简介：Coherentdiffractionimaging(CDI)andptychographytechniquesbypassthedifficultyofhavinghigh-qualityopticsinX-raymicroscopybyusinganumericalreconstructionoftheimagethatisobtainedbyinvertingthediffractedintensityrecordedbyacharge-coupleddevicearray.However,thereconstructionoftheimagefromtheintensitydataobtainedfromaweaklydiffractingspecimenisknowntobedifficultbecauseoftheobviousreductioninsignal-to-noiseratio(SNR).Inthiscase,thespecimenonlyslightlymodifiestheprobediffractionpattern,resultingindifficultyintheidentificationofthedetailedstructureofthespecimenfromthereconstructedimagebecauseofthepoorcontrastandsharpnessoftheimage.Toaddressthissituation,amodificationintheimageretrievalalgorithmsusedintheiterativereconstructionoftheimageissuggested.Thismodificationshoulddoublethepresenceofhighspatialfrequenciesinthediffractionpatterntoenhancethecontrastandedgedetectioninexistingimagingtechniques.

简介：Inthispaper,themorphologicalfilterbasedonparametricedgedetectionispresentedandappliedtoimagingladarimagewithspecklenoise.ThisalgorithmandLaplacianofGaussian(LOG)operatorarecomparedonedgedetection.Theexperimentalresultsindicatethesuperiorperformanceofthiskindoftheedgedetection.

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简介：Wehavedesignedanddemonstratedasimple,widefield-of-view(FOV=60°)foveatedimagingsystemutilizingadeformablemirror.Thedeformablemirrorisusedtodynamicallycorrecttheoff-axisaberrationsthatlimittheusefulFOVofthesystem.ThesystemmimicstheoperationofhumaneyethroughcreatinganimagewithvariablespatialresolutionandcanbemadesignificantlysmallerandmorecompactthanaconventionalwideFOVsystem.Experimentsshowthatthissystemcanbeusedinmanyareaswheresize,weight,anddatatransmissionbandwidtharecritical.

简介：Photoacousticophthalmoscopy(PAOM)isanovelimagingmodality,whichiscapableofnon-invasivelydetectingopticalabsorptionpropertiesintheretina.WevisualizethemicrovasculatureinretinaandchoroidinalbinomouseusingPAOMguidedbyspectral-domainopticalcoherencetomography.Sincealbinomousecharacterizesbylackingmelanininretinalpigmentepithelium(RPE),PAOMilluminationlasercanpenetratethroughtheRPEontochoroid,andconsequentlyprovidesvolumetricvisualizationofchorioretinalvasculaturesasaresultofstronghemoglobinopticalabsorption.Thehigh-qualitychorioretinalmicrovascularimagingacquiredbyPAOMimpliesitsgreatpotentialinunderstandingpathologicalmechanismsanddevelopingtherapeuticstrategiesformajorchorioretinaldiseasesthatcorrelatewithvasculardisorders.

简介：Fluorescenceliftimeimaging(FLIM)ofmodifiedhydrophobicbodipydyesthatactasfluorescentmolecularrotorsshowsthatthefluorescencelifetimeoftheseprobesisafunctionofthemicroviscosityoftheirenvironment.Incubatingcellswiththesedyes,wefindapunctateandcontinuousdistributionofthedyeincells.Theviscosityvalueobtainedinwhatappearstobeendocytoticvesiclesinlivingcellsisaround100timeshigherthanthatofwaterandofcellularcytoplasm.Time-resolvedfluorescenceanisotropymeasurementsalsoyieldrotationalcorrelationtimesconsistentwithlargemicroviscosityvalues.Inthisway,wesuccessfullydevelopapracticalandversatileapproachtomapthemicroviscosityincellsbasedonimagingfluorescentmolecularrotors.

简介：Therandomphaseerrorsoftheopticalcarriersarediscussedandcontrolledforpassivemillimeter-wavesparseaperture(PMMWSA)upconversionimaging.Atwo-channelmodelissetupforanalyzingcharacteristicsofthephaseerrors,andanactiveopticalcontroltechniquebasedonstochasticparallelgradientdecentalgorithm(SPGDcontroller)isproposedtocalibratethephaseerrors.TodemonstratethefeasibilityoftheSPGDcontroller,simulationsareperformedandanexperimentalsystemwithatwo-channelfiberarrayissetup.SimulationandexperimentresultsshowthattheSPGDcontrollercaneffectivelyandrapidlycompensatethephaseerrorsoftheopticalcarrier,andtheaccuracyofthephasecontrolissufficientforimagingsystems.

简介：Basedonthepointspreadfunctionofholographicsystem,thelateralresolutionofdigitalholographicimagingsystemwithoutanypre-magnificationisstudied.Theexpressionofresolutionlimitationofholo-graphicimagingsystemisthuspresented.Weinvestigatethepossibilitiestoimprovethelateralresolution.Thesimpleexperimentalsetupwithanoff-axisarrangementisbuilt.ByusingaU.S.AirForce(USAF)testtargetasmicroscopicobject,therecordedhologramsarereconstructeddigitallybasedontheprincipleofFresneldiffraction.Thelateralresolutionof2.76μmwithoutanypre-magnifieationisdemonstratedexperimentally,whichmatchesthetheoreticalpredictionwell.

简介：Weproposeaspeckle-reductionmethodbasedonwavelengthcharacteristicsofspeckleeffectinsyntheticapertureimagingladar(SAIL).Thereturnsignal,whichisthebackscatteringfieldwithspeckleeffectfromtheroughsurfaceoftarget,canbeintegratedoverNchirpperiodsandheterodynedetectedwithalocal-oscillatorsignal.Afterperformingimageprocessingrespectively,thefinalimagecanberegardedastheincoherentsuperpositionoftheNsub-images.Numericalsimulationsindicatetheeffectivenessofthismethod.OurresearchmayfacilitatepracticalapplicationsofSAIL.

简介：Thephotoacoustictomographybyusingthehandheldprobehasagreatpotentialinclinicalbreastimaging.However,theshapeoftheprobelimitsthechoiceoflightdeliveryinthissetup.Inthisletter,westudytwocommonlyusedilluminationtypesforhandheldprobe:bright-fieldilluminationanddark-fieldillumination.Ourresultsdemonstrateseveralparametershaveimportantimpactonthephotonfluenceindeepbreasttissue.Theresultswillhelptooptimizethedesignofthephotoacousticbreastimagingsystemwithahandheldprobe.

简介：Thisletterpresentsalabel-freebiomolecularimagingtechniquebasedonwhite-lightinterferometryandspectraldetection.Themethodmeasuresthicknesschangescausedbyspecificbindingbetweenbiomoleculestodetectthepresenceofcertainanalyte.Aspectrum-shiftingalgorithmisdevelopedtoresolvethethicknessinformationfromthespectrum.Theaxialresolutionoftheexperimentalinstrumentcanreach～1nm,therebyenablingdetectionoftraceamounts(～1ng/mm2)ofproteinsorDNA.ThisletteralsopresentstwoexperimentstoprovethefeasibilityofthemethodfordetectingproteinsandDNAwithoutfluorescentlabeling.

简介：Thisworkproposesamethodtoconcurrentlycalibratemultipleacousticspeedsindifferentmediumswithaphotoacoustic(PA)andultrasound(US)dual-modalityimagingsystem.First,physicalinfrastructureinformationofthetargetisacquiredthroughaUSimage.Then,werepeatedlybuildPAimagesaroundaspecialtargettoyieldthebestfocusedresultbydynamicallyupdatingtheacousticspeedsinadifferentmediumofthetarget.Withthesecorrectacousticpropagationvelocitiesintheaccordingmediums,wecaneffectivelyoptimizethePAimagequalityastheexperimentsproved,whichmightbenefitfutureresearchinbiomedicalimagingscience.

简介：Acompactlinescanningquasi-confocalophthalmoscope(LSO)ispresentedinthisletter.Comparedwithaconventionalscanninglaserophthalmoscope(SLO),thebench-topLSOsignificantlyreducesthesize,complexity,andcostofSLOutilitywithroutineuse.TheLSOusesonemovingparttoproducehigh-contrastandhigh-resolutionquasi-confocalimageswithnearlythesameperformanceasaSLO.TheLSOhasamoderatefieldofview(～10),whichenablesimagesofthemacula,theopticnervehead,andothertargetstobeobtainedmorequicklyandefficiently.Animageoftheopticnerveheadistakeninapreliminaryinvestigationonhumansubjects.Individualnervefiberbundlesandvesselsareresolvedatashallowdepth,withalateralresolutionofnearly10μm.

简介：Wereportonanoveldibenzothiophene-basedtwo-photonfluorescentprobeforselectivenuclearbioimaging,whichcontainsbilaterallysymmetricalpyridineringsconnectedbyacentralconjugated-bridgedibenzothiophene.Thisprobepossessesalargetwo-photonabsorptioncross-sectionof471GM,yieldsa25-foldenhancementofthefluorescencetitration,andastrongerphotostabilityfornucleilabelingthanexistingprobes.Thereal-timeobservationperiodisaminimumof1800sunderafemtosecondlaserexcitation,whichissignificantlylongerthanthatof40,6-diamidino-2-phenylindole.Theaboveresultsconfirmthatthisnovelmoleculeisasuitabletwo-photonfluorescentprobeforapplicationtonuclearbioimagingincells.

简介：Acquiringdeep-spaceimageswithhighspatialresolutionandsensitivityisimportantforspace-debrissurveillanceandearlywarning.Weproposeanovelcomputationalimaging(CI)methodforhigh-sensitivityimageacquisitioninthisletter.TheproposedapproachintroducesCIintoimageformation.Theproposedcapturingprocessconductsminormodificationsforcamerastoencodemoredesirableinformationduringcapture,whichispracticalforhardwareimplementation.Thelatentimageisreconstructedbyformulatingarecoveryproblemintoanoptimizationproblem,whichissolvedwithiterativelyreweightedleastsquaretechnique.Theexperimentalresultsclearlyshowtheeffectivenessoftheproposedmethod.

简介：DNAtetrahedralnanostructuresareconsideredtobenewnanocarriersbecausetheycanbepreciselycontrolledandholdexcellentpenetrationabilitytothecellularmembrane.AlthoughtheDNAtetrahedralnanostructureisextensivelystudiedinbiologyandmedicine,itsbehaviorinthecellswithnanoscaleresolutionisnotunderstoodclearly.Inthisletter,wedemonstratesuperresolutionfluorescenceimagingofthedistributionofDNAtetrahedralnanostructuresinthecellwithasimulatedemissiondepletion(STED)microscope,whichisbuiltbasedonaconventionalconfocalmicroscopeandcanprovidearesolutionof70nm.

简介：Eigenfacemethodusedinfacerecognitionisintroducedtoreducethepatternofinterferencefringesappearingintheabsorptionimageofcoldrubidiumatomcloudtrappedbyanatomchip.Thestandardmethodforprocessingtheabsorptionimageisproposed,andtheoriginoftheinterferencefringesisanalyzed.Comparedwiththestandardprocessingmethodwhichusesonlyonereferenceimage,wetakeadvantageoffiftyreferenceimagesandreconstructanewreferenceimagewhichismoresimilartotheabsorptionimagethanallofthefiftyoriginalreferenceimages.Thenobviousreductionofinterferencefringescanbeobtained.

简介：Wepresentatabletop-scalespotlight-modedown-lookingsyntheticapertureimagingladar(DLSAIL)demonstrator,whichisperformedbyacollimatorwith10mfocallengthtosimulatethefar-fieldopticalfield.Aspecular-pointtargetandadiffuse-reflectiontargethavebeenusedforresolutionanalysisand2Dimaging,respectively.Theexperimentalresultisinagreementwiththetheoreticaldesign.Theexperimentsetupiscapableofsimulatingarealapplicationscenarioforfurtherstudy.ThisLetterisfocusedonthepropositionandimplementationofspotlight-modeDLSAIL.

简介：Weproposeaone-dimensionalintegralimaging(1DII)displaythatconsistsofadisplaypanelandagradient-apertureparallaxbarrier.Thegradient-apertureparallaxbarrierissymmetrical,anditsslitwidthsgraduallyincreasefrombothsidestothemiddle.Theleftmostandrightmostslitsareusedtofixtheviewingangle,whereastheotherslitsareusedtoincreasetheopticalefficiency.Aprototypeoftheproposed1DIIdisplayisdeveloped.Itsopticalefficiencyishigherthanthatoftheconventionaldisplay,buttheviewinganglesarethesame.

简介：Aweakinfrared(IR)imageamplifierwithmorethan60-dBopticalgainandfrequencyup-conversionisdevelopedfromapicosecond(PS)355-nmpumpedgatedopticalparametricamplifier(OPA)inaβ-BaB2O4(BBO)crystal.TheIRimageat1064nmisamplifiedandup-convertedintothevisibleregionat532nmbyparametricamplificationandup-conversion.Withtheoptimizedopticalgain,thelowestdetectableenergyoftheimagecanbeaslowas1.8femto-Jouleperpulse,whichisthreeordersofmagnitudelowerthanthedetectionlimitofacharge-coupleddevice(CCD)camera.ThetransversalresolutionoftheOPAimagingisinvestigated,andtheapproachesforhigherdetectionsensitivityandhighertransversalresolutionareproposed.