简介:针对高分影像阴影检测精度易受水体、偏蓝色地物影响的问题,结合GF-1影像自身特点,提出一种集主成分变换、图像特征计算、逻辑非运算和形态学闭运算于一体的阴影检测方法。对GF-1影像多光谱数据、全色数据进行正射校正和信息融合,可实现光谱与分辨率信息的最大化利用,并最大程度地突出阴影信息,增大阴影与其他地物的差异。其次,建立基于主成分变换的阴影检测方法PC1/NIR和图像特征计算Rg_nir,得到初始阴影信息和水体信息;用初始阴影信息与水体信息作逻辑非运算,剔除水体,并利用形态学闭运算使得阴影区域更加连续、饱满。实验表明,该方法既能准确地检测出GF-1影像中的阴影信息,又能有效削弱水体、偏蓝色等地物的影响。
简介:Satelliteremotesensingofinlandwaterbodyrequiresahighspatialresolutionandamultibandnarrowspectralresolution,whichmakesthefusionbetweenpanchromatic(PAN)andmulti-spectral(MS)imagesparticularlyimportant.TakingtheDaquekousectionoftheQiantangRiverasanobservationtarget,fourconventionalfusionmethodswidelyacceptedinsatelliteimageprocessing,includingpansharpening(PS),principalcomponentanalysis(PCA),Gram-Schmidt(GS),andwaveletfusion(WF),areutilizedtofuseMSandPANimagesofGF-1.TheresultsofsubjectiveandobjectiveevaluationmethodsapplicationindicatethatGSperformsthebest,followedbythePCA,theWFandthePSintheorderofdescending.Theexistenceofalargeareaofthewaterbodyisadominantfactorimpactingthefusionperformance.Meanwhile,theabilityofretainingspatialandspectralinformationsisanimportantfactoraffectingthefusionperformanceofdifferentfusionmethods.ThefundamentaldifferenceofreflectivityinformationacquisitionbetweenwaterandlandisthereasonforthefailureofconventionalfusionmethodsforlandobservationsuchasthePStobeusedinthepresenceofthelargewaterbody.Itissuggestedthattheadoptionoftheconventionalfusionmethodsintheobservingwaterbodyasthemaintargetshouldbetakenwithcaution.Theperformancesofthefusionmethodsneedre-assessmentwhenthelarge-scalewaterbodyispresentintheremotesensingimageorwhentheresearchaimsforthewaterbodyobservation.
简介:为全面掌握潘家口水库水污染的真实状况,支撑库区近年来开展的水环境综合治理工作。本研究基于2016年10月11日高分一号卫星数据和实测数据,和潘家口水库30个实测水质样本,建立了叶绿素a和溶解氧的遥感估算模型,精度评价结果表明,叶绿素a和溶解氧估算模型总体平均相对误差为19.1%,可满足库区水质监测评估需要;试验期内根据遥感模拟结果发现,水库上游水质情况相对较好,中下游水质情况相对较差,库区水质情况与库区投饵网箱数量、周边生活污水排放量和工矿区污染源密切相关。本研究为库区水环境治理工作积累了一期关键的空间全覆盖的水质遥感监测成果,同时也可为未来库区水质业务化监测提供新的技术手段。
简介:Inthispaper,onlynarrow-senseprimitiveBCHcodesoverGF(q)areconsidered.Aformula,thatcanbeusedinmanycases,isfirstpresentedforcomputingthedimensionofBCHcodes.ItimprovestheresultgivenbyMacWilliamsandSloanein1977.AnewmethodforfindingthedimensionofalltypesofBCHcodesisproposed.Insecondpart,itisprovedthattheBCHboundistheleaderofsomecyclotomiccoset,andweguessthattheminimumdistanceforanyBCHcodeisalsotheleaderofsomecyclotomiccoset.
简介:Thispaperpresentsthelowerboundsandupperboundsforthemeanvalueandvarianceofdistancedistributionofnon-linearcodesinGF(q).Bypresentingseveralexamples,itisshownthattheseboundscouldbeachieved.