Introduction
Whatisvisualization?
Thelargeamountofdatageneratedbyawidevarietyofinformationsourcesfarexceedstheabilityofthehumanbraintoanalyzeandinterpretthesedata.Duetothelackofeffectiveanalysismethodsforlargeamountsofdata,about95%ofthecalculationsarewasted,whichseriouslyhinderstheprogressofscientificresearch.Tothisend,theUnitedStatesComputerImagingProfessionalCommitteeproposedasolution-visualization.Asthemosteffectivemeansofinterpretingalargeamountofdata,visualizationtechnologywasfirstadoptedbythefieldsofscientificandengineeringcomputing,anddevelopedintoacurrentpopularresearchfield—scientificvisualization.Visualizationtransformsdataintographics,givingpeopledeepandunexpectedinsights,andfundamentallychangesthewayscientistsdoresearchinmanyfields.Theapplicationofvisualizationtechnologyrangesfromhigh-speedflightsimulationstomolecularstructuredemonstrations,everywhere.IntheInternetera,thecombinationofvisualizationandnetworktechnologyhasmaderemotevisualizationservicesareality,andthevisualareanetworkhasemergedasthetimesrequire.ItisanewconceptproposedbySGIinMarch2002.Itscoretechnologyistovisualizeserverhardwareandsoftware.Themainprocessofscientificvisualizationismodelingandrendering.Modelingistomapdataintogeometricprimitivesofobjects.Renderingisthedepictionofgeometricprimitivesasgraphicsorimages.Renderingisthemaintechniqueforrenderingrealisticgraphics.Strictlyspeaking,renderingistocalculatethebrightnessandcolorcompositionofthevisiblesurfaceoftheobjectprojectedtotheobserver’seyesaccordingtothelightingmodelbasedontheopticalprinciple,andconvertitintoacolorvaluesuitableforthegraphicsdisplaydevice,therebydeterminingeachimageontheprojectionscreen.Thecolorandlightingeffectsofonepixelfinallygeneraterealisticgraphics.Realisticgraphicsareexpressedbythecolorandlightanddarktonesofthesurfaceoftheobject.Itisrelatedtothematerialpropertiesofthesurfaceoftheobjectandthelightenergyradiatedfromthesurfacetothelineofsight.Thecalculationiscomplicatedandtheamountofcalculationislarge.Therefore,theindustryhasinvestedalotofefforttodeveloprenderingtechnology.
Visualizationhardware
Thevisualizationhardwareismainlygraphicsworkstationsandsupervisualizationcomputers.GraphicsworkstationswidelyuseRISCprocessorsandUNIXoperatingsystems.Ithasrichgraphicsprocessingfunctionsandflexiblewindowmanagementfunctions,canbeconfiguredwithlarge-capacitymemoryandharddisk,hasagoodhuman-computerinteractioninterface,input/outputandnetworkfunctions.Itismainlyusedinscienceandtechnology.In1997,SGIlaunchedaUMAstructureO2workstationwithoutabus.Itusesahigh-bandwidthmemorysystem,eliminatingvideocards,graphicscards,andimagecards.Graphicsprocessing,imageprocessing,videoprocessing,memoryandmainmemoryarereplacedbyaunifiedmemorysystem,andthebandwidthcanreach2.1GB/s.TheCPUandvideodisplaycandirectlyaccesstheunifiedmemorysystem.Inaddition,ithasaseparatewindowinterfacethatallowsuserstoaccesstheWebsitethroughthiswindow,andafilelistisatthetopofthewindow,whichisconvenientforuserstomanagemediaresources.In2000,SGIlaunchedOctane2,apowerfuldesktopworkstation.Octane2organicallycombinesabreakthroughnewgenerationofVpro3Dgraphicssystem,advancedcrossbarstructureandthelatestMIPSRISCprocessor.WithOctane2anditsunprecedentedaccuracy,interactivityandfastgraphicscapabilities,userscansolvethemostchallengingthree-dimensionalmodeling,visualizationandgraphicsprocessingproblems.Octane2containsthecorefunctionsofOpenGL1.2integratedonachipandsomehardwareaccelerationfunctionsforimageexpansion.Itcanusehardwaretorealizethecalculationofspecularlighting,canquicklyandaccuratelyshowthecurvedsurface,andhasthefunctionof48-bitRGBA.Itistoday'shigh-levelvisualizationdesktopworkstation.Itcanprovideuserswithdual-channeldual-headdisplay.InJuly2000,SGIlaunchedtheOnyx3000seriessupergraphicssystemthatperfectlycombinesvisualizationandsupercomputing.Onyx3000hastakenabigsteptowardsmodularity.Thesystemhardwareconsistsof7modules:graphicsexpansionmoduleG-brick,basicinput/outputexpansionmoduleI-brick,PCIexpansionmoduleP-brick,high-performanceI/OexpansionmoduleX-brick,routerinterconnectionexpansionmoduleR-brick,CPUexpansionmoduleC-brickanddiskexpansionmoduleD-brick.ThewholemachineadoptsNUMA3architecture.High-performancemodularconnectivityfacilitatestheseamlessintegrationofsupercomputingcapabilitiesandvisualizationprocessing.Thewholemachinecanbeexpandedfrom2CPUsto512CPUs.Onyx3000adoptsInfiniteReality3graphicsprocessingpipeline,whichcanrenderthree-dimensionalshapesinrealtime.Theseincludefunctionssuchascolor,transparency,texture,andlighting.InFebruary2002,SGIlaunchedtheOnyx3000IPmachine,usingtheInfinitePerformancegraphicsprocessingpipelinewithbetterperformance,fasterspeedandmorerefinedgraphics.Onyx3000'sexcellentperformanceandflexibilitycanenableuserstogetamazingvisualreality,andfullyprotectusers'investment.
Visualizationsoftware
Visualizationsoftwareisgenerallydividedintothreelevels.Thefirstlayeristheoperatingsystem.Apartoftheprogramdirectlyinteractswiththehardwaretocontroltheworkofvariousmodulesoftheworkstationorsupercomputer.Theotherpartoftheprogramcanperformtaskscheduling,videosynchronizationcontrol,andtransmitgraphicsinthenetworkbyTCP/IP.Informationandcommunicationinformation.Thesecondlayeristhevisualizationsoftwaredevelopmenttool,whichisusedtohelpdevelopersdesignvisualizationapplicationsoftware.Thethirdlayeristhevisualizationapplicationsoftwareusedbyallwalksoflife.Mostvisualizationworkisgenerallyperformedongraphicsworkstations,andafewlarge-scalevisualizationworkthatrequirescollaborativeworkisperformedonsupergraphicscomputers.SGIisoneofthepioneersofvisualcomputingtechnology.Withthesupportofpowerfulhigh-speedgraphicshardware,SGIhaslaunchedaseriesofpowerfulvisualizationsoftwaredevelopmenttools,suchasIRISGL(graphicslibrary),IL(imagelibrary),VL(videolibrary)),ML(MovieLibrary),CASEVision(SoftwareEngineeringVisualizationDevelopmentTool),etc.,amongwhichIRISGLwaslateracceptedbytheindustryandbecameanindustryopenstandardcalledOpenGL.OpenGLsupportsanimmediateinterface,andinformationcanflowdirectlytothedisplay.SGIhasalsodevelopedmanyOpenGLapplicationprogramminginterfaces(APIs).Forexample,OpenGLOptimizerisamulti-platformtoolboxthatprovideshigh-levelconstruction,interactiveoperations,andprovidesoptimalgraphicsinCAD/CAM/CAEandAECapplications.Function.OpenGLVolumizerisabreakthroughtoolforvolumerendering,facilitatingthevisualizationofvoxel-baseddatasets.OpenGLPerformerisareal-time3Dgraphicsrenderingtool.OpenGLInventorisathree-dimensionalvisualprocessingtool.OpenGLVizServerisatoolthatprovidesremotevisualizationservices.SinceOpenGLwaslaunched,morethantwothousandthree-dimensionalgraphicsapplicationshavebeendevelopedonit.SuchasA/Wcompany’sthree-dimensionalanimationsoftwareMaya,PTCcompany’sCAD/CAM/CAEapplicationsoftwarePro/Engnieer.Landmark'spetroleumexplorationanddevelopmentsoftwareR2003,MultiGen'svisualsimulationsoftwareParadigm,etc.
Datavisualizationistheuseofcomputergraphicsandimageprocessingtechnology,scientificandtechnologicalresearchontheformofdatarepresentation.
VisualizedAreaNetwork
Thecurrentdrivingforcefortheadvancementofgraphicstechnologyis:·Withthecontinuousgrowthofdata,itcanprovidecommercialgraphicsrenderingproducts;·Withthecontinuousgrowthofdata,Abroadbandnetworkthatcaneconomicallyprovidealargeamountofdata;·Inordertostrengthencollaboration,globalgroupsarerequiredtoprovideglobalizeddata.Thecoretechnologytosolvetheabovethreeproblemsis:theuseofscalablegraphicscomputers,suchasOnyx3000andtheuseofOpenGLVizServerremotevisualizationserversoftware.AfteradoptingOpenGLVizServer,generalclientdevicescanaccessadvancedvisualcomputingresourcesthroughthenetwork.Thevisualizationareanetwork(VAN)withOnyxsupervisualizationcomputerandremotevisualizationserversoftwareOpenGLVizServerasthecorecanbeusedbytheglobalcommunitytousegeneralclientstoaccessthesupervisualizationcomputingresourcesplacedsomewherethroughtheInternet.
WhyisVANfeasiblenow?
Fiveyearsago,duetotechnicalreasons,peoplefocusedonthedevelopmentofadvancedgraphicsrenderingtechnology.Thecurrentmainproblemishowtomakegraphicsrenderingproductscheaper.Themainprobleminthenextfiveyearsishowtomakethegraphicsrenderingresultsavailabletogroupsandindividualseverywhere.Tosolvetheaboveproblems,VizServer2.0softwarecanbeused,whichcanenablegroupsandindividualsanywhereintheworldtoobtaintheresultsofgraphicsrendering.Thisisthekeytoachievingscalable,collaborative,andgloballyavailablegraphics.VizServereliminatesthebarriersthatmustbephysicallyconnectedtoadvancedgraphicsrenderingsystems,makingcollaborativeresearchnotrestrictedbygeographiclocation,andachievingtransparentapplicationcollaboration.
HowdoesVizServerwork?
·Graphicrenderingiscompletelyrealizedonsupervisualcomputingresources(suchasOnyx3000);·Graphicrenderingresultsaretransmittedtotheclientthroughthenetworkframebyframe;·Theclientdecompressesthegraphicsrenderingresults.Theclientonlyneedstosendthecontrolflow,andtheback-endvisualresourcesendsthedataflowaccordingtothecustomer'srequirements(seethepicture).Firstofall,theremustbeadvancedvisualizationnodesinVAN,forexample,institutional-levelOnyx3000ordepartment-levelOnyx300orindividual-levelSiliconGraphicsFuelworkstationsorOnyx3000advancedvisualizationcomputerscanbeused,andsecondly,remotevisualizationserversoftwareOpenGLVizServer2.0canbeused.VizServer'sapplicationperformanceandbandwidthcanmeettherequirementsofeconomicallytransmittinggraphicsrenderingresultsonthecurrentexistingnetwork.
Applicationofremotevisualizationserver
SGIcompanydemonstratedremotevisualizationserviceinCanada.OnNovember8,2001,SGIannouncedthesuccessofitsremotevisualizationservicetrial.ThepurposeofthisdemonstrationistoshowthevariousfunctionsandoverallperformanceoftheSGIvisualizationserviceenvironmentdevelopedbySGIbasedonSGIOpenGLVizServertechnology.FromJunetoAugust2001,SGIconductedthisremotevisualizationservicetrialonCA*net3,CANARIE'shigh-bandwidthnetworkthroughoutCanada.TheOpenGLVizServersolutionusedenablesordinarydesktopusersrunningIRIX,Linux,SolarisorWindowsNToperatingsystemstoalsouseallthefunctionsoftheSGIOnyx3000seriesofhigh-performancevisualizationsystems.Thissolutionenablesalargenumberofnetworkuserstosharedata,computingpower,andvisualizationsystemresourcesonthegridthroughthegrid.Theso-calledgridcomputingisamethodofinterconnectingvariouscomputingresourcesdistributedindifferentgeographicallocations,suchassupercomputers,clusters,storagesystems,andvisualizationsystems,throughtheInternetoradedicatednetwork,toformaresourceasawhole.ThisexperimentusedaSGIOnyxseriesvisualizationsystemlocatedintheMcConnellBrainImageResearchCenterofMcConnellUniversity,andremotelyoperatedvariousgraphicdisplayandoperationfunctionsgeneratedbythissystemfromacity100to1,900milesawayfromthecenter.TheresultsoftheexperimentonceagainconfirmedthatthedesktopworkstationcaninteractivelyaccessthegraphicsgeneratedonaSGIOnyxseriessysteminMontreal.Thevisualizationserviceenablesanyusertointeractwiththesupercomputingresultsthroughthegrid.ScientistsacrossCanadacanusethevisualizationresourcesofcomputinganywhereinCanada,andcaninteractivelyvisualizetheseresourcesontheirdesktopcomputers.SGIcompanyheldthecompany'svisualizationsummitattheGlasgowScienceCenter,duringwhichSGIshowedtheaudiencethelatestdevelopmentoftheconceptofvisualizationareanetworkinavividway.Withavisualareanetwork,scientistsandengineerscanstoreandprocessdatainoneplace;then,everyonecanuseanyclientdeviceonthenetworktooperatethesedataindividuallyorcollaborativelythroughtheexistingnetwork.,Surgeons,scientists,engineers,andinnovativetechniciansallovertheworldcantakeadvantageofthepowerfulfunctionsofhigh-performancecomputers.
Keytechnology
Nameserviceandresourceretrievaltechnology
Foramonitoringandmanagementplatformthatmanageshundredsofthousandsofcameraresources,itcanquicklyretrieveresourcesIsaveryimportantissue.Theadvanced"nameservice"methodisadoptedinthedesign,whichcaneffectivelyrealizetheunifiednamingandfastretrievalofallresources.Theimplementationplanistodefineanindependentnameandattributeforeachcamera.Theattributesincludecamera-relatedcodingequipment(suchasDVR),controlequipment(suchasmatrix),storageandbackupequipment(suchasNVR),andmediaforwardingequipment(suchasmedia).Server)information(suchasIPaddress,portnumber,channelnumber).Thesystemcanusethreemethodstodisplayandretrievethecamera:searchbyname(supportfuzzysearch),searchbyresourcecatalog,andsearchbyGISgeographicinformationservice.Allsearcheswilleventuallylocatethenameoftheresource,andlocatetherelatedinformationoftheresourcethroughtheresourcename.Thesystemcanusethisinformationtorealizeglobalnetworkedvideobrowsing,recording,storageandbackup,PTZcontrol,videodistribution,andothermanagementapplicationfunctions.
Integrationtechnologyofheterogeneoushardware
Forprovincialvideosurveillancesystems,thefront-endcameras,encoders,controllersandalarmequipmentusedwillfaceavarietyofmanufacturersandModelintegrationproblem.Forexample,thereare8networkvideoserversuppliersshortlistedinGuangzhou,morethan10digitalharddiskvideorecordermanufacturers,andmorethan20cameramanufacturers.SincethereiscurrentlynounifiedcodingstandardandPTZcontrolprotocol,eachmanufacturer’sencodingequipmentoutputThedigitalvideoandaudiosignalsandcontrolprotocolsaredifferent,andthecontrolcommandsofeachcameraarealsodifferent.Howthemanagementplatformdisplaysandstoresthevideoandaudioinformationofthefront-enduniformly,anduniformlycontrolsthedifferentPTZdevicesofthefront-endisamajortechnicalproblem.Thisrequiresagoodsolutiontothisproblem,toachievecompleteintegrationbetweenequipmentofdifferentmanufacturers,includingthroughunifiedcommunicationprotocolconversionandmediadecodingsoftwaretoachievevideoimagesofdifferentencodingformatsontheclientworkstation;throughaunifiedvideowallThemanagementsoftwarecanswitchanddisplaythevideosignalstransmittedbytheequipmentofdifferentmanufacturersontheTVwall;realizethecontrolofthefront-endPTZequipmentofdifferentmanufacturersthroughaunifiedcontrolcommand.