S技术在水利工程中的应用-遥感

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1、RemoteSensing遥感RemoteSensingLastLectureAbsorptionfeaturesVegetationSoilsRocksandmineralsWater,iceandsnowConclusionsLastLectureEMRwhichhasinteractedwithmatterwillbedeficientinsomewavelengths,duetoabsorptionprocessesoccurringatatomicormolecularscalesTheseabsorptionfeaturescreatedistinctive“spectra

2、lsignatures”fordifferentEarthsurfacetypesThesecanbeexploitedby“multispectral”remotesensingmethodsformappingandmonitoringpurposesRemoteSensingSpectralSignaturesRemoteSensingRemoteSensing地表任一点反射的电磁波被分解为若干个波段，每个波段有一个反射率RemoteSensing反射率的大小用灰度表示，并被转换成数字信号，通常是28（0-255）504030201000.40.60.70.81.3REFLECT

3、ANCE(%)Wavelength(micrometers)Visible0.5NearIRGrassGREENBLUEGREENREDBLUEGREENREDNEARIRNearIRBandPlacementBandDisplayBand1Band2Band3Band4Band5Band7BLUEGREENREDNEARIRSHORTWAVEIRMID-WAVEIRNEARIRColorTheoryAllcolorscreatedfromadditiveprimarycolors:RedGreenBlueComplementarycolors:MagentaYellowCyanRed

4、GreenBlueMCYWBlackMultispectralDisplayBLUEGREENREDNEARIRSHORTWAVEIRMID-WAVEIRLONGWAVEIR1LandsatTMBand234576BandCombination=742(LANDSAT)ColorGuns=BandCompositeOutput=Band3VisibleRedBand2VisibleGreenBand1VisibleBlueIndividualLandsatBandsAppliedtoColorGunsResultingImageBand4NearInfraredBand3Visible

5、RedBand2VisibleGreenIndividualLandsatBandsAppliedtoColorGunsResultingImageAVRISHyperspectralCubeAirborneVisible/InfraredImagingSpectrometer224spectralchannels400–2500nmspectralresolution,20metergroundresolution.BrineShrimppondSensingSensorarrayLens225214199198202176Each“cell”recordedasa“digitaln

6、umber”(DN)or“brightnessvalue”MeasuresamountofEMradiationThebrighterthesignal,thehigherthevalue.PixelsEachcelliscalleda“pictureelement”,orpixelEachpixelrepresentsasinglebrightnessvalueforaspecificgeographicalarea225204188146214198169152202200178162icolumnsjrowsixj=4x4=16pixels11410910197SensorPro

7、pertiesSpatialresolutionSpectralresolution/#bandsRadiometricresolutionTemporalresolutionSource:NASASpatialResolutionMeasureofthesmallestangularorlinearseparationbetween2objectsthatcanberesolvedbythesensorInpractice,sensorsys