外文资料-- Simulation Study of Electrode System Optimization in Electrical Impedance Tomography.PDF外文资料-- Simulation Study of Electrode System Optimization in Electrical Impedance Tomography.PDF

收藏 分享

资源预览需要最新版本的Flash Player支持。
您尚未安装或版本过低,建议您

CorrespondingauthorShaHong.emailsha_hong_2000yahoo.comSimulationStudyofElectrodeSystemOptimizationinElectricalImpedanceTomographyWangYan,RenChaoshi,ZhaoShu,WangLei,ShaHongInstituteofBiomedicalEngineeringChineseAcademyofMedicalSciencesPekingUnionMedicalCollegeTianjin,China.E-mailsarahyky163.cmAbstractElectrodeliesinthefrontoftheElectricalimpedancetomographyEITsystemandcontactswithhumanbodydirectly.ItisoneofthemostsensitiveandthepivotalpartsofEITsystem.Thetypeandtheconfigurationofelectrodesysteminfluencethereconstructionimagegreatly,especiallyforthecentralareaofbody,wherethemeasurementsensitivityisverylow.Asimulationplatformisdevelopedtooptimizetheelectrodestructureparameterbasedonthecoerciveequipotentialnodesmodelfortheimagingobjectofthedeepareaofbody.Theinfluencesonthemeasurementsensitivityandtheimagereconstructionqualityhavebeenstudiedusingdifferentelectrodetypesandconfigurations.Thesimulationresultssuggestthatoptimalselectionofelectrodetypesandconfigurationscanhelpfullyincreasetheimagequalityandmeasurementsensitivityoftheimageespeciallyincentralarea.SeveraltypeandconfigurationparameterofEITelectrodethatfitforcentralobjectimagingarealsopresented.Keywords-EIT;electrodesystem;reconstructionquality;measurementsensitivity;simulationevaluationI.0BINTRODUCTIONEITisoneoftheimportantresearchtopicsintoday’sbiomedicalengineering[1]-[3].EITelectrodearrayisoneofthemostsensitiveandthepivotalpartsofEITsystem.UsuallytenormoreelectrodesareusedinEITsystem.TheelectrodearrayliesinthefrontoftheEITsystemandcontactswithhumanbodydirectly.Thestructureandperformanceoftheelectrodesystemgreatlyinfluencetheoriginalinformationextraction,realtimepropertyofthesystem,imageresolvingpower,andespeciallytheinformationextractionfromcentralarea,wheretheEITmeasurementsensitivityispoor.Intheearlyoptimumstudyofelectrodeconfiguration,itiswidelyacceptedthatcurrentexcitationelectrodesshouldbeaslargeaspossiblewhilethevoltagemeasuringelectrodesarerequiredassmallaspossible[4].PingHua[5]studiedtheinfluenceofcontactimpedancebetweenelectrodeandskin,andshowedthatthebesteffectcanbeobtainedwhenthetotalwidthofelectrodearrayisabout80-90oftheimagedarea’sperimeter.E.J.Woo[6]usedannularcurrentandvoltageelectrodescovering90ofthesurface.P.A.T.Pinheiro[7]reportedthattheoptimumareaunderneaththeelectrodesis80oftheoverallboundaryareafortheadjacentpatternsand60fortheoppositeones.WangChaoetal[8][9]carriedonthesimulationresearchontheinfluenceofelectrodewidthusingthecoerciveequipotentialnodefiniteelementmethodFEMmodel,andshowedthatthebesteffectwasobtainedwhentheoverlayrateofelectrodesis57.1.AlthoughcontinuousprogressesonthechoiceofelectrodestructureparameterinEIThavebeenmade,thecompleteandsatisfactoryresulthasnotbeenseensofar.Inpractice,thedesignofEITelectrodestructureandparameterisstillbasedonexperience.AmongEITelectrodes,thecompoundelectrodehasmorecomplexstructure.FourparametersofthecompoundelectroderestricteachotherandtheirinfluenceonEITsystemaremuchcomplex.Theinfluencesofallparametersshouldbeconsideredcomprehensively.Usingonlytheoverlayrateofelectrodesisnotagoodwaytodealwiththecompoundelectrodeoptimizingdesign.InEITmeasurement,thecentralarea,correspondingtodeepareaofbody,isoftentheregionofinterest.Butthemeasurementsensitivityofthecentralareaisrelativelylowerandtheimagequalityisrelativelypoor.HowtoraisethemeasurementsensitivityandimprovetheimagequalityofthecentralareaisakeyprobleminEITmeasurement.TheexcitationpatternisalsoanimportfactorinEITmeasurement.Adjacentexcitationhasmoreindependentmeasurenumber.Oppositeexcitationpatternhaslessindependentmeasure,butthefielddistributionismorereasonablethanthatinadjacentpattern.Inthispaper,asimulationstudyofEITelectrodestructureandparameterdesignaimingattheimagingobjectofcentralareaispresented.Usingthecoerciveequipotentialnodemodelforcompoundelectrode[10],asimulationplatformisdevelopedtocarryouttheoptimizingdesignoftheelectrodesystem.Basedonthemodelandtheplatform,theinfluencesoftheelectrodenumber,type,configuration,andexcitationpatternoftheelectrodesystemonthemeasurementsensitivityandtheimagereconstructionqualityhavebeenstudied.ThesimulationstudyofEITimagingwithdifferentdepthsofimagingobjecthasbeenmadewithequipotentialbackprojectionalgorithm.978-1-4244-4713-8/10/25.002010IEEEII.1BMETHODA.4BFiniteElementModelforComplexElectrodesElectrodeplatesinroundorrectangleshapeareusuallyusedinEIT.Theprojectionsofbothelectrodesonthetomogramplanearealineandthelengthofthelineequalstothewidthoftheelectrodes,calledlineelectrode,asshownin1and2ofFig.1.Forthecompoundelectrodewithacomplexstructure,theprojectiononthetomogramplaneconsistsof3lines,asshownin3and4ofFig.1.Theexcitationelectrodeconsistsoftwolines,jinFig.1,ontheleftandtherightrespectively,andthemiddleline,cinFig.1,representsthemeasurementelectrode.Thereare4structureparametersforthecompoundelectrodeFig.1,theexcitationelectrodewidthj,themeasurementelectrodewidthc,thespacebetweentheexcitationelectrodeandthemeasurementelectrodeb,andthedistancebetweentwoadjacentcompoundelectrodesa.EachofthemispresentedbythecountofFEMnodes.ForanEITelectrodesystemwithcertainboundarysuchas256nodesinthisstudy,whentheelectrodenumbers32hereandelementsdividedinFEM1210herearedetermined,thesumofelectrodewideandthespacebetweenadjacentelectrodesisfixedtoo8here.Figure1.ThelineelectrodeandcompoundelectrodeinEITAfiniteelementmethodFEMofthecompoundelectrodeusingcoerciveequipotentialnodemodelhasusedtostudytheEITelectrodestructureparameteroptimizing[10].B.5BEstimateFunctionsInordertoestimatetheinfluencesofelectrodestructureandparametersonthemeasurementsensitivityandtheimagereconstructionqualityinEIT,themeasurementsensitivityfunctionSandtheimagereconstructionqualityfunctionDaredefinedrespectivelyasfollows.110BThemeasurementsensitivityfunctionS10011010∑∑−−NiMjijSNMSHereMisthemeasurementnumbercorrespondingofonecurrentexcitation.Nisthenumberofcurrentexcitations.Sijdenotesthemeasurementsensitivityforjthmeasurementinithcurrentexcitation0101σσ−−VVSijSijshowsthatthevoltageofthemeasurementelectrodechangesfromV0toV1whiletheconductanceofacertainregioninthemeasuredfieldchangesfromσ0toσ1.SistheaveragesensitivityofallNtimesofexcitations.Itonlydependsontheelectricfielddistributionduetotheconductancechangeofthemeasuredregion,andisindependentofimagereconstructionalgorithmandhardwareerrorssupposethatsignaltonoiseratioofeachelectrodeisfixed.ThebiggertheSis,thehigherthemeasurementsensitivityis.211BTheImageReconstructionQualityFunctionD10025511−∑MpSpGpGiMD(p1,2,M)HereMisthenumberofalltheelementsdividedintheimagingregion.Gspisthegrayvalueofpthelementintheimagingmodel.Gipisthegrayvalueofpthelementinthereconstructedimage.Dshowsthenormalizedaveragevalueofthegreyscaledifferencesbetweenthereconstructedimageandtheimagingmodelofeachelementintheimagingregion.Dsensitivelyreflectsthereconstructedimagequality.UsingD,thedifferencebetweenthereconstructedimageandtheimagingmodelcanbeevaluatedwithoutanyimageprocessing.ThesmallerDis,thelessthedifferencebetweenthereconstructedimageandtheimagingmodelis,thehigherthereconstructedimagequalityis.C.6BImagingModelsInthestudyofthispaperthetotalnumberoffiniteelementsis1210,including734nodes.Thereare256nodesonthecircumferenceofthemeasuredfield.6imagingmodelscorrespondingtodifferentmeasurementdepthhavebeenusedFig.2.Theimagedobjectmovesfromtheboundarytothecentralareafrommodel1to6,andthemodel6istheimagedobjectofcentralarea,correspondingtodeepareaofbody.III.2BSIMULATIONEXPERIMENTANDRESULTA.7BEffectsofElectrodeNumberEITsystemwith8,16,32,64,128and256pointelectrodesareusedrespectivelyforstudy.TheestimateresultsusingfunctionsDfor6imagingmodelsinFig.1isshowninFig.3.Theimagingresultsofmodel3andmodel6areshowedinFig.4.B.EffectsofElectrodeTypeandStructureParameterThereconstructionimageshavebeenmadeusingthecoerciveequipotentialnodemethodforlineelectrodeandcompoundelectrode.Somecomparisonstudiesoftheparameterinfluencesonmeasurementsensitivityandreconstructionqualitybetweenlineelectrodeandcompoundelectrodehavebeencarriedout.Figure2.ImagingmodelsofdifferentdepthsFigure3.TheeffectsofelectrodenumberonimagequalityFigure4.Imagingresultswithdifferentelectrodenumberformodel3and6Thetotalwidthofbothlineelectrodeandcompoundelectrodearesettothesame.Asanexample,thewidthoflineelectrodeis5FEMnodes,whilecompoundelectrodehas3cases,inwhichthetotalwidthsofthemarealso5FEMnodes.Thefirsta3,j1,c3andb0,theseconda3,j1,c1andb1,thethirda3,j2,c1andb0.Theothercasesofdifferentwidthhavesimilarresult.ThefunctionsSandDofthereconstructionimagescorrespondingtoimagemodel6andmodel3respectivelyhavebeencalculatedandshownintableIandtableII.C.9BEffectofExcitationPatternTheeffectofexcitationpatternofEITonthereconstructedqualityandthemeasurementsensitivityhasinvestigated.Theexcitationpattern,whichdetermineshowthecurrentflowsintotheinterestingarea,influencesthedistributionofelectromagneticfielddirectly.Inthisstudy,theadjacent,intervalandoppositeexcitationmodeareused.Taken32electrodesasanexample,theexcitationcurrentisappliedbytwoelectrodes,andtheintervaloftheelectrodesischangedfrom1to16.Whentheintervalis1,itisadjacentexcitation.Andwhentheintervalis16,itisoppositeexcitation.Othercasesarecalledintervalexcitation,Fig.5.Thereconstructionresultsof32electrodesatintervalsof1,4,8,12,16electrodesrespectivelyhavebeenmadewiththeimagemodelsshowninFig.2.TheeffectsofexcitationpatternonimagequalityandmeasurementsensitivityhavebeenshowninFig.6andFig.7.TABLEI.COMPARISONOFLINEELECTRODEANDCOMPOUNDELECTRODEFORMODEL6TABLEII.COMPARISONOFLINEELECTRODEANDCOMPOUNDELECTRODEFORMODEL3Figure5.Adjacentexcitation,intervalexcitationandoppositeexcitationpatternFigure6.EffectsofexcitationpatternonimagequalityElectrodeTypeandStructureParameterDSLineelectrode5nodeswide18.7060.003979a3j1c3b018.5840.003897a3j1c1b118.5760.003889a3j2c1b018.5890.003977ElectrodetypeandstructureparameterDSLineelectrode5nodeswide14.3560.001871a3j1c3b014.6100.001836a3j1c1b114.4750.001831a3j2c1b014.4510.001875510152025308163264128256D[[[[[[electrodecountmodel6model5model4model3model2model100.0050.010.0150.020.0251481216S[[[Intervalofcurrentelectrodesmodel6model5model4model3model2model1Figure7.EffectsofexcitationpatternonmeasurementsensitivityIV.3BRESULTSANDDISCUSSIONSFromFig3andFig4,itisshowedthatfornoncentralimagingobject,smallerelectrodenumberwillincreasethereconstructionerror.Butwhentheelectrodenumberturneduptoacertainextent,theimprovementbecamelesssignificant.Theimagequalityisalmostthesamewhenelectrodenumberismorethan64inthestudycondition.Fortheimagedobjectofcentralarea,especiallyformodel6,reconstructionqualityisverysimilar.Whentheelectrodenumberenlargedto128and256,theimagingqualityturnedabitworse.Thissuggeststhatforcentralobject,biggerelectrodenumbercannotbringbetterimagingquality.Inthispaper,the32and64electrodesystemisbetter.IntableI,fortheimagingobjectinthecentralarea,compoundelectrodehashigherimagequality,thanlineelectrode.AndintableII,fortheimagingobjectatsemi-radius,theeffectoflineelectrompoundelectrodeishelpedtoimproveimagequalityofthecentralarea.ThemeasurementsensitivitySoflineelectrodearealmostthesamewiththatofthethirdcaseofcompoundelectrode,andbetterthantheothertwocases,inbothtableIandII.Itmeansthat,ifthetotalelectrodewidthisfixed,themeasurementsensitivityisbetterwhenlargeexcitationelectrodehasbeenused.FromFig.6and7,itcanbeseenthatforeverydepthsofimagingobject,imagequalityturnsworseatintervalsofbiggerdistance,andthemeasurementsensitivityisincreasedsignificantly.Itisthesuggestionthatoptimizingofelectrodesystemaccordingtotheapplicationrequirement,forexampletheimagingobjectofdifferentdepthsandthedifferentexcitationpattern,isveryimportant.ThesimulationstudyofEITelectrodestructureandparameterdesignishelpfultogethighermeasurementsensitivityandgoodimagequality.12BREFERENCES[1]BarberD.C.andBrownB.H.,“Appliedpotentialtomography”,J.Phsy.ESci.instrum.,1984,17,pp.723-733.[2]BrownBH,“Medicalimpedancetomographyandprocessimpedancetomographyabriefreview”,Meas.Sci.Technol.2001,12,pp.991-996.[3]RenChaoshi,“Bioimpedancemeasurementtechnology.ChinaMedicalDeviceInformation”,2004,10,1,pp.21-25.[4]Paulson.K.,“Parallelalgorithmsforthree-dimensionalelectricalimpedancetomography”,PhD.Thesis,SchoolofComputingandMathematicalSciences,OxfordBrooksUniversity,1992.[5]PingHua,EungJeWoo,JohnGWebster,andWillisJ.Tompkins.“Usingcompoundelectrodesinelectricalimpedancetomography”,IEEETrans.Biome.Engn.,1993,40,1,pp.29-34[6]E.J.Woo,p.Hua,J.G.Websteretal.,“Finite-elementmethodinelectricalimpedancetomography”.Med.Bio.Eng.Comput.1994,32,pp.530-536.[7]P.A.T.Pinheiro,W.W.LohandF.J.Dickin.,“Optimalsizedelectrodesforelectricalresistancetomography”.ElectronicsLetters1998,34,1,pp.69-70[8]WangChao,WangHuaxiang,“Optimizingdesignofelectrodeconstructioninmedicalelectricalimpedancetomographysystem”.Journalofthefourthmilitarymedicaluniversity,2001,22,1,pp.78-80.[9]WangHuaxiang,WangChao,YinWuliang,“OptimumdesignofthestructureoftheelectrodeforamedicalEITsystem”,Meas.Sci.Technol.2001,12,pp.1020-1023.[10]WangYan,ShaHong,RenChaoshi,“Optimumdesignofelectrodestructureandparametersinelectricalimpedancetomography”,Physiol.Meas.2006,27,pp.291–306.51015202530351481216D[[[[Intervalofcurrentelectrodesmodel6model5model4model3model2model1
编号:201311062134403280    类型:共享资源    大小:385.42KB    格式:PDF    上传时间:2013-11-06
  
1
关 键 词:
外文资料 外文翻译
  人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
关于本文
本文标题:外文资料-- Simulation Study of Electrode System Optimization in Electrical Impedance Tomography.PDF
链接地址:http://www.renrendoc.com/p-93280.html

当前资源信息

5.0
 
(3人评价)
浏览:112次
a****上传于2013-11-06

官方联系方式

客服手机:17625900360   
2:不支持迅雷下载,请使用浏览器下载   
3:不支持QQ浏览器下载,请用其他浏览器   
4:下载后的文档和图纸-无水印   
5:文档经过压缩,下载后原文更清晰   

相关资源

  • 人教版高三英语一轮复习练习选修六 Unit 3(附答案)+中学生作文:青灯不灭人教版高三英语一轮复习练习选修六 Unit 3(附答案)+中学生作文:青灯不灭

  • 外研版高考英语一轮复习必修24Module4知能演练(有答案)+高三作文:怪兽外研版高考英语一轮复习必修24Module4知能演练(有答案)+高三作文:怪兽

  • 外研版高考英语一轮复习必修2 3 Module3知能演练(附答案)+关于网络的作文:身在此山  亦识面目外研版高考英语一轮复习必修2 3 Module3知能演练(附答案)+关于网络的作文:身在此山  亦识面目

  • 外研版高考英语一轮复习必修26Module6知能演练(附答案)+关于网络的作文:固守一片净土外研版高考英语一轮复习必修26Module6知能演练(附答案)+关于网络的作文:固守一片净土

  • 人教版高三英语一轮复习练习选修八Unit1(有答案)+中学生作文:方寸之间见天地精华人教版高三英语一轮复习练习选修八Unit1(有答案)+中学生作文:方寸之间见天地精华

  • 外研版高考英语一轮复习必修2 5 Module5知能演(含答案)+高三作文:育花吟外研版高考英语一轮复习必修2 5 Module5知能演(含答案)+高三作文:育花吟

  • 外研版高考英语一轮复习必修2 5 Module5知能演(含答案)+高三作文:如果明天永远不来外研版高考英语一轮复习必修2 5 Module5知能演(含答案)+高三作文:如果明天永远不来

  • 人教版高三英语一轮复习练习选修六 Unit 4(有答案)+中学生作文:心之所向人教版高三英语一轮复习练习选修六 Unit 4(有答案)+中学生作文:心之所向

  • 人教版高三英语一轮复习练习选修六Unit2(含答案)+高三作文:家教家风事体大人教版高三英语一轮复习练习选修六Unit2(含答案)+高三作文:家教家风事体大

  • 人教版高三英语一轮复习练习选修六Unit1(带答案)+高三作文:读万卷书行万里路人教版高三英语一轮复习练习选修六Unit1(带答案)+高三作文:读万卷书行万里路

  • 外研版高考英语一轮复习必修2 3 Module3知能演练(附答案)+高三作文:母亲放羊外研版高考英语一轮复习必修2 3 Module3知能演练(附答案)+高三作文:母亲放羊

  • 人教版高三英语一轮复习练习选修八Unit5(有答案)+高三作文:绽放生命真我的风采人教版高三英语一轮复习练习选修八Unit5(有答案)+高三作文:绽放生命真我的风采

  • 人教版高三英语一轮复习练习选修八Unit4(附答案)+高三作文:选好生活的视角成就美好人生人教版高三英语一轮复习练习选修八Unit4(附答案)+高三作文:选好生活的视角成就美好人生

  • 人教版高三英语一轮复习练习选修八Unit2(带答案)+中学生作文:磨不掉的土气人教版高三英语一轮复习练习选修八Unit2(带答案)+中学生作文:磨不掉的土气

  • 外研版高考英语一轮复习必修2 6 Module6知能演练(附答案)+高三作文:免费的春风外研版高考英语一轮复习必修2 6 Module6知能演练(附答案)+高三作文:免费的春风

  • 外研版高考英语一轮复习必修24Module4知能演练(有答案)+中学生作文:不忘坚守担当适应外研版高考英语一轮复习必修24Module4知能演练(有答案)+中学生作文:不忘坚守担当适应

  • 外研版高考英语一轮复习必修31Module1知能演练(有答案)+高三作文:好好活着外研版高考英语一轮复习必修31Module1知能演练(有答案)+高三作文:好好活着

  • 人教版高三英语一轮复习练习选修八Unit3(含答案)+高三作文:也说青春版《红楼梦》人教版高三英语一轮复习练习选修八Unit3(含答案)+高三作文:也说青春版《红楼梦》

  • 人教版高三英语一轮复习练习选修六 Unit 5(带答案)+中学生作文:不忘初心人教版高三英语一轮复习练习选修六 Unit 5(带答案)+中学生作文:不忘初心

  • 外研版高考英语一轮复习必修31Module1知能演练(有答案)+关于网络的作文:言语是无形的杀rhen利器外研版高考英语一轮复习必修31Module1知能演练(有答案)+关于网络的作文:言语是无形的杀rhen利器

  • 人教版高三英语一轮复习练习必修一Unit5(带答案)+关于方寸的作文:微光人教版高三英语一轮复习练习必修一Unit5(带答案)+关于方寸的作文:微光

  • 精品推荐

    相关阅读

    关于我们 - 网站声明 - 网站地图 - 资源地图 - 友情链接 - 网站客服 - 联系我们

    网站客服QQ:2846424093    人人文库上传用户QQ群:460291265   

    [email protected] 2016-2018  renrendoc.com 网站版权所有   

    备案号:苏ICP备12009002号-5