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:SegmentationandedgeregulationarestudieddeeplytoextractbuildingsfromDSMdataproducedinthispaper.Buildingsegmentationisthefirststeptoextractbuildings,andanewsegmentationmethod-adaptiveiterativesegmentationconsideringratiomeansquare-isproposedtoextractthecontourofbuildingseffectively.Asub-image(suchas50×50pixels)oftheimageisprocessedinsequence,theaveragegraylevelanditsratiomeansquarearecalculatedfirst,thenthresholdofthesub-imageisselectedbyusingiterativethresholdsegmentation.Thecurrentpixelissegmentedaccordingtothethreshold,theaver-agegraylevelandtheratiomeansquareofthesub-image.Theedgepointsofthebuildingaregroupedaccordingtotheazimuthofneighborpoints,andthentheoptimalazimuthofthepointsthatbelongtothesamegroupcanbecalculatedbyusinglineinterpolation.
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.
简介:构造一个煤矿的虚拟景色是的3D为在煤采矿上现代化并且处理信息的客观要求生产。建立“一个数字矿”也是关键技术。由探索当前的世界范围的研究,软件和硬件工具和应用程序要求,与案例研究地点(Pingdingshan煤组的Daz-huang矿)结合了,为一个矿的3Dgeo可视化的一条途径出现工厂和矿车道深深地被讨论。在这研究,虚拟景色基于弧/信息和Site-Builder3D被学习的为一个大范围的快速的建模方法,和从2D景色的3D景色的自动产生被认识到。能从2D把矿车道系统变换成3D的如此的一个自动方法为Dazhuang矿被认识到。一些相关应用程序问题被学习,包括在在矿表面的虚拟景色的虚拟场面种的2D和3D和矿车道之间的属性质问,并列质问,距离措施,碰撞察觉和动态相互作用。一个原型系统被设计并且发展。
简介:通过解译徐州市矿区1990年、2000年、2010年3期TM影像,获取土地利用类型、面积、斑块数等属性数据。利用Fragstats软件,计算3个时期各地类的分形维数和稳定性指数。在分析3个时期土地利用数量变化的基础上,研究分形维数与稳定性指数的动态变化特征,从不同地类的空间形态的变化上定量探讨徐州矿区20a土地利用的演变。结果表明,1990~2000年,徐州矿区空间形态趋于简单,稳定性上升;2000年是一个转折点,1990年相对于2000年,5类地物分维数降低,稳定性上升;2010年相较于2000年,特别是建成区与耕地这2类地物分形维数上升,稳定性下降幅度较大。在城市化驱动下,经济发展,城市扩张,生态保护是区域土地利用分形特征与结构稳定变化的主要驱动因素。