Image-Based Lighting II15-463: Computational PhotographyAlexei Efros, CMU, Fall 2006…with a lot of slides donated by Paul Debevec© Clément PolineIlluminating a Small SceneIlluminating a Small SceneWe can now illuminatesynthetic objects with real light.How do we add synthetic objects to a real scene?We can now illuminatesynthetic objects with real light.How do we add synthetic objects to a real scene?Real Scene ExampleReal Scene ExampleGoal: place synthetic objects on tableGoal: place synthetic objects on tableLight Probe / Calibration GridLight Probe / Calibration Gridreal scenereal sceneModeling the SceneModeling the Scenelight-based modellight-based modelThe Light-Based Room ModelThe Light-Based Room Modelreal scenereal sceneModeling the SceneModeling the Scenesynthetic objectssynthetic objectslight-based modellight-based modellocal scenelocal sceneThe Lighting ComputationThe Lighting Computationsynthetic objects(known BRDF)synthetic objects(known BRDF)distant scene (light-based, unknown BRDF)distant scene (light-based, unknown BRDF)local scene(estimated BRDF)local scene(estimated BRDF)Rendering into the SceneRendering into the SceneBackground PlateBackground PlateRendering into the SceneRendering into the SceneObjects and Local Scene matched to SceneObjects and Local Scene matched to SceneDifferential RenderingDifferential RenderingLocal scene w/o objects, illuminated by modelLocal scene w/o objects, illuminated by modelDifferential Rendering (2)Difference in local sceneDifferential Rendering (2)Difference in local scene--==Differential RenderingDifferential RenderingFinal ResultFinal ResultIMAGE-BASED LIGHTING IN FIAT LUXPaul Debevec, Tim Hawkins, Westley Sarokin, H. P. Duiker, Christine Cheng, Tal Garfinkel, Jenny HuangSIGGRAPH 99 Electronic TheaterHDR Image SeriesHDR Image Series2 sec2 sec1/4 sec1/4 sec1/30 sec1/30 sec1/250 sec1/250 sec1/2000 sec1/2000 sec1/8000 sec1/8000 secStp1 PanoramaStp1 PanoramaAssembled PanoramaAssembled PanoramaLight Probe ImagesLight Probe ImagesCapturing a Spatially-Varying Lighting EnvironmentCapturing a Spatially-Varying Lighting EnvironmentThe MovieThe MovieSimulating the Glare in the Human EyeSimulating the Glare in the Human Eye• Greg Spencer, Peter Shirley, Kurt Zimmerman, and Donald Greenberg. Physically-based glare effects for digital images. SIGGRAPH 95.• Greg Spencer, Peter Shirley, Kurt Zimmerman, and Donald Greenberg. Physically-based glare effects for digital images. SIGGRAPH 95.Scattering in the eyeWhat’s the scattering model?HDR ImageGaussian Blur, LDR information OnlyGaussian Blur, Full HDR InformationFull HDR Disc BlurFrame Postprocessing in Rendering with Natural LightFrame Postprocessing in Rendering with Natural LightReal objects under new lightingRendering Light Probes as Light Sources19991999A Lighting Reproduction ApproachComposited ResultsEnvironment Map from Single Image?Eye as Light Probe! (Nayar et al)Cornea is an ellipsoidEllipsoid fittingPutting it all together!Reach for the sky• How can we capture the whole sky as an environment map?• What happens with the sun?Direct HDR Capture of the Sun and SkyDirect HDR Capture of the Sun and Sky• Use Sigma 8mm fisheye lens and Canon EOS 1Ds to cover entire sky• Use 3.0 ND filter on lens back to cover full range of light– Only 0.1% of light gets through!• Use Sigma 8mm fisheye lens and Canon EOS 1Ds to cover entire sky• Use 3.0 ND filter on lens back to cover full range of light– Only 0.1% of light gets through!Stumpfel, Jones, Wenger, Tchou, Hawkins, and Debevec. “Direct HDR Capture of the Sun and Sky”. To appear in Afrigraph 2004.Stumpfel, Jones, Wenger, Tchou, Hawkins, and Debevec. “Direct HDR Capture of the Sun and Sky”. To appear in Afrigraph 2004.Extreme HDR Image SeriesExtreme HDR Image Series1 secf/41 secf/41/4 secf/41/4 secf/41/30 secf/41/30 secf/41/8000 sec f/161/8000 sec f/161/30 secf/161/30 secf/161/250 secf/161/250 secf/161/1000 secf/161/1000 secf/161 secf/41 secf/41/4 secf/41/4 secf/41/30 secf/41/30 secf/41/8000 sec f/16only image that does not saturate!1/8000 sec f/16only image that does not saturate!1/30 secf/161/30 secf/161/250 secf/161/250 secf/161/1000 secf/161/1000 secf/16Extreme HDR Image Series- sun closeupExtreme HDR Image Series- sun closeupSpectral Calibration – ND filters are NOT Necessarily Neutral!Spectral Calibration – ND filters are NOT Necessarily Neutral!Before correctionBefore correctionAfter correction based on MacBeth ColorChecker chart appearanceAfter correction based on MacBeth ColorChecker chart appearanceTwo Complete days of HDR Lighting(see video)Two Complete days of HDR Lighting(see video)Feb 22, 2004 Feb 23, 2004(day averages at 1 min. intervals)Lit by sun and skyLit by sun and sky9 samples per pixel, 17 min.9 samples per pixel, 17 min.16 samples per pixel, 46 min.16 samples per pixel, 46 min.100 samples per pixel, 189 min.100 samples per pixel, 189 min.A sunlit sample pointA sunlit sample pointA shadowed sample pointA shadowed sample pointHDRI Sky ProbeHDRI Sky ProbeClipped Sky + Sun SourceClipped Sky + Sun SourceLit by sky only, 17 min.Lit by sky only, 17 min.Lit by sun only, 21 min.Lit by sun only, 21 min.Lit by sun and sky, 25 min.Lit by sun and sky, 25 min.24 Samples per Pixel – 6h, 22min24 Samples per Pixel – 6h,
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