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Diffusion Coding Photography for Extended Depth of Field SIGGRAPH 2010 Ollie Cossairt, Changyin Zhou, Shree Nayar Columbia University. Conventional Camera (F/1.8). Frequency domain. Image Noise. Focused Image. MTF. Captured Image. Camera Blur Model. Spatial domain. Focused Image.
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Diffusion Coding Photography for Extended Depth of FieldSIGGRAPH 2010Ollie Cossairt, Changyin Zhou, Shree NayarColumbia University
Frequency domain Image Noise Focused Image MTF Captured Image Camera Blur Model Spatial domain Focused Image Captured Image PSF Image Noise
Deblurring Problems Low SNR Focused image Problem 2: Sensor Object P Q Lens Problem 1: low MTF values Captured image MTF Variation with depth
Extending Depth of Field: Previous Work Focus Sweep Cameras [Hausler ’72] [Nagahara et al. ’08] Wavefront Coding Cameras [Dowski and Cathey ’95] [Chi and George ’01] [Garcia-Guerrero et al. ‘07] Other Related Work [Levin et al. ’07] [Veeraraghavan et al. ’07] [Levin et al. ’09] Sensor Lens Focal Plane
Instantaneous PSF + + + + + + t = 1 Focus Sweep Camera Scene [Hausler ’72] [Nagahara et al. ’08] Sensor Lens Final PSF = t = 2 t = 3 t = 4 t = 5 t = 6 t = 7
+ + + + + + + + + Final PSF + + + = t = 2 t = 3 t = 4 t = 5 t = 6 t = 7 2D MTF [Levin et al. ’09] Focus Sweep Camera Scene [Hausler ’72] [Nagahara et al. ’08] Sensor Lens Final PSF Instantaneous PSF = depth 1 t = 1 t = 2 t = 3 t = 4 t = 5 t = 6 t = 7 Instantaneous PSF depth 2 t = 1
2D MTF Ambiguity Function MTF slice [Levin et al. ’09] Wavefront Coding x u Lens Scene Sensor Cubic Phase Plate [Dowski and Cathey ’95]
Focus Sweep Wavefront Coding depth EDOF Camera Comparison Sensor Lens Resolution Target
EDOF Camera Comparison Deblurred image Focus Sweep Wavefront Coding
Deblurring Error vs. Depth Wavefront Coding Focus Sweep Deblurring Error Focus Sweep Wavefront Coding noise Deblurring Error Deblurring Error Depth
Is it possible to achieve the performance of focus sweep without moving parts?
x Scatter function Light ray w x w Diffuser Sensor Optical Diffusers Circular diffuser SEM image Diffuser sheets [http://www.luminitco.com]
A Without diffuser With diffuser u u A/2 A/2 Light field space x x -A/2 -A/2 Diffuser Kernels u x Sensor Lens
w u A/2 Light field space x -A/2 w w w Diffuser Kernels u x Sensor Lens Without diffuser With diffuser u x
w Diffuser kernel u A/2 Light field space x -A/2 Light field Diffuser kernel Coded light field Diffuser Kernels u x Sensor Lens Without diffuser With diffuser u u x x
A/2 project project project Sensor space -A/2 x x x Camera PSF Scatter function Coded PSF Diffusion Coded PSF Without diffuser Diffuser kernel With diffuser u u u Light field space x x x
Lens Sensor v u Radially Symmetric Light Field For an on-axis, isotropic point source:
Lens Sensor Sensor Radially Symmetric Diffuser For a radially-symmetric diffuser kernel
Radially Symmetric Diffuser PSFs Radially symmetric diffuser Coded PSF Scatter function Camera PSF PSF Vs. Depth -50px 50px -50px 50px -50px 50px -50px 50px depth MTF Vs. Depth Normalized frequency Normalized frequency Normalized frequency Normalized frequency depth Conventional diffuser Coded PSF Scatter function Camera PSF
Diffusion Coding Performance Diffusion Coding (light field) Diffusion Coding (wave optics) Deblurring Error vs. Depth Wavefront Coding Focus Sweep noise Depth Similar performance to focus sweep without moving parts
Diffuser Implementation Diffuser scatter function r(mm) Diffuser heightmap Fabricated Diffuser Diffuser surface profile 3 2 Thickness (um) [Sales et al. ‘03] [www.rpcphotonics.com] 1 6 0 3 8 11 r(mm)
Comparison with Prior Work Deblurring Error vs. Depth Diffusion Coding Garcia-Guerrero Depth Diffusion coding significantly outperforms prior work
Measured PSFs Without diffuser with diffuser depth Diffusion Coding Experiments Experimental Setup Fabricated Diffuser Cannon 50mm EF lens Cannon 450D Sensor BM3D Deblurring Algorithm [Dabov et al. ‘08]
Conventional Camera f-number = 1.8, exposure time = 16ms
Conventional Camera f-number = 18 , exposure time = 16ms
Diffusion Coding Captured f-number = 1.8, exposure time = 16ms
Diffusion Coding Deblurred f-number = 1.8, exposure time = 16ms
Conventional Camera • f-number = 1.8 • exposure time = 10ms
Diffusion Coding Captured • f-number = 1.8 • exposure time = 10ms
Diffusion Coding Deblurred • f-number = 1.8 • exposure time = 10ms
Conventional Camera • f-number = 1.8 • exposure time = 12.5ms
Diffusion Coding Captured • f-number = 1.8 • exposure time = 12.5ms
Diffusion Coding Deblurred • f-number = 1.8 • exposure time = 12.5ms
Conventional Camera f-number = 1.8, exposure time = 16ms
Diffusion Coding Captured f-number = 1.8, exposure time = 16ms
Diffusion Coding Deblurred f-number = 1.8, exposure time = 16ms
Loss of contrast • Occlusion errors Limitations Conventional Camera Diffusion Coding • Loss of image texture
Radially Symmetric Diffusers Diffusion Coding Examples Diffusion Coding Implementation Conclusions Diffusion Coding Theory Diffuser Sensor Lens