data-driven local coordinate systems for image-based rendering

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1、EUROGRAPHICS2006/E.GröllerandL.Szirmay-KalosVolume25(2006),Number3(GuestEditors)Data-drivenLocalCoordinateSystemsforImage-BasedRenderingGeroMüller†,RalfSarlette‡andReinhardKlein§InstituteforComputerScienceII,UniversityofBonnAbstractImage-basedrepresentat

2、ionsofanobjectprofitfromknowngeometry.Themoreaccuratethisgeometryisknown,thebettercorrespondingpixelsinthedifferentimagescanbealigned,whichleadstolessartifactsandbettercompressionperformance.Foropaqueobjectstheper-pixeldatacanthenbeinterpretedasasamplingo

3、ftheBRDFattherespectivesurfacepoint.Inordertoparameterizethissampleddataacoordinateframehastobedefined.Inpreviousworkthiscoordinateframewaseithertheglobalframeoralocalframederivedfromthebasegeometry.Bothapproachesleadtomisalignmentsbetweensamplevectors:Fe

4、aturesofbasicallyverysimilarBRDFswillbeshiftedtodifferentregionsinthesamplevectorleadingtopoorcompressionperformance.InordertoimprovealignmentbetweenthesampledBRDFsinimage-basedrendering,weproposeanoptimizationalgorithmwhichdeterminesconsistentcoordinate

5、framesforeverysamplepointontheobjectsurface.Thiswayweefficientlyalignthefeaturesevenofanisotropicreflectionfunctionsandreconstructapproximatelocalcoordinateframeswithoutperforminganexplicit3D-reconstruction.Theoptimizationiscalculatedefficientlybyexploiting

6、theFourier-shifttheoremforsphericalharmonics.Inordertodealwithdifferentmaterialsinascene,thetechniqueiscombinedwithaclusteringalgorithm.WedemonstratetheutilityofourmethodbyapplyingittoBTFsand6Dsurfacereflectancefields.CategoriesandSubjectDescriptors(accord

7、ingtoACMCCS):I.3.3[Picture/ImageGeneration]:DigitizingandscanningI.3.7[Three-DimensionalGraphicsandRealism]:Color,shading,shadowing,andtexture1.Introductiontions[DHT∗00]insteadofmodelingtheappearancewhichcanbeacomplexandsometimesevenimpossibletask.Duetot

8、headventofsophisticatedacquisitiondevicesandcompressionalgorithmsdata-driventechniquesbecamein-AkeyissueinIBRistheparametrizationoftheplenopticcreasinglypopularinthecomputergraphicscommunitydur-function,i.e.,theparametriza