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Towardholographic-guidedsurgery1076Figure1MicrosoftHoloLenswithframeUsingthereflectivemarkersontheframethepositionoftheHoloLenswastrackedbytheopticaltrackerTECHNICALBACKGROUNDOpticalTrackingSystemForobjecttrackingthePSTBasesystem(PS-TechAmsterdam TheNetherlands)wasused ThePSTBasesystemisaninfrared-basedopticaldualcameratrackerthattracksthepositionandorientationofobjectsinrelationtoafixedreferencewiththeuseofreflectivemarkersphereswithadiameter of13mm Thepositions of thesemarkers were correlated withmarkers onthe virtualobjects ThePST trackingsystemhadarootmeansquareerror<05mmand<1° The fieldof viewof thePST tracker wascone-shaped andhas arange from20to300cm29UsingthePSTclientsoftwaretherecognitionofdifferentobjectswas trainedbycreatingauniqueconfigurationof 4ormorereflectivespheres Thepositionandorientationoftheseobjectsweretrackedwithafrequencyof120Hzandalatencyof15to25ms ThetrackinginformationwasimportedinUnitysoftware(v560UnityTechnologiesSanFranciscoCAUSA)Three-dimensionalmodelsof the virtualplanning wereimportedinUnityusing thestereolithographyformatandlinkedtothetrackedpositionandorientationofthephysicalobjectsThecoordinatesof the trackedposition wereexpressedin theIGSreference frameAugmentedRealityVisualizationTheMicrosoftHoloLenswasusedforthevisualizationofvirtual3Dobjects(holograms)TheHoloLensusesaHMDwithvideosee-throughdisplaysThevirtualcontentisrendered3-dimensionallyinastereoscopicway2230ThecontentonaHMDisalwaysconsistentwiththeuser’s
