05高光谱遥感第五讲

Lecture5Atmospheric&GeometricCorrectionofHRSData™™™AtmosphereSpectralsignalatsensorwindow0()()()()cos()sunpLLTRLλλλλθλ=+™™™™()odsLLLLtλλλλλ=++λoLλsLλdLλtPlanetaryReflectanceFirst-orderapproximation–noknowledgeofatmosphere2cosdELsunpTOAπθρ=distanceEarth-SunirradianceericexoatmosphSolaranglezenithSolarradiancesensor)-(atatmosphereofTopereflectancPlanetary:Where=====dELsunTOApθρAtmosphericCorrectionAlgorithmImplementations™Useknowledgeofatmospheretodeterminetheconstantsnecessarytoconvertsatellitesignalstoscenereflectances9Ground-basedreflectancemeasurements(directmethod)9Pseudo-invarianttargets9Ground-basedatmosphere(aerosol)measurements9Scene-basedaerosolestimates(basedondarkpixels)9Climatologicalatmosphere9Satellite-basedatmosphericmeasurementsAtmosphericCorrection™Molecular&aerosolscattering&absorptionbygases(watervapor,ozone,oxygen,&aerosols)9Easytocorrectformolecularscattering&absorptionbyO3,O2&aerosolsbecauseofstableconcentrationsoftheseelementsovertime&space.9Mostdifficulttasktoestimatespatialdistributionsofaerosols&watervapordirectlyfromimagery™™™™“”™N“”MJNJ™()kkkkjiiiLabL=+Look-uptablemethod:radiativetransfercodesareusedoffline(tablesarecreatedbeforerunningatmosphericcorrectioncode)tocomputetablesforonlinecorrectionsE0μγ(μν)γ(-μ0)™E0γ(μν)γ(-μ0)vv0v(,,)(,,)1PErLLrs−=−+γ(−)γ()−0000μμΦμμΦμμμ™J™“”TOA()“”Jvvvv0v(,,)(,,)[(,,)(,,)]PPELLrLLs−−−=−−−+γ(−)γ()000000μμΦμμΦμμΦμμΦμμμ™E0γ(μν)γ(-μ0)™PL0Evγ()μγ(−)0μ™™™™0.5red2.1ρ=ρ0.25blue2.1ρ=ρ™™™biia−Γ=λ*ssvvtaStd’vµv=cosv'()(,,)(,,)(())1vssvsvasvsvttvdtTSetτμθρθθφφρθθφφρρθρ−∗−=−++−196S9MODTRAN/LOTRAN9SMACetc.Atmosphericcorrection:complex™Radiativetransfermodelssuchas6Srequire:™Geometricalconditions(view/illum.angles)™Atmosphericmodelforgaseouscomponents(Rayleighscattering)™H2O,O3,aerosolopticaldepth,τ(opacity)™Aerosolmodel(typeandconcentration)(Miescattering)™Dust,soot,saltetc.™Spectralcondition™bandsandbandwidths™Groundreflectance(typeandspectralvariation)™surfaceBRDF(defaultistoassumeLambertian….)™Ifnoinfo.usedefaultvalues(StandardAtmosphere)MODTRAN0()()()1tvvdvtLLFTSρμμμρ=+−2(2)t00()()()(()())vvtdvvvLLFTSLLμμρμμμ−=+−3MODTRANMODTRAN4tape5tape5CARDS()tape5CO2BRDF9999999999ééSimulationofthesatellitesignalinthesolarspectrum9999999AfterBefore–Darkpixelsappearbrighterandbrightpixelsappeardarker™ATREMColoradoAVIRIS0.4~2.5μm9AVIRIS995SρaS,T(θa)T(θv)9Sρ*;90.94μm-1.14μm,Tg;95S.™ACORNColoradoImSpec0.35μm-2.5μm9MODTRAN40.941.1499MODTRAN9ACORN7™FLAASHACORNMODTRAN40.4-2.5μmACORN™6S™ATCORAtmosphericCorrection(ATCOR)isanadd-onmoduletotheERDASIMAGINE®productsuitethateliminatesatmosphericandilluminationeffects.™TheATCORmodulewasoriginallydevelopedatDLR,theGermanAerospaceCentreandintegratedbyLeicaGeosystems’GermandistributorGEOSYSTEMSGmbHforERDASIMAGINE.™ATCORconsistsofATCOR2andATCOR3.ATCOR2isusedforatmosphericcorrectioninflatterrain.ATCOR3isusedforatmosphericcorrectioninruggedterrainbyintegratingaDEM.™Landsat-4/5TM,MSS,Landsat-7ETM+,SPOT,IRS-1A/-1BLISS-2,IRS-1C/-1DLISS-3,IRS-1C/-1DWiFS,IKONOS,MOS-B,MOMS-02,ResursMSU-E,ASTER,QuickBirdzz™()™1.……2.3.4.5.6.™™™™™™™™™™h*ikkkki’‡99™X™POS/DGX™PS,PePS,Pe(xs,ys),(xe,ye)™™,BezierBezierBezierP1,P2,P3,P4™™PsPePs,Pe,Ps,Pe,Pi,(xi,yi),Ps,Peykxb,™yeysxexsyiyi™™™POS/DG™POS/DGGPS™IMUGPSPCSPOSPacTM™IMU/DGPSGPSPOS/DGGPSGPS™IMU/DGPSPOS/DGBeforegeometriccorrectionAftergeometriccorrectionbasedonPOS/DGDevelopmentofHyperspectralImage-processingSoftwareHRS/IRSA/CASHRS/IRSA/CASJUN.2004JUN.2004MausoleumofEmperorQinshihuang™357