学科分类
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11 个结果
  • 简介:Severalfeaturesofretinalvesselscanbeusedtomonitortheprogressionofdiseases.Changesinvascularstructures,forexample,vesselcaliber,branchingangle,andtortuosity,areportentsofmanydiseasessuchasdiabeticretinopathyandarterialhypertension.Thispaperproposesanautomaticretinalvesselsegmentationmethodbasedonmorphologicalclosingandmulti-scalelinedetection.First,anilluminationcorrectionisperformedonthegreenbandretinalimage.Next,themorphologicalclosingandsubtractionprocessingareappliedtoobtainthecruderetinalvesselimage.Then,themulti-scalelinedetectionisusedtofinethevesselimage.Finally,thebinaryvasculatureisextractedbytheOtsualgorithm.Inthispaper,forimprovingthedrawbacksofmulti-scalelinedetection,onlythelinedetectorsat4scalesareused.Theexperimentalresultsshowthattheaccuracyis0.939forDRIVE(digitalretinalimagesforvesselextraction)retinaldatabase,whichismuchbetterthanothermethods.

  • 标签: 视网膜血管 视网膜图像 分割方法 船只 在线检测 OTSU算法
  • 简介:Inordertoslovethelarge-scalenonlinearprogramming(NLP)problemsefficiently,anefficientoptimizationalgorithmbasedonreducedsequentialquadraticprogramming(rSQP)andautomaticdifferentiation(AD)ispresentedinthispaper.Withthecharacteristicsofsparseness,relativelylowdegreesoffreedomandequalityconstraintsutilized,thenonlinearprogrammingproblemissolvedbyimprovedrSQPsolver.Inthesolvingprocess,ADtechnologyisusedtoobtainaccurategradientinformation.Thenumericalresultsshowthatthecombinedalgorithm,whichissuitableforlarge-scaleprocessoptimizationproblems,cancalculatemoreefficientlythanrSQPitself.

  • 标签: 简化序列二次规划 优化算法 自动微分法 大规模非线性规划
  • 简介:ThispaperpresentstwodifferentalgorithmsthatderivethecohesionstructureintheformoflexicalchainsfromtwokindsoflanguageresourcesHowNetandTongYiCiCiLin.There-searchthatconnectsthecohesionstructureofatexttothederivationofitssummaryisdisplayed.Anovelmodelofautomatictextsummarizationisdevised,basedonthedataprovidedbylexicalchainsfromoriginaltexts.Moreover,theconstructionrulesoflexicalchainsaremodifiedaccord-ingtocharacteristicsoftheknowledgedatabaseinordertobemoresuitableforChinesesumma-rization.EvaluationresultsshowthathighqualityindicativesummariesareproducedfromChi-nesetexts.

  • 标签: 文本自动摘要 织构 内聚力 词汇链
  • 简介:ThepaperpresentsanalgorithmofautomatictargetdetectioninSyntheticApertureRadar(SAR)imagesbasedonMaximumAPosteriori(MAP).Thealgorithmisdividedintothreesteps.First,itemploysGaussianmixturedistributiontoapproximateandestimatemulti-modalhistogramofSARimage.Then,basedontheprincipleofMAP,whenaprioriprobabilityisbothunknownandlearnedrespectively,thesamplepixelsareclassifiedintodifferentclassesc={target,shadow,background}.Last,itcomparestheresultsoftwodifferenttargetdetections.Simulationresultspreferablyindicatethatthepresentedalgorithmisfastandrobust,withthelearnedaprioriprobability,anapproachtotargetdetectionisreliableandpromising.

  • 标签: SAR 人造光圈雷达 图象处理 目标探测 Gaussian分布
  • 简介:Beingdirectedagainettwokinksofnoiseinopticalfibersensors,asim-pleandeffectivemethodofautomaticcompensationforopticalfibersensorsispresented.Notonlytheunstabilityeffectoflightsource,butalsozerodriftofphotoelectronicde-vices,canbeeliminatedorenormouslyrestranedwiththeaidofthismethod.Inanotherway,byusingsingle-chipmrcrocomputer,theopticalfibersensorsystemfabricatediscaonnetedtoacopmuternetworkstorealizeanautomaticcompensation.

  • 标签: 自动补偿 计算机网络 自校正 光纤传感器
  • 简介:ThepaperaddressestheproblemoftargetrecognitionusingHigh-resolutionRadarRangeProfiles(HRRP).Anovelapproachoffeatureextractionanddimensionreductionbasedonextendedhighordercentralmomentsisproposedinordertoreducethedimensionofrangeprofiles.FeaturesextractedfromradarHRRPsarenormalizedandsmoothed,andthencomparativeanalysisofthesimilarapproachesisdone.Therangeprofilesareobtainedbystepfrequencytechniqueusingthetwo-dimensionalbackscattersdistributiondataoffourdifferentaircraftmodels.Thetemplatematchingmethodbynearestneighborrules,whichisbasedonthetheoryofkernelmethodsforpatternanalysis,isusedtoclassifyandidentifytherangeprofilesfromfourdifferentaircrafts.Numericalsimulationresultsshowthattheproposedapproachcanachievegoodperformanceofstability,shiftindependenceandhigherrecognitionrate.Itishelpfulforreal-timeidentificationandtheengineeringimplementsofautomatictargetrecognitionusingHRRP.Thenumberofrequiredtemplatescouldbereducedcon-siderablywhilemaintaininganequivalentrecognitionrate.

  • 标签: 目标识别雷达 高分辨距离像 高阶 矩特征 模板匹配法 高分辨率雷达
  • 简介:UseSingle-chipComputertoRealizeAutomaticCompensationforOpticalFiberSensors①WANGShouyu,TIANGuangyun,YINGuiliang(YanshanUnivers...

  • 标签: AUTOMATIC COMPENSATION COMPUTER Network Self-correction OPTICAL
  • 简介:Theneedforwide-bandclockanddatarecovery(CDR)circuitsisdiscussed.A2Gbpsto12Gbpscontinuous-rateCDRcircuitemployingamulti-modevoltage-controloscillator(VCO),afrequencydetector,andaphasedetector(FD&PD)isdescribed.Anewautomaticfrequencybandselection(FBS)withoutexternalreferenceclockisproposedtoselecttheappropriatemodeandalsosolvetheinstabilityproblemwhenthecircuitispoweringon.Themulti-modeVCOandFD/PDcircuitswhichcanoperateatfull-rateandhalf-ratemodesfacilitateCDRwithsixoperationmodes.TheproposedCDRstructurehasbeenmodeledwithMATLABandthesimulatedresultsvalidateitsfeasibility.

  • 标签: GBPS 波段选择 CDR 动频率 宽范围 电压控制振荡器
  • 简介:ThispaperproposesaPCAandKPCAself-fusionbasedMSTARSARautomatictargetrecognitionalgorithm.Thisalgorithmcombinesthelinearfeatureextractedfromprincipalcomponentanalysis(PCA)andnonlinearfeatureextractedfromkernelprincipalcomponentanalysis(KPCA)respectively,andthenutilizestheadaptivefeaturefusionalgorithmwhichisbasedontheweightedmaximummargincriterion(WMMC)tofusethefeaturesinordertoachievebetterperformance.Thelinearregressionclassifierisusedintheexperiments.Theexperimentalresultsindicatethattheproposedself-fusionalgorithmachieveshigherrecognitionratecomparedwiththetraditionalPCAandKPCAfeaturefusionalgorithms.

  • 标签: 目标识别算法 KPCA MSTAR SAR 非线性特征提取 核主成分分析
  • 简介:AmeasurementsystemwiththeCCDmatrixandcomputersystemisdesignedtotestthe2Dsizeofanyshapeworkpiecesautomatically.Inaddition,thesystemadoptsthemethodoftherelativemeasurementwhichincreasestheprecisionandthevelocity.Moreimportantly,theprecisioncan'tbechangedwiththeconditionsofthetemperatureandairpressure.Theexperimentsshowthattherelativeprecisionof0.0029andtheabsoluteprecisionof2.97μmareobtained.Theinstrumentmaybeusedintheproductlineandmakethetestingonlinepossible.

  • 标签: CCD矩阵 摄影目标 计算机 电荷耦合器件
  • 简介:Thisletterintroducesa4thorderactiveRCcomplexfilterwith1.5MHzcenterfrequencyand1MHzbandwidth.Thetotalharmonicdistortionofthefilterislessthan–60dBandtheimagerejectionratioisgreaterthan60dB.Anoveltechniqueisalsoproposedinthislettertoautomaticallyadjustthevariationofthetimeconstant.Theadvantagesoftheproposedmethodareitshighprecisionandsimplicity.Using5bitscontrolwords,thetuningerrorislessthan±1.6%.

  • 标签: 自动旋转系统 计算机技术 设计方案 网络技术