简介:本文介绍了双频识别声呐水下影像监测系统的工作原理,对通过仿射变换特征图像配准法对数据进行处理得到清晰整体图像的核心技术进行了分析论证;并通过系统在三河闸水下结构损坏监测中的运用情况,阐述了系统在我国水利工程水下监测中的推广应用前景。
简介:Amongexistingremotesensingapplications,land-basedX-bandradarisaneffectivetechniquetomonitorthewavefields,andspatialwaveinformationcouldbeobtainedfromtheradarimages.Two-dimensionalFourierTransform(2-DFT)isthecommonalgorithmtoderivethespectraofradarimages.However,thewavefieldinthenearshoreareaishighlynon-homogeneousduetowaverefraction,shoaling,andothercoastalmechanisms.Whenappliedinnearshoreradarimages,2-DFTwouldleadtoambiguityofwavecharacteristicsinwavenumberdomain.Inthisarticle,weintroducetwo-dimensionalWaveletTransform(2-DWT)tocapturethenon-homogeneityofwavefieldsfromnearshoreradarimages.Theresultsshowthatwavenumberspectraby2-DWTatsixparallelspacelocationsinthegivenimageclearlypresenttheshoalingofnearshorewaves.Wavenumberofthepeakwaveenergyisincreasingalongtheinshoredirection,anddominantdirectionofthespectrachangesfromSouthSouthWest(SSW)toWestSouthWest(WSW).Toverifytheresultsof2-DWT,waveshoalinginradarimagesiscalculatedbasedondispersionrelation.Thetheoreticalcalculationresultsagreewiththeresultsof2-DWTonthewhole.Theencouragingperformanceof2-DWTindicatesitsstrongcapabilityofrevealingthenon-homogeneityofwavefieldsinnearshoreX-bandradarimages.
简介:为验证宽波段高空间分辨率遥感卫星数据在小范围尺度水质监测上的可行性,基于GF-2号卫星数据,对中亭河的河水化学需氧量(COD)进行遥感监测,根据实地采样数据与遥感卫星数据的相关性建立经验模型,通过反演模型实现对河水COD的实时监测。实验结果表明:统计模型R2为0.8274,模型平均误差为4.9%,宽波段高空间分辨率遥感卫星数据在小尺度水质监测上是可行的。