简介:Inthispaper,themorphologicalfilterbasedonparametricedgedetectionispresentedandappliedtoimagingladarimagewithspecklenoise.ThisalgorithmandLaplacianofGaussian(LOG)operatorarecomparedonedgedetection.Theexperimentalresultsindicatethesuperiorperformanceofthiskindoftheedgedetection.
简介:Anewtechniqueispresentedtodetecttargetsunderseabackground.Focusedoninterestedareas,thespatialandfrequencydistributionsarefirststudied,thenanalyticexpressionoftargetsissetupbyleastsquaremethod(LSM).Accordingtotheshape,frequency,andanalyticexpressionoftargets,amatchedbiorthogonalwaveletisconstructedtobetterenhancetargetsandeliminatenoises.Resultsshowtheusefulnessofthismethodforsingleframedetection(signaltonoiseratioSNR≥1.25),whichprovidesabetterperformancethanclassicwaveletsandmorphologicalfiltering.
简介:Amethodofdetectingdry,icyandwetroadsurfaceconditionsbasedonscanningdetectionofsinglewavelengthbackwardpowerisproposedinthisletter.Thedetectorisusedtoreceivethebackwardscatteredpowerwhichchangeswiththeincidenceangle.Therelationshipbetweenbackwardpowerandincidenceangleisusedtofindouttheeffectiveanglerangeanddistinguishmethod.Experimentandsimulationshowthatitisfeasibletoclassifythesethreeconditionswithinincidenceangleof5.3degree.
简介:InthisLetter,aminiaturewearableRamanspectroscopysystemisdeveloped.Awearablefiber-opticprobeiemployedtohelpthestableandconvenientcollectionofRamanspectra.Anonlinearpartialleastsquaresmodebasedonamultivariatedominantfactorisemployedtopredicttheglucoselevel.Themeancoefficientsofdeterminationare0.99,0.893,and0.844fortheglucosesolution,laboratoryrats,andhumanvolunteers.ThresultsdemonstratethataminiaturewearableRamanspectroscopysystemisfeasibletoachievethenoninvasivdetectionofhumanbloodglucoseandhasimportantclinicalapplicationvalueindiseasediagnosis.
简介:Theintensityandpositionofthecouplingpointsinhighbirefringence(Hi-Bi)fiberscanbedetectedeffectivelyusingdistributedpolarizationcoupling(DPC)detection.Thedetectionsensitivitycandecreaseduetomechanicalvibrationdisturbanceandenvironmentnoise.Thus,amethodbasedonempiricalmodedecompositionisproposedtodetectweakmodecouplingpoints.Thesimulationandexperimentalresultsillustratethattheproposedmethodcansuppressthenoiseeffectivelyandimprovesensitivitysignificantly.Themethodcanidentifycouplingpointsasweakas-60dBembeddedinnoiseautomaticallyandeffectively.ThealgorithmisapplicableforDPC,andtheexperimentalsensitivityisimprovedby10dB.
简介:NonlinearopticalpropertiesofstimulatedBrillouinscattering(SBS)tosignaldetectioninwaterareanalyzed.Withthethresholdcharacteristics,SBSonlyoccurswhenthehighpowerlaserisfocusedintheSBScell.Whenthereisanobjectpresentinfrontofthefocus,itleadstolowerincidentintensityandthenSBSdoesnotoccur.ThebackwardSBSsignaldependsonthefocusinglocation.ThenonlinearopticalpropertiesofSBSprocessinthefocusingregimeareanalyzedtheoretically.Withtheobjectcomingneartothefocusingcenter,thebackwardStokessignalrisesupfromzerotoamaximum,andthengrowstosaturation.Thedelaytimeoftheechosignaltopumpsignalcangivetheobjectlocation.Inexperiment,thepeakpositionofvaryingrateofenergycangiveobjectlocation.
简介:Apiece-wisetransitiondetectionalgorithmthatperformsdisplacementmeasurementsforself-mixingsensorsisdeveloped.Thealgorithmcancorrectlydetectself-mixingfringesatalowsignal-to-noiseratiointhepresenceofdisturbanceswithoutfiltering.Displacementreconstructionsbythephaseunwrappingmethodbasedonthisalgorithmareexperimentallyvalidated,withlasersubjecttothemoderatefeedbackregime.
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.
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.
简介:Non-uniformstep-sizedistributionisimplementedforsplit-stepbasednonlinearcompensationinsingle-channel112-Gb/s16quadratureamplitudemodulation(QAM)transmission.Numericalsimulationsofthesystemincludinga20×80kmuncompensatedlinkareperformedusinglogarithmicstepsizedistributiontocompensatesignaldistortions.50%ofreductioninnumberofstepswithrespecttousingconstantstepsizesisobserved.Theperformanceisfurtherimprovedbyoptimizingnonlinearcalculatingposition(NLCP)incaseofusingconstantstepsizeswhileNLCPoptimizationbecomesunnecessarywhenusinglogarithmicstepsizes,whichreducesthecomputationaleffortduetouniformlydistributednonlinearphaseforallsuccessivesteps.