简介:Multi-beamSonarandSide-scanSonarcompensateeachother.Inordertofullyutilizeallinformation,itisnecessarytofusetwokindsofimageanddata.Andtheimageco-registrationisanimportantandcomplicatedjobbeforefusion.Thispapersuggestscombiningbathymetricdatawithintensityimage,obtainingthecharacteristicpointsthroughtheminimalanglesoflines,andthendecidingthecorrespondingimagepointsbythemaximalcorrelatecoefficientinsearchingspace.Finally,thesecondorderpolynomialisappliedtothedeformationmodel.Aftertheimageshavebeenco-registered,Waveletisusedtofusetheimages.Itisshownthatthisalgorithmcanbeusedintheflatseafloorortheisotropicseabed.Verificationismadeinthepaperwiththeobserveddata.
简介:Themultibeamsonarscanprovidehydrographicqualitydepthdataaswellasholdthepotentialtoprovidecalibratedmeasurementsoftheseaflooracousticbackscatteringstrength.Therehasbeenmuchinterestinutilizingbackscattersandimagesfrommultibeamsonarforseabedtypeidentificationandmostresultsareobtained.Thispaperhaspresentedafocusedreviewofseveralmainmethodsandrecentdevelopmentsofseafloorclassificationutilizingmultibeamsonardataor/andimages.Theseareincludingthepowerspectralanalysismethods,thetextureanalysis,traditionalBayesianclassificationtheoryandthemostactiveneuralnetworkapproaches.
简介:Sonarimageshavecomplexbackground,lowcontrast,anddeteriorativeedges;thesecharacteristicsmakeitdifficultforresearcherstodisposethesonarobjects.Themulti-resolutionanalysisrepresentsthesignalsindifferentscalesefficiently,whichiswidelyusedinimageprocessing.Waveletsaresuccessfulindisposingpointdiscontinuitiesinonedimension,butnotintwodimensions.ThefiniteRidgelettransform(FRIT)dealsefficientlywiththesingularityinhighdimension.Itpresentsthreeimproveddenoisingapproaches,whicharebasedonFRITandusedinthesonarimagedisposaltechnique.Byexperimentandcomparisonwithtraditionalmethods,theseapproachesnotonlysuppresstheartifacts,butalsoobtaingoodeffectinedgekeepingandSNRofthesonarimagedenoising.
简介:Anewgray-spatialhistogramisproposed,whichincorporatesspatialinformationwithgraycompositionswithoutsacrificingtherobustnessoftraditionalgrayhistograms.Thepurposeistoconsidertherepresentationroleofgraycompositionsandspatialinformationsimultaneously.Eachentryinthegray-spatialhistogramisthegrayfrequencyandcorrespondingpositioninformationofimages.Intheexperimentsofsonarimagerecognition,theresultsshowthatthegray-spatialhistogramiseffectiveinpracticaluse.
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简介:Amultiple-inputmultiple-output(MIMO)sonarcansynthesizealarge-aperturevirtualuniformlineararray(ULA)fromasmallnumberofphysicalelements.However,thelargeapertureisobtainedatthecostofagreatnumberofmatchedfilterswithmuchheavycomputationload.Toreducethecomputationload,aMIMOsonarimagingmethodusingavirtualsparselineararray(SLA)isproposed,whichcontainstheofflineandonlineprocessing.Intheofflineprocessing,thevirtualULAoftheMIMOsonaristhinnedtoavirtualSLAbythesimulatedannealingalgorithm,andmatchedfilterscorrespondingtoinactivevirtualelementsareremoved.Intheonlineprocessing,outputsofmatchedfilterscorrespondingtoactiveelementsarecollectedforfurthermultibeamprocessingandhence,thenumberofmatchedfiltersintheechoprocessingprocedureiseffectivelyreduced.Numericalsimulationsshowthattheproposedmethodcanreducethecomputationloadeffectivelywhileobtainingasimilarimagingperformanceasthetraditionalmethod.
简介:Toreducethecomputationburdenofalarge-aperturemultiple-inputmultiple-output(MIMO)sonarimagingsystem,thephase-shiftbeamformer(PSBF)isusedatthecostofbringingtheintensityloss(IL).ThecauseoftheILisanalyzedindetailandavariabletermedasILfactorisdefinedtoquantifythelossamount.TocompensatefortheIL,twomethodstermedasintensitycompensationforthePSBF(IC-PSBF)andthehybridbeamforming(HBF),respectively,areproposed.TheIC-PSBFusespreviouslyestimatedILfactorstocompensateforoutputintensitiesofallPSBFs;andtheHBFappliestheIC-PSBFtothecenterbeamregionandtheshifted-sidebandbeamformer(SSBF)tothesidebeamregion,respectively.Numericalsimulationsdemonstratetheeffectivenessofthetwoproposedmethods.
简介:Withtheincreasingofdetectionabilityofpassivesonar,theweaksignaldetectionprobleminmultipleinterferencesbecomesmoreandmoreimportant.Inthetime/bearingrecord(TBR)displayofsonardetection,whenthereexisttracesofmultipleinterferences,theidentificationofweaksignalisdifficultorimpossible.Theadaptivenoisecancellationtechniqueprovidesthetheoreticalbasisforsuppressingstronginterferences.Butthesolutionforfindingthesteady-stateoptimumfiltermatrixisquitedifficultduetotherealtimecalculationofinversematrixofinputdatacorrelationmatrix.Theiterativeinversebeamforming(IBF)algorithmforsolvingtheoptimumfiltervector,whichisexpressedbyinversematrixoftheoceanenvironmentdata,isderivedinthispaper,bywhich,theoptimumfiltercanbeeventuallyexpressedasasumofseriessimplematricesofconstructedfromsensordata.Basedonthealgorithmproposedinthispaper,someexamplesofatseaexperimentareprovided.Thestronginterferencesarecancelledandtheweaksignalisemerged,evenitdidn'tappearintheconventionalbeamforming(CBF)processing.
简介:小规模的bedforms的词法特征在Dafeng潮汐的公寓上借助于声学的介绍声纳被测量,江苏在2009,并且在Jiulong河口,厦门在2010,分别地。多阀值价值方法被利用揭示bedforms是在场的词法沿着波动。获得的数据集的分析显示出那:(1)沙涟漪能有不规则的形状,并且(2)在bedform形态学的变化在一个单个潮汐的周期以内是小的,但是可能在几个潮汐的周期上重要。分数维图形和海床粗糙的variogram分析揭示了在当前的速度和海床粗糙的分数维的尺寸之间的一种重要关系的存在。作为当前的速度增加,有小规模的底部结构的一个趋势的海床粗糙增加被大规模结构正在代替。而且,大规模底部结构的表面也能由于小规模的特征的缺席变得光滑或由于附加小规模的结构的存在变得更不平。