Photorealistic Rendering of Rain Streaks
32
Photorealistic Rendering of Rain Streaks Department of Computer Science Columbia University Kshitiz Garg Shree K. Nayar SIGGRAPH Conference July 2006, Boston, USA Sponsors: NSF, ONR
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Photorealistic Rendering of Rain Streaks. Kshitiz Garg Shree K. Nayar. Department of Computer Science Columbia University. SIGGRAPH Conference July 2006, Boston, USA Sponsors: NSF, ONR. A Rain Scene from “The Matrix Revolutions”. A Rain Scene from “The Matrix Revolutions”. - PowerPoint PPT Presentation
Transcript of Photorealistic Rendering of Rain Streaks
Photorealistic Rendering of Rain Streaks
Department of Computer Science
Columbia University
Kshitiz Garg Shree K. Nayar
SIGGRAPH ConferenceJuly 2006, Boston, USA
Sponsors: NSF, ONR
A Rain Scene from “The Matrix Revolutions”
A Rain Scene from “The Matrix Revolutions”
Frame 1 Frame 2 Frame 3
Rendering Streaks using Simple Brightness Model
Commercial Software Heuristic-based
Hybrid-Spectral Method ATI ToyShop Demo
[Starik and Werman 03]
[Langer et al. 04] [N. Tataturschuk et al. 05]
Original Image Courtesy Andy Lomas Hand Drawn Textures
Original Image Courtesy Warner Bros.Frame from “The Matrix Revolutions”
Rendering Streaks using Hand Drawn Textures
Study of Visual Appearance of Rain Streaks
• Rain Streak Appearance Model
• Rain Streak Texture Database
• Image-Based Rain Rendering Algorithm
Oscillations in a Rain Drop
A Falling Rain Drop
[Beard and Kubesh 1989Andsager et al. 1992]
Turbulent Flow of air
Turbulent Flow of air
Oscillations in a Rain Drop
Oblate-Prolate Mode Transverse Mode
Oscillations in a Rain Drop
[Beard and Kubesh 1989Andsager et al. 1992]
Appearance of a Rain Drop
Refraction
n̂
)ˆ(nL
)ˆ(sLe
)ˆ( pLe
Internal Reflection
S
P
)ˆ(nL )ˆ( pLP e)ˆ(sLS e)ˆ(rLR e
Specular Reflection
R
)ˆ(rLe
N
Appearance of a Non-Oscillating Rain Drop
n̂
)ˆ(nL N
P
R
S
Rain Streak
Instant Time Shots
FallingDrop
Non-Oscillating Rain Drop
)ˆ(nL
n̂
N
P
R
S
Rain Streak
Instant Time Shots
FallingDrop
P
R
S
Appearance of an Oscillating Rain Drop
Oscillating Rain Drop
Rain Streak Appearance Model
Oblate-ProlateMode
Transverse Mode
1,3A0,2A? ?
Shape of Rain Drop:
Fall Direction
Not Rotationally Symmetric
[Beard and Kubesh 1989Andsager et al. 1992]
drop = (00 – 3600)
Measurement of Rain Streak Appearances
Drop generator
Height: 15 m
-z
x
xdrop
y,ydrop
droplight
viewlight
light = (500, 900, 1300)
light = (100 , 300,…, 1700)
view = (700, 900, 1100)
(A2,0 A3,1 drop) =(10 images per light & view)
Lighting and Viewing Configuration
Experimental Setup
Oscillation Parameters
Estimation Result
1,3A0,2A
;)1.0,2.0(),( 1,30,2 AA )1.0,1.0(
90 70
130 50 130 90 50 130 90 50
light
view
light
110
90
130 10 70 30 10 150 30 10 110 50 170 30 170 90 110 50 130 30
Estimating the Oscillation Amplitudes
Measu
red
Oscillation Amplitudes:
Comparison of Actual vs. Rendered Rain Streaks
90 70
130 50 130 90 50 130 90 50
light
view
light
110
90
130 10 70 30 10 150 30 10 110 50 170 30 170 90 110 50 130 30
Ren
dere
dM
easu
red
Precomputed Database of Streak Textures
Lighting and Viewing Direction
Oscillations Parameters
Database contains 6300 HDR Rain Streak Textures (400 MB)
Rain Drop Size
Source and Camera Distance
Camera Parameter
Factors Affecting the Appearance
( Publicly available: Please send email to [email protected] )
Render Online (Algorithm)
Render Offline (Database)
User Input
Scene Image/Video
Camera and Rain
Parameters
Coarse Depth Map
Light SourceProperties
Scene Image/Video
With Rain
Raindrop Distribution
and Trajectories
Using Particle System
Render Streak Appearance
Scale
Rotate
PerspectiveEffects
CameraEffects
ExposureCrop/Blend
DefocusBlur
Rain Dynamics
Rain Rendering PipelineRender Novel
Streak Textures
Rain Streak Database
Streak texture(Source 1)
Streak texture(Source n)
+
+Streak texture
(Ambient)
Rendered Rain with Varying Light Direction
-150o150o
Light Source Direction
Constant Brightness Streak Model
-150o 150o
Light Source Direction
Comparison with Constant Brightness Model
Streak Appearance Model Constant Brightness Model
Night Scene with Isotropic Source
Coarse Depth Map
Image of the Scene
Night Scene with Isotropic Source
Rendered Rain
Night Scene with Isotropic Source
Defocus Effects
Scene with Multiple Sources
Scene with Colored and Anisotropic Sources
Coarse Depth Map
Scene with Colored and Anisotropic Sources
Rendered Rain
Scene with Colored and Anisotropic Sources
Streak Appearance ModelConstant Brightness Model
Scene with Changing Sky Illumination
Input Scene Video
Scene with Changing Sky Illumination
Rendered Rain
A Scene with Moving Light Sources
Input Scene Video
Rendered Video
A Scene with Moving Light Sources
Future Extensions
• Real-time Implementation of Rendering Algorithm
• Incorporating the Effects of Wind and Turbulence
Ren
der
edR
ain
Stre
aks
Rea
l Im
ages
of
Rai
n St
reak
s
Lighting Angle
Viewing Angle
Ren
der
edR
ain
Stre
aks
Rea
l Im
ages
of
Rai
n St
reak
s
Lighting Angle
Viewing Angle
Summary
Image-Based Rain Rendering Algorithm
Rain Streak Texture Database ( Publicly available: [email protected] )
Rain Streak Appearance Model
1,3A0,2A
