简介:Withtherapiddevelopmentofglobalinformationhighway,multimediacommunicationtechnologyplaysamoreandmoreimportantroleinnationaleconomicandsocialdevelopment.However,themultimediacommunicationsystemisacomplicatedrealtimedistributedsystemanditssoftwareisdifficulttodevelop.Inordertoimprovetherapiddevelopmentandapplicationofthemultimediacommunicationtechnology,thereisanurgentneedtocarryoutthebasicresearchworkofsoftwaredevelopmentplatforminthisfield.
简介:Title:DiscontinuousDeformationAnalysisandRecentCrustalMovementAuthor:WANGZeminSupervisor:LIUJingnanThestudyfocusesonthewait_to_be_resolvedimportantdifficultproblem—howtoanalyzeandprocessthenumerousdataofcrustalmovementgainedbyrecentmeasuringmethodsoastodiscovertheinnermechanisms,thispaper,adopt
简介:Airborne3DimagewhichintegratesGPS,attitudemeasurementunit(AMU),scanninglaserrangefinder(SLR)andspectralscannerhasbeendevelopedsuccessfully.ThespectralscannerandSLRusethesameopticalsystemwhichensureslaserpointtomatchpixelseamlessly.Thedistinctiveadvantageof3Dimageisthatitcanproducegeo_referencedimagesandDSM(digitalsurfacemodels)imageswithoutanygroundcontrolpoints(GCPs).ItisnolongernecessarytosurveyGCPsandwithsomesoftwaresthedatacanbeprocessedandproducedigitalsurfacemodels(DSM)andgeo_referencedimagesinquasi_real_time,therefore,theefficiencyof3Dimageis10~100timeshigherthanthatoftraditionalapproaches.Theprocessingprocedureinvolvesdecomposingandcheckingtherawdata,processingGPSdata,calculatingthepositionsoflasersamplepoints,producinggeo_referencedimage,producingDSMandmosaicingstrips. Theprincipleof3Dimageisfirstintroducedinthispaper,andthenwefocusonthefastprocessingtechniqueandalgorithm.Theflighttestsandprocessedresultsshowthattheprocessingtechniqueisfeasibleandcanmeettherequirementofquasi_real_timeapplications.
简介:Severaldifferentstrategiesof3Dmodelingareadoptedfordifferentkindsofmanmadeobjects.Firstly,forthosemanmadeobjectswithregularstructure,if2Dinformationisavailableandelevationinformationcanbeobtainedconveniently,then3Dmodelingofthemcanbeexecuteddirectly.Secondly,forthosemanmadeobjectswithcomplicatedstructurecomparativelyandrelatedstereoimagespaircanbeacquired,inthelightoftopology-based3Dmodelwefinish3Dmodelingofthembyintegratingautomaticandsemi-automaticobjectextraction.Thirdly,forthemostcomplicatedobjectswhosegeometricalinformationcannotbegotfromstereoimagespaircompletely,weturntotopological3DmodelbasedonCAD.
简介:提出了一种以自动缩编为主、人工协调综合为辅的道路数据更新模式,引入并发展了线要素的自动匹配方法,实现了增量数据的自动提取和筛选、缩编,并从技术路线上详细阐述了增量更新的实现流程。
简介:SegmentationandedgeregulationarestudieddeeplytoextractbuildingsfromDSMdataproducedinthispaper.Buildingsegmentationisthefirststeptoextractbuildings,andanewsegmentationmethod-adaptiveiterativesegmentationconsideringratiomeansquare-isproposedtoextractthecontourofbuildingseffectively.Asub-image(suchas50×50pixels)oftheimageisprocessedinsequence,theaveragegraylevelanditsratiomeansquarearecalculatedfirst,thenthresholdofthesub-imageisselectedbyusingiterativethresholdsegmentation.Thecurrentpixelissegmentedaccordingtothethreshold,theaver-agegraylevelandtheratiomeansquareofthesub-image.Theedgepointsofthebuildingaregroupedaccordingtotheazimuthofneighborpoints,andthentheoptimalazimuthofthepointsthatbelongtothesamegroupcanbecalculatedbyusinglineinterpolation.
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简介:Thispaperdemonstratesanexperimentonthegenerationof3Dvirtualgeographicenvironmentonthebasisofexperimentalflightlaserscanningdatabyasetofalgorithmsandmethodsthatweredevelopedtoautomaticallyinterpretrangeimagesforextractinggeo-spatialfeaturesandthentoreconstructgeo-objects.Thealgorithmsandmethodsfortheinterpretationandmodelingoflaserscannerdataincludetriangulated-irregular-network(TIN)-basedrangeimageinterpolation;mathematical-morphology(MM)-basedrangeimagefiltering,featureextractionandrangeimagesegmentation,featuregeneralizationandoptimization,3Dobjectsreconstructionandmodeling;computergraphics(CG)-basedvisualizationandanimationofgeographicvirtualrealityenvironment.
简介:Dataacquisitionandmodelingarethetwoimportant,difficultandcostfulaspectsinaCybercityproject.2D-GISismatureandcanmanagealotofspatialdata.Thus3D-GISshouldmakethebestofdataandtechnologyof2D-GIS.ConstructionofausefulsyntheticenvironmentrequiresintegrationofmultipletypesofinformationlikeDEM,textureimagesand3Drepresentationofobjectssuchasbuildings.Inthispaper,themethodfor3Dcitylandscapedatamodelandvisualizationbasedonintegrateddatabasesispresented.Sincethedatavolumeofrasterareveryhuge,specialstrategies(forexample,pyramidgriddedmethod)mustbeadoptedinordertomanagerasterdataefficiently.Threedifferentmethodsofdataacquisition,theproperdatastructureandasimplemodelingmethodarepresentedaswell.Atlast,apilotprojectofShanghaiCybercityisillustrated.
简介:Basedonthearchitecturalsurveyprojectof“theChiLinNunneryRedevelopment'inHongKong,thispaperattemptstoinvestigatethetechniquesofbuilding3Ddigitaldocumentoflarge_scaletimberstructureandqualitycontrolduringconstructionbycomputer_based3Dsimulationforthewholeproject.Therewereseveralkeyissuesincludingprimarydataacquisition,3Dmodelinganddisplay,pre_assemblingthetotalbuildingandqualityexamination,etc.Inthispaper,someusefulexperiments,suchasthenewapplicationsofCCDdigitalcameras,imageandgraphprocessingsoftwarepackages(CAD,Photoshop,Photomodeler,Vexcel,etc.)tothearchitecturesarealsopresented.Thesemethodsintroducedinthispaperaresuitableforimageandgraphintegrateddatabasebuildingofcomplicatedarchitectures,andusefulforconvenientlymaintainingandreconstructingtheancientarchitectures.