21一种基于线阵相机的激光彩色点云生成方法Word文件下载.docx

21一种基于线阵相机的激光彩色点云生成方法Word文件下载.docx

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（1.ChongqingSurveyInstitute,Chongqing400020,2.BeijingDigsurScience&

TechnologyDevelopmentCo.LTD，BeiJing100012）

ABSTRACT:

Vehicle-bornelaserscanningsystem（VLSS）isequippedwithlaser、linearCCDcameraandGPS/INS/Odometer-basednavigationsystem,whicharealltightlyfixedtoastableelevatingplatforminvehicle.Itisadirectwaywithhighprecisiontoget3Dinformationoftheworld,whichshowsgreatpromisein3Dcityreconstruction.Butdatacapturedbylaserscanneriscolorless,soit’snecessarytoobtaincolorinformationfromothersensor,suchascamera.ThispaperfirstrecallssomeexistingmethodsofcolorfulpointcloudcapturedbyVLSSandthenraisesamethodtoaccomplishthefusionoflaserdataandlinescanningimage,especiallyfocusingonRGBcolor,byparallel-bindinglinearcameraandlaserconsideringconfigurationofourVLSS.Ittakestwostepstoaccomplishthiswork,namelyrigidlyfixinglaserandlinearCCDcameraparallellyandformingacolorlook-uptablebyimage-formingprincipleofsensors.Soitbecomesconvenientandfasttogeneratecolorfulpointcloud,forwhichweconductaserialofexperimentstogetsomedatacapturedinanurbanenvironmentutilizingourVLSSandgiveananalysisoftheresults.Throughthismethod,it’spossibletorealizeautomaticfusionoflaserdata（pointcloud）andlinescanningimagery,avoidingcomplexprogressofcalibrationofcameraandfinallyofferingafastandeffectivewayoftexturematchinginrealistic3Dcityreconstruction.

KeyWords:

Vehicle-bornelaserscanningsystem；

Lasterpointcloud;

3-Dcity

一种基于线阵相机的激光彩色点云生成方法

马红1,郭姣2

（1．重庆市勘测院，重庆400020，2北京帝测科技股份有限公司，北京100012）

摘要：

车载激光扫描系统（VLSS）是多传感器的集成系统，主要由激光扫描仪、线阵CCD相机、和GPS/IMU导航仪固定在稳定的可升降车载平台上。

它可以快速获取高精度三维信息，在三维数字城市建设上有着广泛的应用前景。

激光数据本身没有颜色信息，需要相机同步采集数据，如何实现两种数据的快速融合是一个关键问题。

本文基于激光扫描仪和线阵CCD均以推扫方式获取数据的原理，利用良好设计实现激光和CCD相机的空间同步和时间同步，从而完成点云与RGB颜色值的自动映射。

首先，通过前期检校的手段使两种仪器在机械安装上保证刚性平行，然后同步获取目标数据，并建立点云与影像对应的颜色查找表，从而快速便捷获得目标的彩色点云。

本文通过车载激光扫描系统获取城市环境数据进行了一系列试验和分析，验证了这种方案的可行性。

这种方法避免了复杂的相机检校过程，实现激光点云数据与线阵影像的自动融合，使高效快捷地构建三维数字城市成为可能。

关键词：

车载激光扫描系统；

激光点云；

三维城市

1.Introduction

Recentlytheneedof3DGISdatahasbeenincreasingforvariousapplicationslikenavigation,virtualreality,urbanplanningandmanagement,disastermanagementandentertainment（cinema,computergames）.Vehicle-bornelasersystem（VLSS）isagoodwaywithhighprecisiontoget3Dinformationdirectlythusit’sunderextensivelystudynowadays.ItisequippedwithLiDAR（LightDetectionAndRanging）、linearCCDcameraandGPS/INS/Odometer-basednavigationsystem,whicharealltightlyfixedtoastableelevatingplatforminvehicle.Whiledatacapturedbylaserscanneriscolorlessandnotgoodenoughforobjectinterpretation,it’snecessarytogetcolorinformationfromothersensor,suchascamera.Somanyresearchersareexploringagoodwaytoaccomplishthefusionofpointclouddatawithimagerydata,especiallyfocusingonRGBcolor.Therearetwotypesofcamerawecanconsidertobeoursourceofimage,namelyframecameraandlinearscanningcamera.Ifwechooseframecamera,therewillbealotofworktodoanditwouldbeproblematicinpartbecauseofthecomplexprocessingrequiredandthedifficultiesinaccuratelyassigningacolorfulpixelfromtheimagetothecorrectpointinthecloud.

Let’stakecalibrationforexample,whichisaninevitableprocedure.Thepurposeofcalibrationbasicallyistointegrateallthesensorsandpositioningdevicestoasinglecoordinatesystemsothatwecanintegratedatacapturedbythesensors.Thisalsoincludescomputationofsomeparameterslikefocallengthofthecameralens,imagecenterandlensdistortion.

Invehicle-bornelasersystem,pointsaregeneratedbylasersensorandbecalculatedutilizingthecollinearityequation,whichuses（x,y,z）ofeachpointandnineorientationparametersofthecamera,includingsixexteriororientationparameters（X,Y,Z,Omega,Phi,Kappa）andthreeinnerorientationparameters（,,f）,togetitscorrespondingpointinimageplaneandfinditscolorinformation.Obviouslyit’snecessarytofinishcalibrationofframecameraatfirstandmeasurethepostureofcamerabyGPS/IMUwhilescanning.

Inthisway,itseemscleartoachieveeverypartofwork.Butactuallyeverypartofworkisproblematicandcausedifferenterrors.Firstly,togettheaccuratepointposition（X,Y,Z）,weneedGPS/IMUtoofferaccuratelocationandpostureoflaserscannersothatwecangetabsolutepositionofpointscaptured.ThenthecamerashouldbecalibratedtofindoutitsinnerorientationparametersinacalibrationfieldwhileGPS/IMUshouldofferaccuratepostureofcamera.Obviouslyeverystepisuncertain,leadingtocomplexsystemicerror.Besides,theprocessofcalculationismassive.

Considerin