chromatic framework for vision in bad weather srinivasa g. narasimhan and shree k. nayar computer...
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![Page 1: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/1.jpg)
Chromatic Framework for Vision in Bad Weather
Srinivasa G. Narasimhan and Shree K. Nayar
Computer Science Department
Columbia University
IEEE CVPR Conference
June 2000, Hilton Head Island, USA
Sponsors:
ONR MURI , NSF
![Page 2: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/2.jpg)
The Colors of Bad Weather
Clear Day
B
R G
Dense Fog
B
R G
Noon Haze
B
R G
![Page 3: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/3.jpg)
Prior Work
• Overviews : Middleton 1952 , McCartney 1976
• Haze : Hulburt 1946 , Hidy 1972
• Fog : Koshmeider 1924 , George 1951 , Myers 1968
• Vision : Cozman & Krotkov 1997 - Depth Cues from Iso-Intensities
Nayar & Narasimhan 1999 - Complete Structure ; Restricted weather conditions
General Color Framework forAnalysis of Bad Weather Images
OUR GOAL :
![Page 4: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/4.jpg)
Direct Transmission and Airlight Models
Object
Observer
d
( Allard, 1876 )
Direct Transmissiond
E
0E
SunlightDiffuseSkylight
DiffuseGround Light
( Koschmieder, 1924 )
Airlight
EE
d
![Page 5: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/5.jpg)
Dichromatic Atmospheric Scattering Model
B
G
R
Model :
ADE qp 2d
erEp
d
)1( deEq
( Nayar & Narasimhan, 1999 )
EDp Direct Transmission
(True Color )
Aq Airlight (Fog / Haze Color)
![Page 6: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/6.jpg)
Dichromatic Planes
1E
Direct Transmission Color
Airlight Color
A
D
O
Dichromatic Plane
2E
Scene (800 x 600 pixels) Avg. Error (degrees)
Foggy
Hazy
0.25 º
0.31 º
Verification :
![Page 7: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/7.jpg)
Direction of Airlight ( Fog or Haze ) Color
Plane 1 (Scene Point X)
(1)1E
(1)2E
(1)D
O
1N
(2)1E
(2)2E
Plane 2 (Scene Point O)
(2)D
2N
Weather Condition 1
Weather Condition 2
A
Airlight Color from Planes : i
2)(Mini
N A
![Page 8: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/8.jpg)
Depth from Unknown Weather Conditions
Ratio of Direct Transmissions :de
E
E
p
p )(
2
1 21
2
1
Scattering Coefficients : 1 2, ( Unknown )
Sky Brightnesses : 2E, ( Unknown )1E
Depth of a Scene Point :
2
1
2
1
21lnln)(pp
E
Ed
Direct Transmission RatioScaled Depth
Sky Brightness Ratio
![Page 9: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/9.jpg)
Direct Transmission Ratio
Dichromatic Plane
Direct Transmission Color
Airlight Color
A
D
1E 2E
O
C1A
1p
2A
2p
CE
OE
2
1
2
1 p
p
Direct Transmission Ratio :
![Page 10: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/10.jpg)
Sky Brightnesses
Relation Between Sky Brightnesses
12
1
2OC
E
p
pE
Dichromatic Plane
Direct Transmission Color
Airlight Color
A
D
1E 2E
O
C1A
1p
2A
2p
Relative Airlight
Depth of a Scene Point
ln)( 21 d2
1
E
Eln
2
1
pp
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Results with a Synthetic Scene
Color Patches
Recovered Structure
Fog 1 + Noise Fog 2 + Noise
Rotated Structure
![Page 12: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/12.jpg)
Simulation Results
Noise
Estimated
Estimated
Depth Error (%)
0
100
255
0.0
1E
2E
)(
Actual Values = }255,100,5.0{},,{2121 EE
0.5
100.02
255.02
0.42
1.0
100.55
256.61
0.58
1.5
100.65
258.2
0.76
2.0
101.26
260.13
0.82
2.5
103.23
0.89
3.0
104.84
263.45
0.96
255.4
}400,200,67.0{},,{2121 EEActual Values =
Noise
Estimated
Estimated
Depth Error (%)
0
200
400
0.0
1E
2E
)( 0.5
200.02
400.02
0.36
1.0
200.23
400.60
0.53
1.5
200.65
401.1
0.54
2.0
200.96
403.6
0.63
2.5
201.4
0.79
3.0
202.1
405.8
0.93
400.4
![Page 13: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/13.jpg)
Scene under two different Hazy Conditions
Computed Depth Map
Structure from Two Weather Conditions
![Page 14: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/14.jpg)
Structure from Two Weather Conditions
Scene under two different Foggy Conditions
Computed Depth Map
![Page 15: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/15.jpg)
True Color Recovery - Color Cube Boundary Algorithm
RG
B
1
2
3
O
d
d
)(
~
12
Min
Minimum Time to Collision
First Collision with Color Boundary
![Page 16: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/16.jpg)
True Color Recovery
Scene under two different Foggy Conditions
Computed True Color
( Brightened )
![Page 17: Chromatic Framework for Vision in Bad Weather Srinivasa G. Narasimhan and Shree K. Nayar Computer Science Department Columbia University IEEE CVPR Conference](https://reader035.vdocument.in/reader035/viewer/2022062714/56649d5f5503460f94a3fb5e/html5/thumbnails/17.jpg)
Summary
• Scene Depth from Dichromatic Constraints
• Airlight Color from Dichromatic Planes
• True Color from Color Boundary Constraint
Color Framework for Vision in Bad Weather