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07. E U R O G R A P H I C S. Depth - of -Field Rendering by Pyramidal Image Processing. Martin Kraus (TU München) and Magnus Strengert (Universität Stuttgart). 00. Outline of this Talk. 01 Introduction 02 Related work 03 Proposed method 04 Experiments 05 Future work. 01.
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07 E U R O G R A P H I C S Depth-of-Field Renderingby Pyramidal Image Processing Martin Kraus (TU München) and Magnus Strengert (Universität Stuttgart)
00 Outline ofthis Talk 01Introduction 02Relatedwork 03Proposedmethod 04 Experiments 05 Future work
01 I N T R O D U C T I O N What Is Depthof Field? • The depth in front andbeyondthefocus plane whereobjectsappeartobe in focus • A propertyof all realopticalsystems • onlyvirtualpin-hole camerashave infinite depthoffield • Usedforimportantphotographicandcinematographictechniques
photoby Jon Sullivan (http://pdphoto.org/PictureDetail.php?mat=pdef&pg=8202)
photoby "che" (http://commons.wikimedia.org/wiki/Image:Dandelion_clock_detail.jpg)
02 R E L A T E D W O R K ClassificationofTechniques: • Splatting [Potmesil & Chakravarty 1982] • Stochasticsampling [Cook et al. 1984] • e.g., in distributedraytracingor in REYES • stateoftheart in offline rendering • Pre-filtering [Rokita 1993] • lots ofartifacts [Demers 2004] • stateoftheart in real-time rendering • Blurringof sub-images [Barsky 2004]
02 R E L A T E D W O R K High Quality in Real Time? • Real-time performancerequires: • independenceofscenecomplexity • excludesstochasticsampling • thus: image post-processingof a pin-hole colorimageanddepthmap • independenceofimagesynthesisforfree • convolutionfilteringistoo expensive • evenwith FFTs on GPUs • thus: blurringusingpyramidalgorithms
02 R E L A T E D W O R K High Quality in Real Time? • High imagequalityrequires: • smooth blurringwithoutinterpolationartifacts • pyramidblurring [Kraus & Strengert 2007] • noincorrectcolorbleeding • excludespre-filtering • separate blurringof sub-images • disocclusionof semi-transparent pixels • inpaintingofcolorsanddepthswithpyramidalgorithm [Strengert et al. 2006]
03 P R O P O S E D M E T H O D Overview pin-hole image & depthmap decompositioninto sub-images 3 1 4 disocclusion matting blurring 2 blendingof sub-images 5 resultingimage
03 P R O P O S E D M E T H O D Decomposition • decomposeinto sub-imagesandcullforegroundpixelsaccordingtodepthmap 1
03 P R O P O S E D M E T H O D Disocclusion • foreach sub-image: disoccludeculledforeground (using pyramidal inpainting) 2
03 P R O P O S E D M E T H O D Matting • foreach sub-image: computealpha-mattingaccordingtoeachpixel'sdepth 3
03 P R O P O S E D M E T H O D Blurring • foreach sub-image: blurcolorandalpha (using pyramidal blurring) 4
03 P R O P O S E D M E T H O D Blending • back-to-front blendingof all sub-images • resultcomputed in 70.4 ms • (12 sub-images,hardware: • NVIDIA GeForce 7900 GTX) 5
03 P R O P O S E D M E T H O D Main Features • independentofscenecomplexity • andindependentofimagesynthesis • interactiveperfomance on GPUs • real-time forsmallcirclesofconfusion • highimagequality • avoidsartifactsofpre-filteringtechniques • let's do someexperiments …
04 E X P E R I M E N T S OurMethod vs. pbrt • pbrtusesstochasticsampling • Whichiswhich?
04 E X P E R I M E N T S OurMethod vs. pbrt pbrt our method
04 E X P E R I M E N T S OurMethod vs. pbrt • Whichiswhich?
04 E X P E R I M E N T S OurMethod vs. pbrt pbrt our method
04 E X P E R I M E N T S Can We Break OurMethod? • Yes, with a very largelensradius. pbrt bleeding gray too opaque our method
04 E X P E R I M E N T S Can We Break OurMethod? • Video withvery large lensradii:eg07.mov • also availableat: http://wwwcg.in.tum.de/Research/Publications/DepthOfField
05 F U T U R E W O R K Are Wethereyet? • No, but weavoidtypicalrenderingartifactsof real-time techniques • Specializedvariantsforbetterperformanceandimagequality • Alternative blurfilters • High-potential application: • gaze-directedfocus
06 A C K N O W L E D G M E N T S • The photosappearcourtesyof "che" and Jon Sullivan. • The dragon model appearscourtesyofthe Stanford University Scanning Repository. • The pbrtsceneappearscourtesyof Gregory Humphreys and Matt Pharr.
07 E U R O G R A P H I C S Thankyou! Andhave a safetriphome! Questions?
07 E U R O G R A P H I C S