1 diffusion coded photography for extended depth of field siggraph 2010 oliver cossairt, changyin...
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1
Diffusion Coded Photography
for Extended Depth of Field
SIGGRAPH 2010Oliver Cossairt, Changyin Zhou, Shree Nayar
Columbia University
Supported by ONR and NSF
2
Conventional Camera (F/1.8)
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Conventional Camera (F/18)
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Focused ImagePSF
Image Noise Captured Image
Camera Blur ModelS
pati
al d
om
ain
Focused Image MTF Image Noise Captured ImageFreq
uen
cy d
om
ain
(Modulated Transfer Function)
5
Deblurring Problems
MTFCaptured image
Low SNR
Low MTF values
Problem 1:
Focused image
Lens
Sensor
P
Object
Q
Problem 2:
Variation with depth
6
Extending Depth of Field (EDOF): Previous Work
Focal Sweep Cameras[Hausler ’72]
[Nagahara et al. ’08]Lens Focal PlaneSensor
Other Related Work[Levin et al. ’07][Veeraraghavan et al. ’07] [Levin et al. ’09]
Wavefront Coding Cameras
[Dowski and Cathey ’95] [Chi and George ’01] [Garcia-Guerrero et al. ‘07] LensSensor
Cubic Phase Plate
7
Focal sweep vs. wavefront coding
Focal Sweep
WavefrontCoding
ConventionalCamera
near farfocus
depth
Note: only a single PSF will be used to deblur the whole image.
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Deblurring Error vs. DepthD
eblu
rrin
g E
rror
noise
DepthWavefront
CodingFocal Sweep
2
0FFE dd
Focal sweep vs. wavefront coding
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Achieve the performance of focal sweep without any moving parts?
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Optical Diffusers
Diffuser
[http://www.luminitco.com]
Diffuser sheets
w
SensorDiffuser
Light ray
x
x
Scatter function
w
SEM image
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Diffuser Kernels
xu A/2
-A/2
u
x
Light FieldWithout a diffuser:
Lens
A
Sensor
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Diffuser Kernels
A/2
-A/2
u
x
Light FieldWithout a diffuser:
With a diffuser:
A/2
-A/2
u
x
xu
Lens Sensor
xu
Lens Sensor
A
A
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Diffuser Kernels
A/2
-A/2
u
x
Light FieldWithout a diffuser:
With a diffuser:
u
x
A/2
-A/2
xu
Lens Sensor
xu
Lens Sensor
A
A
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Diffusion Kernels
A/2
-A/2
u
x
Without diffuser
u
x
With diffuser
u
x
Diffuser kernel
Lig
ht
field
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A/2
-A/2
u
x
u
x
u
x
Lig
ht
field
Diffusion Kernels
x
project
x
project
x
project
PS
F
Diffused PSFScatter functionCamera PSF
Without diffuser With diffuserDiffuser kernel
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Radially Symmetric Diffuser
LensSensor
PSFWithout a diffuser:
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Without a diffuser:
LensSensor
With a diffuser:
LensSensor
PSF
Radially Symmetric Diffuser
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LensSensor
With a diffuser:
LensSensor
PSFWithout a diffuser:
Radially Symmetric Diffuser
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LensSensor
LensSensor
PSF
With a diffuser:
Without a diffuser:
Radially Symmetric Diffuser
20Lens
Sensor
With a diffuser:
Radially Symmetric Diffuser
LensSensor
PSFWithout a diffuser:
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LensSensor
LensSensor
PSF
With a diffuser:
Without a diffuser:
Radially Symmetric Diffuser
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LensSensor
LensSensor
PSF
With a diffuser:
Without a diffuser:
Radially Symmetric Diffuser
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Radially Symmetric Diffuser
PSF:
Scatter function
CameraPSF
PSF(1D slice)
MTF(1D slice)
Normalized frequency Normalized frequency Normalized frequency Normalized frequency
K7
K9
K11
K13
k7
k9
k11
k13
-50px 50px -50px 50px -50px 50px -50px 50px
depth
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Diffusion Coding PerformanceDeblurring Error vs. Depth
Depth
Wavefront CodingFocus Sweep
noise
Diffusion Coding (light field)Diffusion Coding (wave optics)
Similar performance to focal sweep without moving parts
Deb
lurr
ing
Err
or
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Diffuser ImplementationDiffuser scatter function
)(rf
r (mm)
[www.rpcphotonics.com]
Diffuser height map Fabricated diffuser
110
Thic
kn
ess
(u
m)
3
863
2
1
)(rt
r (mm)
Diffuser surface profile
RPC Photonics
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Garcia-Guerrero
Comparison with Prior Work
Deblurring Error vs. Depth
Depth
Diffusion Coding
Diffusion coding significantly outperforms prior work.
Deblu
rrin
g E
rror
x 16
1
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Diffusion Coding Experiments
Fabricated DiffuserCannon 50mm EF lensCannon 450D Sensor
Experimental Setup
Measured PSFs
depth
Without diffuser
With diffuser
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Examples
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Stuffed Toys
f-number = 1.8, exposure time = 16ms
Conventional Camera
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Stuffed Toys
f-number = 18 , exposure time = 16ms
Conventional Camera
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Stuffed Toys
Diffusion Coding Camera: Captured
f-number = 1.8, exposure time = 16ms
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Stuffed Toys
f-number = 1.8, exposure time = 16ms
Diffusion Coding Camera: Deblurred
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Statues
f-number = 1.8; exposure time = 10ms
Captured Deblurred
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People and Flowers
f-number = 1.8, exposure time = 16ms
Conventional Camera
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People and Flowers
f-number = 1.8, exposure time = 16ms
Diffusion Coding Camera: Captured
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People and Flowers
f-number = 1.8, exposure time = 16ms
Diffusion Coding Camera: Deblurred
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LimitationsConventional Camera Diffusion Coding
• Loss of image texture
• Loss of contrast
• Occlusion errors
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Conclusions
Diffusion Coding Theory
Diffusion Coding Implementation)(rf
Diffusion Coding Examples
Radially Symmetric Diffusers
39
Diffusion Coded Photography
for Extended Depth of Field
SIGGRAPH 2010Oliver Cossairt, Changyin Zhou, Shree Nayar
Columbia University
Supported by ONR and NSF