简介:Objective:ToevaluateandcomparethediagnosticvalueinatlantoaxialsubluxationbyCTthree-dimensional(3D)reconstruction.Methods:3Dreconstructionfimdingsof41patientswithatlantoaxiaisubluxationwereretrospectivelyanalyzed,andcomparisonsweremadeamongimagesoftransversesection,multiplanarreformorting(MPR),surfaceshadedisplay(SSD),maximumintensityproject(MIP),andvolumerendering(VR).Results:Of41patientswithatlantoaxialsubluxation,31belongedtorotarydislocation,5antedislocation,and5hinddislocation.Allthecasesshowedthedislocatedjointpanelofatlantoaxialarticulation.Fifteencasesshoweddeviationoftheodontoidprocessand8caseswideneddistancebetweenthedensandanteriorarchoftheatlas.ThedislocatedjointpanelofatlantoaxialarticulationwasmoreclearlyseenwithSSD-3Dimagingthananyothermethods.Conclusions:AtlantoaxialsubluxationcanwellbediagnosedbyCT3Dreconstruction,inwhichSSD-3Dimagingisoptimal.
简介:Airborne3DimagewhichintegratesGPS,attitudemeasurementunit(AMU),scanninglaserrangefinder(SLR)andspectralscannerhasbeendevelopedsuccessfully.ThespectralscannerandSLRusethesameopticalsystemwhichensureslaserpointtomatchpixelseamlessly.Thedistinctiveadvantageof3Dimageisthatitcanproducegeo_referencedimagesandDSM(digitalsurfacemodels)imageswithoutanygroundcontrolpoints(GCPs).ItisnolongernecessarytosurveyGCPsandwithsomesoftwaresthedatacanbeprocessedandproducedigitalsurfacemodels(DSM)andgeo_referencedimagesinquasi_real_time,therefore,theefficiencyof3Dimageis10~100timeshigherthanthatoftraditionalapproaches.Theprocessingprocedureinvolvesdecomposingandcheckingtherawdata,processingGPSdata,calculatingthepositionsoflasersamplepoints,producinggeo_referencedimage,producingDSMandmosaicingstrips. Theprincipleof3Dimageisfirstintroducedinthispaper,andthenwefocusonthefastprocessingtechniqueandalgorithm.Theflighttestsandprocessedresultsshowthattheprocessingtechniqueisfeasibleandcanmeettherequirementofquasi_real_timeapplications.
简介:为波浪领域推测的一个精确、宽角度的单程的增殖者面对大、快速的速度变化是为关于波浪方程prestack深度移植的研究的一个重要话题。基于在这篇论文介绍的最佳的可分离的近似,有前面、反的Fourier变换的混合的域算法被用来构造3D单程的波浪领域推测操作员。这个操作员在波浪号码和空间领域分开变量。当为侧面的速度变化的时间延期在空间领域被改正时,阶段移动操作在波浪数字领域被实现。单程的波浪操作符的推动回答证明数字计算与为每速度的理论值一致,表明与最佳的可分离的近似构造的操作符能被用于为小步的盒子的侧面的速度变化。SEG/EAGE模型和领域数据的成像结果显示新方法能习惯于图象建筑群结构。
简介:Inrecentyears,thevolumetricapproachof3Dreconstructionhasemergedasapowerfulclinicmethodforbiomedicalapplications.Thisapproachisbasedonavoxelrepresentedobjectwhichmaintainsmanydetailsofthesurfaceandtheinternalcon-structuresoftheoriginalbody.Becauseofahugeamountofdata,thevolumedatasettakesalargesizeofmemory,andahighprocessingspeedisrequiredinorderto
简介:Severaldifferentstrategiesof3Dmodelingareadoptedfordifferentkindsofmanmadeobjects.Firstly,forthosemanmadeobjectswithregularstructure,if2Dinformationisavailableandelevationinformationcanbeobtainedconveniently,then3Dmodelingofthemcanbeexecuteddirectly.Secondly,forthosemanmadeobjectswithcomplicatedstructurecomparativelyandrelatedstereoimagespaircanbeacquired,inthelightoftopology-based3Dmodelwefinish3Dmodelingofthembyintegratingautomaticandsemi-automaticobjectextraction.Thirdly,forthemostcomplicatedobjectswhosegeometricalinformationcannotbegotfromstereoimagespaircompletely,weturntotopological3DmodelbasedonCAD.