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ID:28362457
大小:10.61 MB
页数:149页
时间:2018-12-09
《螺旋锥束工业ct的katsevich精确重建算法分析》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、重庆大学硕士学位论文用实际扫描的投影数据进行图像重建,然后对重建的图像进行三维边缘提取。本文对螺旋锥束CT的Katsevich重建公式进行了修改,研究了一种利用螺旋锥束CT获得的投影数据直接重建物体三维增强边缘的方法。通过该方法得到的三维增强边缘,可以初步判断物体内部结构的形状及类型,而且三维增强边缘重建时间与螺旋锥束Katsevich算法重建时间相当,节省了三维边缘提取的时间。关挂词:螺旋锥束工业CT,Katsevich精确重建算法,自适应混合滤波,偏移修正,增强边缘重建英文摘要ABSTRACTCT(ComPutedtom
2、ograPhy)15thefruitbytheeomblnationofmathematies,Physies,Photoeleetricity,meehaniesandeomPuterscience,ete.11eanbeclassifiedintotwomajorPractiealfields:MediealCT(MCT)andIndustrialCT(ICT).DuringthePastfortyyears,theseanmodeofICThasbeendeVelopedintothe3DsPiraleone一beam
3、fromtheZDParailel一beam.SPiralcone一beamICTnow15ahotsPotintheresearehingarea.ItPossessesseveralstrongPoints:notonlyithasshorterscantime,higheraxisresolutionandbetterray’5utilization,butalsoitsseanloeussatisfyneeessaryandsuffieientconditionforthe3Dexactreeonstruetion.
4、ThereeonstruetionalgorithmsofsPiraleone一beameanbedividedintotwosorts:algebraiealgorithmsandanalytiealgorithms.Algebraiealgorithmsneediterationmanytimes,50iteostsmuehtime.TherearetwotyPesofanalytiealgorithms:exactandapProximatealgorithms.ComParedwithapProximatealgor
5、ithms,theimagereeonstruetedfromexactalgorithmsriditselfoftheinflueneeofeoneangle,andhavenoshadowintheasPeetoftheory.Also,therearemaiulytwotyPesofex解talgorithms:GrangeatalgorithmandKatseviehalgorithm.DuetohigherefficieneyofthealgorithmimPlementationandbetterqualityo
6、fthereeonstrUetedimage,thesPiraleone一beamKatsevichexactreeonstruetionalgorithmhasattractedinereasingattention.TheexactreeonstruetionrequiresthattheProjeetionsshouldbeeomPleteandwithoutnoise.Unfortunately,insPiraleone一beamICT,theProjeetionsobtainedfromthePractiealen
7、gineeringhavealotofnoise.Thenoise15eausedbymaladjustmentofsomedeteetors,disPersionandcross一talkofX一rays,ete.hiordertomeettheexactreeonstruetioneondition,thenoisedProjeetionsshouldbede一noisedortheexactreeonstrUetionalgorithmsshouldbeimProved.In而5Paper,twostrategiesw
8、ereadoPtedtoredueethenegativeeffeetsresultedfromthenoisewhentheKatsevichalgorithmwasapPliedtoreconstruetthenoisedsPiraleone一beamProjeetions.Thefi
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