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1、上海交通大學(xué)碩士學(xué)位論文基于圖像的真實(shí)感繪制技術(shù)研究姓名:金國申請學(xué)位級別:碩士專業(yè):計(jì)算機(jī)軟件與理論指導(dǎo)教師:楊旭波;肖雙九20090101真實(shí)感圖像繪制技術(shù)研究摘要1.提出了結(jié)合漫反射紋理的BRDF技術(shù),大大增強(qiáng)了物體表面紋理細(xì)節(jié)效果,解決了傳統(tǒng)的BRDF只能反映物體表面光學(xué)特性的缺點(diǎn)。2.使用基于拋物面紋理映射的方法,來存儲BRDF分解壓縮后的數(shù)據(jù)。使用這種與視點(diǎn)無關(guān)的環(huán)境紋理貼圖不會產(chǎn)生奇異點(diǎn),能更好的在任意兩個反射方向之間進(jìn)行插值。3.使用MIPMAP技術(shù),大大改善了因?yàn)樵诩y理插值時形
2、成的走樣問題。4.結(jié)合LOD技術(shù),大大增強(qiáng)了BRDF技術(shù)在大場景中應(yīng)用的可能性。5.提出了基于點(diǎn)的方法來近似模擬BTF的技術(shù),在僅用少量紋理圖片的情況下就能很好的保留物體表面材質(zhì)的紋理細(xì)節(jié),如自陰影等效果。大大的提升了渲染速度。本文的方法可以廣泛的應(yīng)用于電影、動畫、游戲、虛擬現(xiàn)實(shí)等領(lǐng)域。關(guān)鍵詞:基于圖像的重光照,雙向反射分布函數(shù)(BRDF),雙向紋理函數(shù)(BTF),3維紋理第II頁真實(shí)感圖像繪制技術(shù)研究ABSTRACTImage-basedphotorealisticrenderingtechn
3、ologyresearchABSTRACTPhotorealisticrenderingtechnologyofcomputergraphicsisanimportantissue.Realisticlighteffectismainobjectiveofphotorealisticrenderingtechnologyandthematerialattributeisthekeyproblem.Atpresent,themethodwhichcanwellsimulatetheillumina
4、tionpropertiesofthematerialsisbasedonphotos.Themainresearchcandivideintothreecatalogues:Reversedrawing,Image-basedrelighting,Lightsamplingbasedonmaterialsamples.Reversedrawingcancomputethematerialparametersoftheobject,buthardtoachievingrealtimerender
5、ingoftheglobalillumination.Italsorequiresstrictlightcondition.Image-basedrelightingrequiresmanysamples,andhardtorebuildthehigh-frequencycomponentsofthelightonthesurface.Lightsamplingbasedonmaterialsamplesacquiresmanysamplesunderdifferentlightposition
6、andviewposition.Thismethodcandividesintotwomainmethods:BRDFandBTF.Allthesetwomethodsneedhugedata,andrequireefficientcompressionmethod.ThisthesisfocusonLightsamplingbasedonmaterialsamples,anddomanyresearchesincludeBRDF,TextureMapping,andtheapproximate
7、BTF.第I頁真實(shí)感圖像繪制技術(shù)研究ABSTRACTFollowingwilllistthemainresults:1.CombinediffusemapandBRDFtechnology.Enhancetexturedetailofthesurface.2.Useparabolictexturemappingtechnologytosavethecompresseddatafromrawimages.Usethistechnologywhichisnotrelevanttoviewpositi
8、onwillnotproducesingularitypointsandcanmakemoreeffectivetointerpolatingbetweenanyreflectorientations.3.UseMIPMAPtechnologywhichimprovedaliasingproblemcausedbytextureinterpolation.4.CombinewithLODtechnology,makeitcanuseincomplexscene.5.Advancedamethod