpticalAttenuator(VOA),whichallowsustomodifythepulsesignallevel.Beforeeach
scanisinitiated,wemeasurethedistancegivenbypulsespassingthroughthecalibrationlineforall
possiblesignallevels.Theresultofsuchacalibrationisshowninfigure7.
Figure 7: Distance correction look-up table
Asweknowthephysicalreferencedistanceofthecalibrationline,weknowthedistanceoffset
correctionthatmustbeappliedforadistancemeasuredwithagivensignallevel.Therefore,when
wecarryouta3Dscan,foreachdistancemeasured,weusethepulsesignalleveltoapplya
distancecorrectionaccordingtothelook-uptablegivenbyfigure7.
Thankstothisinnovativeapproach,X9userscanhaveconfidencethateveryscaninallconditions
willgivethemthequalitydatathattheyexpect.
