学科分类
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12 个结果
  • 简介:Inthispaper,themorphologicalfilterbasedonparametricedgedetectionispresentedandappliedtoimagingladarimagewithspecklenoise.ThisalgorithmandLaplacianofGaussian(LOG)operatorarecomparedonedgedetection.Theexperimentalresultsindicatethesuperiorperformanceofthiskindoftheedgedetection.

  • 标签: 边缘检测 图像处理 算法 成象雷达 拉普拉斯变换
  • 简介:Anewtechniqueispresentedtodetecttargetsunderseabackground.Focusedoninterestedareas,thespatialandfrequencydistributionsarefirststudied,thenanalyticexpressionoftargetsissetupbyleastsquaremethod(LSM).Accordingtotheshape,frequency,andanalyticexpressionoftargets,amatchedbiorthogonalwaveletisconstructedtobetterenhancetargetsandeliminatenoises.Resultsshowtheusefulnessofthismethodforsingleframedetection(signaltonoiseratioSNR≥1.25),whichprovidesabetterperformancethanclassicwaveletsandmorphologicalfiltering.

  • 标签: 双正交波 目标探测 海洋背景 最小二乘法 降噪 小波转换
  • 简介:Amethodofdetectingdry,icyandwetroadsurfaceconditionsbasedonscanningdetectionofsinglewavelengthbackwardpowerisproposedinthisletter.Thedetectorisusedtoreceivethebackwardscatteredpowerwhichchangeswiththeincidenceangle.Therelationshipbetweenbackwardpowerandincidenceangleisusedtofindouttheeffectiveanglerangeanddistinguishmethod.Experimentandsimulationshowthatitisfeasibletoclassifythesethreeconditionswithinincidenceangleof5.3degree.

  • 标签: 扫描检测 散射功率 路面状况 基础 传感器 入射角
  • 简介:InthisLetter,aminiaturewearableRamanspectroscopysystemisdeveloped.Awearablefiber-opticprobeiemployedtohelpthestableandconvenientcollectionofRamanspectra.Anonlinearpartialleastsquaresmodebasedonamultivariatedominantfactorisemployedtopredicttheglucoselevel.Themeancoefficientsofdeterminationare0.99,0.893,and0.844fortheglucosesolution,laboratoryrats,andhumanvolunteers.ThresultsdemonstratethataminiaturewearableRamanspectroscopysystemisfeasibletoachievethenoninvasivdetectionofhumanbloodglucoseandhasimportantclinicalapplicationvalueindiseasediagnosis.

  • 标签: 血糖水平 检测系统 拉曼光谱 微型 成年人 低血糖
  • 简介:在这封信,空间光(FSO)用有图案的调整和桶察觉的通讯被介绍在复杂、吵闹的环境改进位错误率(BER)性能。散布的光在这通讯结构被平均。秒顺序关联,小浪正规化,并且察觉到压缩在重建算法被联合。有N位的一个信号从大部分被重建很好不到N大小。没有光过滤器在传统的FSO通讯使用了的narrowband,数字模拟和实验被执行。它能也在安全通讯被要求的真实网络被采用。这提供大机会为FSO通讯的真实应用铺平道路。

  • 标签: 自由空间光通信 检测 调制 图形 比特错误率 光学滤波器
  • 简介:Theintensityandpositionofthecouplingpointsinhighbirefringence(Hi-Bi)fiberscanbedetectedeffectivelyusingdistributedpolarizationcoupling(DPC)detection.Thedetectionsensitivitycandecreaseduetomechanicalvibrationdisturbanceandenvironmentnoise.Thus,amethodbasedonempiricalmodedecompositionisproposedtodetectweakmodecouplingpoints.Thesimulationandexperimentalresultsillustratethattheproposedmethodcansuppressthenoiseeffectivelyandimprovesensitivitysignificantly.Themethodcanidentifycouplingpointsasweakas-60dBembeddedinnoiseautomaticallyandeffectively.ThealgorithmisapplicableforDPC,andtheexperimentalsensitivityisimprovedby10dB.

  • 标签: 检测灵敏度 光纤分布式 偏振耦合 环境噪声 高双折射 振动干扰
  • 简介:NonlinearopticalpropertiesofstimulatedBrillouinscattering(SBS)tosignaldetectioninwaterareanalyzed.Withthethresholdcharacteristics,SBSonlyoccurswhenthehighpowerlaserisfocusedintheSBScell.Whenthereisanobjectpresentinfrontofthefocus,itleadstolowerincidentintensityandthenSBSdoesnotoccur.ThebackwardSBSsignaldependsonthefocusinglocation.ThenonlinearopticalpropertiesofSBSprocessinthefocusingregimeareanalyzedtheoretically.Withtheobjectcomingneartothefocusingcenter,thebackwardStokessignalrisesupfromzerotoamaximum,andthengrowstosaturation.Thedelaytimeoftheechosignaltopumpsignalcangivetheobjectlocation.Inexperiment,thepeakpositionofvaryingrateofenergycangiveobjectlocation.

  • 标签: 非线性光学 散射过程 光学 物理实验
  • 简介:Apiece-wisetransitiondetectionalgorithmthatperformsdisplacementmeasurementsforself-mixingsensorsisdeveloped.Thealgorithmcancorrectlydetectself-mixingfringesatalowsignal-to-noiseratiointhepresenceofdisturbanceswithoutfiltering.Displacementreconstructionsbythephaseunwrappingmethodbasedonthisalgorithmareexperimentallyvalidated,withlasersubjecttothemoderatefeedbackregime.

  • 标签: 位移传感器 测算法 混合 分段 相位展开方法 信号噪声比
  • 简介:Aversatileandlow-costsingle-beamself-referencedphase-sensitivesurfaceplasmonresonance(SPR)sens-ingsystemwithultra-highresolutionperformanceispresented.Thesystemexhibitsaroot-mean-squarephasefluctuationof±0.0028°overaperiodof45min,i.e.aresolutionof±5.2×10~(-9)refractiveindexunits.Theenhancedperformancehasbeenachievedthroughtheincorporationofthreedesignelements:atruesingle-beamconfigurationenablingcompleteself-referencingsothatonlythephasechangeassociatedwithSPRgetsdetected,adifferentialmeasurementschemetoeliminatespurioussignalsnotrelatedtothesensorresponse,andtheeliminationofretardationdriftsbyincorporatingtemperaturestabilizationintheliquidcrystalphasemodulator.Ourdesignshouldbringthedetectionsensitivityofnon-labelingSPRbiosensingclosertothatachievablebyconventionalfluorescence-basedtechniques.

  • 标签: 等离子体 光束 灵敏度 共振传感器
  • 简介:Wepresentanovelcoherenttransceiverforopticaldifferentialphase-shiftkeying/differentialquadraturephase-shiftkeying(DPSK/DQPSK)signalsbasedonheterodynedetectionandelectricaldelayinterferometer.Asimulationframeworkisprovidedtopredictatheoreticalsensitivitylevelforthereportedscheme.Highsensitivityof-45.18dBmisachievedfor2.5-Gb/sreturn-to-zero(RZ)-DPSKsignal,andhighsensitivitiesof-36.83dBm(Itributary)and-35.90dBm(Qtributary)areobservedfor2.5-GBaud/sRZ-DQPSKsignalinback-to-backconfiguration.Transmissionforbothsignalsover100kmisalsoinvestigated.Experimentalresultsarediscussedandanalyzed.

  • 标签: DPSK信号 信号收发器 DQPSK 高灵敏度 外差探测 相干光
  • 简介:Non-uniformstep-sizedistributionisimplementedforsplit-stepbasednonlinearcompensationinsingle-channel112-Gb/s16quadratureamplitudemodulation(QAM)transmission.Numericalsimulationsofthesystemincludinga20×80kmuncompensatedlinkareperformedusinglogarithmicstepsizedistributiontocompensatesignaldistortions.50%ofreductioninnumberofstepswithrespecttousingconstantstepsizesisobserved.Theperformanceisfurtherimprovedbyoptimizingnonlinearcalculatingposition(NLCP)incaseofusingconstantstepsizeswhileNLCPoptimizationbecomesunnecessarywhenusinglogarithmicstepsizes,whichreducesthecomputationaleffortduetouniformlydistributednonlinearphaseforallsuccessivesteps.

  • 标签: 非线性补偿 步长 相干检测 传输 非均匀分布 非线性计算