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

  • 标签: 衍射成像 高对比度 标本 相干 图像重建 电荷耦合器件
  • 简介:Accuratediagnosisoftumorsneedsmuchdetailedinformation.However,availablesingleimagingmodalitycannotprovidecompleteorcomprehensivedata.Nanomedicineistheapplicationofnanotechnologytomedicine,andmultimodalityimagingbasedonnanoparticleshasbeenreceivingextensiveattention.Thisnewhybridimagingtechnologycouldprovidecomplementaryinformationfromdifferentimagingmodalitiesusingonlyasingleinjectionofcontrastagent.Inthisreview,weintroducerecentdevelopmentsinmultifunctionalnanoparticlesandtheirbiomedicalapplicationstomultimodalimagingandtheragnosisasnanomedicine.Mostofthereviewedstudiesarebasedontheintrinsicpropertiesofnanoparticlesandtheirapplicationinclinicalimagingtechnology.Theimagingtechniquesincludepositronemissiontomography,single-photonemissioncomputedtomography,computerizedtomography,magneticresonanceimaging,opticalimaging,andultrasoundimaging.

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  • 简介:Imagingsystemsinnaturehaveattractedalotofresearchinterestduetotheirsuperioropticalandimagingcharacteristics.Recentadvancementsinmaterialsscience,mechanics,andstretchableelectronicshaveledtosuccessfuldevelopmentofbioinspiredcamerasthatresemblethestructuresandfunctionsofbiologicallight-sensingorgans.Inthisreview,wediscusssomerecentprogressesinmechanicsofbioinspiredimagingsystems,includingtunablehemisphericaleyeballcameraandartificialcompoundeyecamera.Themechanicsmodelsandresultsreviewedinthisarticlecanprovideefficienttoolsfordesignandoptimizationofsuchsystems,aswellasotherrelatedoptoelectronicsystemsthatcombinerigidelementswithsoftsubstrates.

  • 标签: 成像系统 力学模型 照相机 影像系统 材料科学 电子产品
  • 简介:DearEditor,Wewouldliketopresenttheimportanceofmultimodalimaginginphoticretinopathyinacaseofphoticretinopathy.Ayoungmanpresentedwithaone-dayhistoryofleftcentralscotomaandmetamorphopsiaafterexposuretoahandheldlaserpointerbeamduringanightparty.ThelaserpointerwasaclassIIIBgreenlaserwithawavelengthof532±10nmandmaximalpower<1000mW.However.

  • 标签: MULTIMODAL IMAGING in PHOTIC RETINOPATHY FIGURE
  • 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:HL-2Atokamakisthefirstnon-circularcross-sectiontokamakwithdivertorinChina.ApartfromboundarytransportandSOLstudy,theHL-2AmajorsubjectistoinvestigatetheimprovementofconfinementwithhighparametersandalotoffrontphysicsandrelevantengineeringtechniquesbyuseofitsspecialCloseddivertorwithlargevolumeinChina.

  • 标签: 等离子体成像 约束实验 剖面控制 偏滤器
  • 简介:ApplicationofSuperresolutionTechniquestoRadarImagingA.Fanrina,F.Prodi&F.Vinelli(Alenia.UnaAziendaFinmeccanica.Radar&C2Divisio...

  • 标签: RADAR IMAGING SAR ISAR ERS- 1
  • 简介:Theplenopticcameraisasinglelensstereocamerawhichcanretrievethedirectionoflightrayswhiledetectingtheirintensitydistribution.Inthispaper,torevealmoretruthsofplenopticcameraimaging,wepresentthewavefrontanalysisfortheplenopticcameraimagingfromtheangleofphysicalopticsbutnotfromtheraytracingmodelofgeometricoptics.Specifically,thewavefrontimagingmodelofaplenopticcameraisanalyzedandsimulatedbyscalardiffractiontheoryandthedepthestimationisredescribedbasedonphysicaloptics.Wesimulateasetofrawplenopticimagesofanobjectscene,therebyvalidatingtheanalysisandderivationsandthedifferencebetweentheimaginganalysismethodsbasedongeometricopticsandphysicalopticsarealsoshowninsimulations.

  • 标签: 立体相机 成像模型 全光 波前 物理光学 标量衍射理论
  • 简介:IMAGINGOFEEGBYSPHERICALHARMONICANALYSISIMAGINGOFEEGBYSPHERICALHARMONICANALYSISYaoDezhong;YangShaoguo(Dep.ofAuto,UESTofChina,C...

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  • 简介:Computedtomography(CT),ultrasonography,sialography,and99mTcscintigraphywereappliedbeforeoperationto108patientswithparotidmasses.Theresultsofeachtechniqueandthecombinedstudyofthemwerecomparedwiththepathologicaldiagnosis.Ultrasonographywasfoundtobeaveryeffectivediagnosticaidindeterminingthepresenceofspace-occupyinglesionintheparotid.CTwasthebesttechniquetoprovideadequatelyreliableinformationsregardingthelocationofthetumorandtherelationshipbetweentumorandsurroundingtissues.Fordiagnosingthenatureoftumors,ultrasonographycombinedwithsialographywasreliable.99mTcscintigraphywasbetterthanothertechniquesindiagnosisofadenolymphoma.Thediagnosticaccuracyofcombineddiagnosis(90.7%)washigherthanthoseofultrasonography(83%),CT(80.5%),sialography(79%),and99mTcscintigraphy(13.9%)alone.Theadvantageofcombineddiagnosiswasparticularlyobviousforthediagnosisoflow-grademalignanttumors.

  • 标签: ALONE DIAGNOSTIC adequately NODULES SURROUNDING determining
  • 简介:THEORYOFTHEEEGCORTICALIMAGINGTECHNIQUESTHEORYOFTHEEEGCORTICALIMAGINGTECHNIQUESDezhongYao,BingweLuoi(DepartmentofAutomationUni...

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  • 简介:Inthelastseveralyears,therateofinnovationincardiacimagingtechniqueshasacceleratedsignificantly.Advanceshavebeenseeninall4majormodalities;echocardiography,nuclear(positronemissiontomography(PET)andsinglephotonemissioncomputedtomography(SPECT),cardiacmagneticresonanceimaging(CMR),andcomputedtomographicangiography(CTA).ThisissueofCardiovascularInnovationsandApplicationswillhighlightmanyoftheseadvances.

  • 标签: NONINVASIVE Cardiac Imaging ECHOCARDIOGRAPHY nuclear POSITRON
  • 简介:Thebrainishighlyplasticafterstrokeorepilepsy;however,thereisapaucityofbrainplasticityinvestigationaftertraumaticbraininjury(TBI).ThisminireviewsummarizesthemostrecentevidenceofbrainplasticityinhumanTBIpatientsfromtheperspectiveofadvancedmagneticresonanceimaging.Similartootherformsofacquiredbraininjury,TBIpatientsalsodemonstratedbothstructuralreorganizationaswellasfunctionalcompensationbytherecruitmentofotherbrainregions.However,thelargescalebrainnetworkalterationsafterTBIarestillunknown,andthefieldisstillshortofpropermeansonhowtoguidethechoiceofTBIrehabilitationortreatmentplantopromotebrainplasticity.Theauthorsalsopointoutthenewdirectionofbrainplasticityinvestigation.

  • 标签: 磁共振成像 可塑性 大脑 外伤 创伤性脑损伤 结构重组
  • 简介:Thispapercombinescompressedsensing(CS)imagingtheoryandrangemigrationalgorithm(RMA),andthenproposesanear-fieldthree-dimensional(3-D)imagingapproachforjointhigh-resolutionimagingandphaseerrorcorrection.Firstly,asparsemeasurementmatrixconstructionmethodbasedonalogisticsequenceisproposed,whichconductsnonlineartransformationforthedeterminedlogisticsequence,makingitobeyuniformdistribution,thenconductssignfunctionmapping,andgeneratesthepseudorandomsequencewithBernoullidistribution,thusleadingtogoodsignalrecoveryunderdown-samplingandeasyavailabilityforengineeringrealization.Secondly,incombinationwiththeRMAimagingapproach,thedictionarywithallsceneinformationandphaseerrorcorrectionisconstructedforCSsignalrecoveryanderrorcorrection.Finally,thenon-quadraticsolutionmodeljointingimagingandphaseerrorcorrectionbasedonregularizationisbuilt,anditissolvedbytwosteps—theseparablesurrogatefunctionals(SSF)iterativeshrinkagealgorithmisadoptedtorealizetargetscatteringestimate;theiterationmodeisadoptedforthecorrectionofthedictionarymodel,soastoachievethegoaloferrorcorrectionandhighly-focusedimaging.Theproposedapproachprovestobeeffectivethroughnumericalsimulationandrealmeasurementinanechoicchamber.Theresultsshowthat,theproposedapproachcanrealizehigh-resolutionimaginginthecaseoflessdata;thedesignedmeasurementmatrixhasbetternon-coherenceandeasyavailabilityforengineeringrealization.Theproposedapproachcaneffectivelycorrectthephaseerror,andachievehighly-focusedtargetimage.

  • 标签: NEAR-FIELD 3-D imaging compressed SENSING (CS)
  • 简介:AbstractImportance:The process of brain development in children with developmental delay is not well known. Amide proton transfer-weighted (APTw) imaging is a novel molecular magnetic resonance imaging (MRI) technique that can noninvasively detect cytosolic endogenous mobile proteins and peptides involved in the myelination process, and may be useful for providing insights into brain development.Objective:To assess the contribution of amide proton transfer-weighted (APTw) imaging and magnetization transfer (MT) imaging to the evaluation of children with developmental delay (DD).Methods:Fifty-one patients with DD were recruited to this study. The patients were divided into two groups according to the state of myelination assessed on conventional magnetic resonance imaging (MRI). Thirty patients (10 girls, 20 boys; age range: 1-8 months; median age: 4 months) in group A showed delayed myelination on MRI , while 21 patients (3 girls, 18 boys; age range: 12-36months; median age: 25months) in group B showed normal myelination on MRI. Fifty-one age- and sex-matched children with normal developmental quotient (DQ) and normal MRI appearance were recruited as normal controls. Three-slice APTw/MT axial imaging was performed at the level of the centrum semiovale, the basal ganglia and the pons. Quantitative data of the MT ratio (MTR) and APTw were analyzed for multiple brain regions. Independent-sample t-tests were used to compare differences in APTw and MTR signals between the two DD groups and normal controls. Analysis of Covariance was conducted to correct the statistical results. The level of statistical significance was set to P < 0.05.Results:For group A, the MTR values were lower in all regions (P = 0.004-0.033) compared with the normal controls, while the APTw values were higher in the pons, middle cerebellar peduncle, corpus callosum, frontal white matter, occipital white matter and centrum semiovale (P = 0.004-0.040 ). For Group B, the MTR values were slightly reduced, and the APTw values were slightly increased compared with the normal controls, but the differences were not statistically significant (P > 0.05).Interpretation:For DD patients showing signs of delayed myelination on MRI, MTR and APTw imaging can help to diagnose myelination delay by quantifying semi-solid macromolecules and cytosolic endogenous mobile proteins and peptides at a molecular level, providing a new method for comprehensive evaluation of DD. For DD patients with normal myelination on MRI, the clinical values of MTR and APTw imaging remain to be explored.

  • 标签: Children Myelination Developmental delay Amide proton transfer Magnetization transfer
  • 简介:RecentnovelapproachesinmyocardialperfusionsinglephotonemissionCT(SPECT)havebeenfacilitatedbynewdedicatedhigh-efficiencyhardwarewithsolid-statedetectorsandoptimizedcollimators.Newprotocolsincludeverylow-dose(1mSv)stress-only,two-positionimagingtomitigateattenuationartifacts,andsimultaneousdual-isotopeimaging.Attenuationcorrectioncanbeperformedbyspecializedlow-dosesystemsorbypreviouslyobtainedCTcoronarycalciumscans.HybridprotocolsusingCTangiographyhavebeenproposed.Imagequalityimprovementshavebeendemonstratedbynovelreconstructionsandmotioncorrection.FastSPECTacquisitionfacilitatesdynamicflowandearlyfunctionmeasurements.Imageprocessingalgorithmshavebecomeautomatedwithvirtuallyunsupervisedextractionofquantitativeimagingvariables.Thisautomationfacilitatesintegrationwithclinicalvariablesderivedbymachinelearningtopredictpatientoutcomeordiagnosis.Inthisreview,wedescribenewimagingprotocolsmadepossiblebythenewhardwaredevelopments.WealsodiscussseveralnovelsoftwareapproachesforthequantificationandinterpretationofmyocardialperfusionSPECTscans.

  • 标签: MYOCARDIAL PERFUSION imaging single PHOTON EMISSION
  • 简介:Ghostimagingcouldbeusedtomakeaquickidentificationoforthogonalobjectsbymeansofphotocurrentcorrelationmeasurements.Inthispaper,weextendthemethodtoidentifynonorthogonalobjects.Inthemethod,anobjectisilluminatedbyonephotonfromanentangledpair,andtheotheroneisdiffractedintoaparticulardirectionbyapre-establishedmultiple-exposurehologramintheidlerarm.Bythecorrelationmeasurements,thenonorthogonalobjectinthesignalarmcouldbediscriminatedwithinaveryshorttime.Theconstraintsfortheidentificationofnonorthogonalobjectsarepresented,whichshowthatthenonorthogonalobjectscanbediscriminatedwhentheoverlappingportionbetweenanytwoobjectsislessthanhalfofalltheobjectsintheset.Thenumericalsimulationsfurtherverifytheresult.

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  • 简介:常规时间成像技术不能够生产精确地震成像在Tarim盆的山前面表面下,中国。他们的想象的结构导致了以前钻失败的某专业,忍受他们的结构的闭合有的坏名声车轮和他们的结构的高度有弹簧。这篇文章首先列出成像挑战,并且解释在一图解时间成像技术为什么在这个区域失败。然后通过一系列真实数据例子,当时,它表明那在那里存在侧面的速度变化,深度成像是唯一的答案在这个区域处理成像挑战。为wavefield的复杂性的深度成像报道,因此生产优异、地质的嘴巧的图象。在适当地执行深度成像的核心任务是造速度模型。这篇文章强调一些主要方面在这方面。

  • 标签: 地震成像 塔里木盆地 复杂构造 深度成像 成像技术 横向速度