简介:ThemethodtopumptheFBGwrittenintoanEr3+-dopedopticalfiberisproposedtoincreasethegroupvelocityofaprobingpulsebasedonthefactsthatpump-inducedprocesschangestherefractiveindexanddispersionassociatedwiththe4I15/2-4I13/2transitioninEr3+-dopedopticalfiber.Thesystemequationsarederived.Theeffectsofpumppoweranddopingconcentrationonthegroupvelocityarediscussed.
简介:Inthispaperweproposeathreedimensionalmultiplierlessdiscretecosinetransform(DCT)withliftingschemecalled3D-binDCT.Basedon3D-binDCT,anovelvideocodingalgorithmwithoutmotionestimation/compensationisproposed.Itusesthe3D-binDCTtoexploitspatialortemporalredundancy.ThecomputationofbinDCTonlyneedsshiftandadditionoperations,thusthecomputationalcomplexityisminimized.DCcoefficientprediction,modifiedscanmodeandarithmeticcodingtechniquesarealsoadopted.Extensivesimulationresultsshowthattheproposedcodingschemeprovideshighercodingefficiencyandimprovesvisualquality,anditiseasytoberealizedbysoftwareandhardware.
简介:Theclosephotogrammetric3-Dcoordinatemeasurementisanewmeasuringtechnologyinthefieldsofthecoordinatemeasurementmachine(CMM)inrecentyears.Inthismethod,weusuallyplacesometargetsonthemeasuredobjectandtakeimageoftargetstodeterminetheobjectcoordinate.Thesubpixellocationoftargetimageplaysanimportantroleinhighaccuracy3-Dcoordinatemeasuringprocedure.Inthispaper,somesubpixellocationmethodsarereviewedandsomefactorswhichaffectlocationprecisionareanalyzed.Thenweproposebilinearinterpolationcentroidalgorithm.Theexperimentshaveshownthisalgorithmcanimproveaccuracyoftargetcentroidbyincreasingavailablepixels.
简介:Byusingthecenterprojectionimagesequencetoestimate3-Dmotionparameters,oneneedstoknowthecorrespondingrelationshipbetweenthefeatureofmotionobjectinspaceandtheprojectioncoordinateonimageplane.Inordertoavoidusingtherelationshipoffeaturecorrespondence,thetensoranalysismethodintheaffinetransformationsystemispresented,andthesimulationdataofexperimentalresultsaregiven.
简介:Thispaperpresentsahandheld3Dvision-basedscannerforsmallobjectsbyusingKinect.Itisdifferentfromthepreviouscolor-glove-basedapproacheswhichrequiresegmentingthetargetobject.First,weeliminatethenoisesandtheoutlierscausedbyholdinghands.Second,weapplyKinect-fusionalgorithmandtruncatedsigneddistancefunction(TSDF)torepresent3Dsurfaces.Third,weproposeamodifiedintegrationstrategytoeliminatethehandeffect.Fourth,wetakeadvantageoftheparallelcomputationofGPUsforreal-timeoperation.Themajorcontributionsofthispaperare(1)theregistrationprecisionisimproved,(2)theofflineamendmentandloopclosureoperationarenotrequired,and(3)concave3Dobjectreconstructionisfeasible.IndexTermsHandheld3Dscanning,Kinect-fusion,Truncatedsigneddistancefunction(TSDF).1.IntroductionRecently,thesensor-based3Dmodelreconstructionmethodshavebeenproposed[1].Thesensordeviceshavedifferentpropertiessothatthe3Dreconstructionalgorithmsvaryaccordingly.Thecommonlyusedsensordevicesaretime-of-flight(ToF)cameras[2]-[4],laserscanners[5],andstructuredlightscanners[6],[7].Lasershavegainedareputationforaccuracy;however,caremustbetakentouseeye-safelaserswhenoperatinginproximitytohumans.Foraninteractivesystem,thestructuredlightscannerwhichisbasicallyapassivevision-basedsensordeviceissuperiorbecauseitprovidesa2DdepthimageperframeandismoreaccuratethanthatofaToFcamera.Here,wepresentareal-time3DscannerusingthedepthimagescapturedbyKinect.
简介:Micro-structures3-Dprofilemeasurementisanimportantmeasurementcontentforresearchonmicro-machiningandcharacterizationofmicro-dimension.Inthispaper,anewmethodinvolved2-Dstructuretemplate,whichguidesphaseunwrapping,isproposedbasedonphase-shiftingmicroscopicinterferometry.Itisfitnotonlyforstaticmeasurement,butalsofordynamicmeasurement,especiallyformotionofMEMSdevices.3-Dprofileofactivecombofmicro-resonatorisobtainedbyusingthemethod.Thetheoreticprecisioninout-of-planedirectionisbetterthan0.5nm.Thein-planetheoreticprecisioninmicro-structuresisbetterthan0.5μm.Butattheedgeofmicro-structures,itisonthelevelofmicrometermainlycausedbyimpreciseedgeanalysis.Finally,itsdisadvantagesandthefollowingdevelopmentarediscussed.
简介:Organicmultiplequantumwells(OMQWs)consistingofalternatinglayersoforganicmaterialshavebeenfabricatedfromtris(8-hdroxyquinoline)aluminum(Alq)and2-(4-biphenylyl)-5-(4-tertbutylphenyl)-1,3,3-oxadiazole(PBD)byamultisource-typehigh-vacuumorganicmoleculardeposition.Fromthesmall-angleX-raydiffractionpatternsofAlq/PBDOMQWs,aperiodicallylayeredstructureisconfirmedthroughtheentirestack.TheAlqlayerthicknessintheOMQWswasvariedfrom1nmto4nm.Fromtheopticalaborption,photoluminescenceandelectroluminescencemeasurements,itisfoundthattheexcitonenergyshiftstohigherenergywithdecreasingAlqlayerthickness,ThechangesoftheexcitonenergycouldbeinterpretedastheconfinementeffectsofexcitonintheAlqthinlayers.Narrowingoftheemissionspectrumhasalsobeenobservedfortheelectroluminescentdevices(ELDs)withtheOMQWsstructureatroomtemperature.