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ID:55731427
大小:1.43 MB
页数:7页
时间:2020-06-01
《非线性自适应迭代重建算法用于相干层析抗噪仿真.pdf》由会员上传分享,免费在线阅读,更多相关内容在应用文档-天天文库。
1、光电子·澈光第24卷第8期2013年8月JournalofOptoelectronics·LaserVo1.24No.8August2013非线性自适应迭代重建算法用于相干层析抗噪仿真曲培树,宋一中(德州学院物理系,山东德州253000)摘要:为进一步完善非线性自适应迭代重建算法(NAIRT)并将其可靠地应用于实际流场层析诊断,仿真研究了NAIRT的抗噪性能。采用仿真技术,模拟含跳变的复杂空气流场,相干投影,获得Radon变换投影数据。采用RandG函数模拟产生Gauss随机噪声,噪声的相对强度通过信噪比(sNR)标征,设置强度不同的SNR,获得相应的随机噪声。随机噪声与投影数据线性叠加,获得
2、含噪投影。采用NAIRT逆投影重建,重建结果与无噪重建结果比较,并用均方差(MsE)对重建结果定量分析。结果发现,在60dBSNR噪声情况下,NAIRT能够比较精确重建仿真流场,MsE降到1.82×10;10dBSNR时,NAIRT仍能重建出仿真场的轮廓,MSE稳定在4.91×1O;100dBSNR时,NAIRT能够十分精确地重建仿真流场,MSE衰减到1.26×106,逼近无噪重建效果。重建图像和误差分析都表明,NAIRT具有十分优越的抗噪性能。关键词:非线性自适应迭代重建算法(NAIRT);抗噪性能;随机噪声;信噪比(SNR);投影;重建中图分类号:0438文献标识码:A文章编号:1005—
3、0086(2013)08—1644—07SimulationOilanti-noiseperformanceofnonlinearauto-adjustingiterativereconstructiontechniqueusedininterferometrictomo。·graphyQuPei-shu,SONGYi-zhong(DepartmentofPhysics,DezhouUniversity,Dezhou253000,China)Abstract:Inordertofurtherimprovenonlinearauto-adjustingiterativereconstructio
4、ntechnique(NAIRT)andreliablyapplyittodiagnoseactualairflowfield,theanti-noiseperformanceoftheNAIRTisspeciallyinvestigatedbysimulations.Acomplicatedairflowfieldissimulatedwithtransitionobject.Itisprojectedbyinterferometrictomography.TherealprojectionsareobtainedbyRadontransformation.Gaussianrandomnoi
5、sesignalsaresimulatedtobeproducedwithfunctionRandG.ThenoiseSrelativeintensityisexpressedwiththeratioofsignaltonoise(s/N).AseriesofcorrespondingGaussianrandomnoisesignalsareproducedwithdifierentintensitylevelsbysimplecalculation.Theprojectionscontainingnoisesareobtainedfromtherealprojectionsaddedwith
6、noise1inearly.Theinverseprojectionreconstruc—tionsareimplementedwithNAIRT.Thereconstructedresultsareanalyzedinmeansquareerror(MSE)indexandcomparedwiththeresultreconstructedwithcleanprojectionsunderthesameconditions.Atthenoiselevelof6OdBS/N,NAIRTcouldreconstructthemodelbyadecentaccuracy.TheMSEdec—lin
7、stO1.82×10—5afterabout40iterationcycles.Atthenoiseleve1of10dBS/N,NAIRTcouldstil1reconstructthemodelbytheleveloftheprofile.TheMSEiSstabilizedat4.91×10afterabout40it—erationcycles.Atthenoise1eve1of100dB
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