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Diffusion Diffusion Filters Filters S. Derin Babacan S. Derin Babacan Department of Electrical and Computer Department of Electrical and Computer Engineering Engineering Northwestern University Northwestern University March March 7 7 , 200 , 200 6 6 ECE 463 Term Project

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Page 1: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Diffusion FiltersDiffusion Filters

S Derin BabacanS Derin BabacanDepartment of Electrical and Computer Department of Electrical and Computer

EngineeringEngineeringNorthwestern UniversityNorthwestern University

MarchMarch 77 200 20066

ECE 463 Term Project

IntroductionIntroduction

Filters for enhancement restoration Filters for enhancement restoration smoothing and feature extractionsmoothing and feature extraction

Varying for each data entry based on Varying for each data entry based on local featureslocal features u u = [u(0)u(1)u(n-1)u(n)]= [u(0)u(1)u(n-1)u(n)] ww = [ = [ww0 0 w w1 1 w wn-1 n-1 w wn n ]]

wwi i = [w= [wii(0) w(0) wii(1) w(1) wii(m-1) w(m-1) wii(m) ] (m) ]

Mean-value preservingMean-value preserving

Physics of DiffusionPhysics of Diffusion

Fickrsquos LawFickrsquos Law Continuity Continuity

Diffusion EquationDiffusion Equation

Gradient (uGradient (uxx u uyy) )

Divergence div Divergence div ΨΨ = = ΨΨ xx + + ΨΨ yy

Concentration replaced by data valuesConcentration replaced by data values

FluxDiffusion Tensor

Gradient

Concentration

Diffusion FiltersDiffusion Filters

D a scalar (flux and gradient are parallel)D a scalar (flux and gradient are parallel) Isotropic diffusion Isotropic diffusion D spatially invariant (fixed) Homogeneous D spatially invariant (fixed) Homogeneous

linear linear D = g(D = g() Inhomogeneous (linearnonlinear)) Inhomogeneous (linearnonlinear)

D a matrix (rotation andor scaling) flux D a matrix (rotation andor scaling) flux and gradient are generally not paralleland gradient are generally not parallel Anisotropic diffusionAnisotropic diffusion Eigenvectors of D determine the diffusion Eigenvectors of D determine the diffusion

directiondirection

Linear Diffusion FiltersLinear Diffusion Filters

Homogeneous case D = 1Homogeneous case D = 1

Initial condition u(x0) = f(x)Initial condition u(x0) = f(x) Unique solutionUnique solution

Linear Diffusion FiltersLinear Diffusion Filters

rarr

HL

IHL

Linear Diffusion FiltersLinear Diffusion Filters

Inhomogeneous case Inhomogeneous case Decrease blurring of the important Decrease blurring of the important

featuresfeatures Spatial adaptation rarr Reduce diffusion Spatial adaptation rarr Reduce diffusion

at the edgesat the edges D = g(D = g() monotonically decrease with ) monotonically decrease with

increasing parameterincreasing parameter Gradient of f as the fuzzy edge detectorGradient of f as the fuzzy edge detector

Result

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Incorporate adaptation based on the current Incorporate adaptation based on the current filtered image instead of the initial imagefiltered image instead of the initial image Spatial and temporal adaptationSpatial and temporal adaptation

D = g(D = g()) g a function of ug a function of u

High contrast region low diffusionHigh contrast region low diffusion Low contrast region high diffusionLow contrast region high diffusion

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

CharbonnierCharbonnier

Perona-MalikPerona-Malik

λλ contrast parameter to discriminate contrast parameter to discriminate noise from edgesnoise from edges

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

High noise in gradient High noise in gradient Instability suppresion of important Instability suppresion of important

image featuresimage features Unnecessary suppression of diffusion Unnecessary suppression of diffusion

(noise remains)(noise remains) Regularization Smooth the gradient Regularization Smooth the gradient

before adaptationbefore adaptation

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

t = 1500t = 40 t = 400t = 0EEOriginal PM R-PM

R-PM

rarr

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Canny PM

Original PM

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 2: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

IntroductionIntroduction

Filters for enhancement restoration Filters for enhancement restoration smoothing and feature extractionsmoothing and feature extraction

Varying for each data entry based on Varying for each data entry based on local featureslocal features u u = [u(0)u(1)u(n-1)u(n)]= [u(0)u(1)u(n-1)u(n)] ww = [ = [ww0 0 w w1 1 w wn-1 n-1 w wn n ]]

wwi i = [w= [wii(0) w(0) wii(1) w(1) wii(m-1) w(m-1) wii(m) ] (m) ]

Mean-value preservingMean-value preserving

Physics of DiffusionPhysics of Diffusion

Fickrsquos LawFickrsquos Law Continuity Continuity

Diffusion EquationDiffusion Equation

Gradient (uGradient (uxx u uyy) )

Divergence div Divergence div ΨΨ = = ΨΨ xx + + ΨΨ yy

Concentration replaced by data valuesConcentration replaced by data values

FluxDiffusion Tensor

Gradient

Concentration

Diffusion FiltersDiffusion Filters

D a scalar (flux and gradient are parallel)D a scalar (flux and gradient are parallel) Isotropic diffusion Isotropic diffusion D spatially invariant (fixed) Homogeneous D spatially invariant (fixed) Homogeneous

linear linear D = g(D = g() Inhomogeneous (linearnonlinear)) Inhomogeneous (linearnonlinear)

D a matrix (rotation andor scaling) flux D a matrix (rotation andor scaling) flux and gradient are generally not paralleland gradient are generally not parallel Anisotropic diffusionAnisotropic diffusion Eigenvectors of D determine the diffusion Eigenvectors of D determine the diffusion

directiondirection

Linear Diffusion FiltersLinear Diffusion Filters

Homogeneous case D = 1Homogeneous case D = 1

Initial condition u(x0) = f(x)Initial condition u(x0) = f(x) Unique solutionUnique solution

Linear Diffusion FiltersLinear Diffusion Filters

rarr

HL

IHL

Linear Diffusion FiltersLinear Diffusion Filters

Inhomogeneous case Inhomogeneous case Decrease blurring of the important Decrease blurring of the important

featuresfeatures Spatial adaptation rarr Reduce diffusion Spatial adaptation rarr Reduce diffusion

at the edgesat the edges D = g(D = g() monotonically decrease with ) monotonically decrease with

increasing parameterincreasing parameter Gradient of f as the fuzzy edge detectorGradient of f as the fuzzy edge detector

Result

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Incorporate adaptation based on the current Incorporate adaptation based on the current filtered image instead of the initial imagefiltered image instead of the initial image Spatial and temporal adaptationSpatial and temporal adaptation

D = g(D = g()) g a function of ug a function of u

High contrast region low diffusionHigh contrast region low diffusion Low contrast region high diffusionLow contrast region high diffusion

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

CharbonnierCharbonnier

Perona-MalikPerona-Malik

λλ contrast parameter to discriminate contrast parameter to discriminate noise from edgesnoise from edges

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

High noise in gradient High noise in gradient Instability suppresion of important Instability suppresion of important

image featuresimage features Unnecessary suppression of diffusion Unnecessary suppression of diffusion

(noise remains)(noise remains) Regularization Smooth the gradient Regularization Smooth the gradient

before adaptationbefore adaptation

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

t = 1500t = 40 t = 400t = 0EEOriginal PM R-PM

R-PM

rarr

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Canny PM

Original PM

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 3: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Physics of DiffusionPhysics of Diffusion

Fickrsquos LawFickrsquos Law Continuity Continuity

Diffusion EquationDiffusion Equation

Gradient (uGradient (uxx u uyy) )

Divergence div Divergence div ΨΨ = = ΨΨ xx + + ΨΨ yy

Concentration replaced by data valuesConcentration replaced by data values

FluxDiffusion Tensor

Gradient

Concentration

Diffusion FiltersDiffusion Filters

D a scalar (flux and gradient are parallel)D a scalar (flux and gradient are parallel) Isotropic diffusion Isotropic diffusion D spatially invariant (fixed) Homogeneous D spatially invariant (fixed) Homogeneous

linear linear D = g(D = g() Inhomogeneous (linearnonlinear)) Inhomogeneous (linearnonlinear)

D a matrix (rotation andor scaling) flux D a matrix (rotation andor scaling) flux and gradient are generally not paralleland gradient are generally not parallel Anisotropic diffusionAnisotropic diffusion Eigenvectors of D determine the diffusion Eigenvectors of D determine the diffusion

directiondirection

Linear Diffusion FiltersLinear Diffusion Filters

Homogeneous case D = 1Homogeneous case D = 1

Initial condition u(x0) = f(x)Initial condition u(x0) = f(x) Unique solutionUnique solution

Linear Diffusion FiltersLinear Diffusion Filters

rarr

HL

IHL

Linear Diffusion FiltersLinear Diffusion Filters

Inhomogeneous case Inhomogeneous case Decrease blurring of the important Decrease blurring of the important

featuresfeatures Spatial adaptation rarr Reduce diffusion Spatial adaptation rarr Reduce diffusion

at the edgesat the edges D = g(D = g() monotonically decrease with ) monotonically decrease with

increasing parameterincreasing parameter Gradient of f as the fuzzy edge detectorGradient of f as the fuzzy edge detector

Result

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Incorporate adaptation based on the current Incorporate adaptation based on the current filtered image instead of the initial imagefiltered image instead of the initial image Spatial and temporal adaptationSpatial and temporal adaptation

D = g(D = g()) g a function of ug a function of u

High contrast region low diffusionHigh contrast region low diffusion Low contrast region high diffusionLow contrast region high diffusion

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

CharbonnierCharbonnier

Perona-MalikPerona-Malik

λλ contrast parameter to discriminate contrast parameter to discriminate noise from edgesnoise from edges

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

High noise in gradient High noise in gradient Instability suppresion of important Instability suppresion of important

image featuresimage features Unnecessary suppression of diffusion Unnecessary suppression of diffusion

(noise remains)(noise remains) Regularization Smooth the gradient Regularization Smooth the gradient

before adaptationbefore adaptation

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

t = 1500t = 40 t = 400t = 0EEOriginal PM R-PM

R-PM

rarr

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Canny PM

Original PM

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 4: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Diffusion FiltersDiffusion Filters

D a scalar (flux and gradient are parallel)D a scalar (flux and gradient are parallel) Isotropic diffusion Isotropic diffusion D spatially invariant (fixed) Homogeneous D spatially invariant (fixed) Homogeneous

linear linear D = g(D = g() Inhomogeneous (linearnonlinear)) Inhomogeneous (linearnonlinear)

D a matrix (rotation andor scaling) flux D a matrix (rotation andor scaling) flux and gradient are generally not paralleland gradient are generally not parallel Anisotropic diffusionAnisotropic diffusion Eigenvectors of D determine the diffusion Eigenvectors of D determine the diffusion

directiondirection

Linear Diffusion FiltersLinear Diffusion Filters

Homogeneous case D = 1Homogeneous case D = 1

Initial condition u(x0) = f(x)Initial condition u(x0) = f(x) Unique solutionUnique solution

Linear Diffusion FiltersLinear Diffusion Filters

rarr

HL

IHL

Linear Diffusion FiltersLinear Diffusion Filters

Inhomogeneous case Inhomogeneous case Decrease blurring of the important Decrease blurring of the important

featuresfeatures Spatial adaptation rarr Reduce diffusion Spatial adaptation rarr Reduce diffusion

at the edgesat the edges D = g(D = g() monotonically decrease with ) monotonically decrease with

increasing parameterincreasing parameter Gradient of f as the fuzzy edge detectorGradient of f as the fuzzy edge detector

Result

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Incorporate adaptation based on the current Incorporate adaptation based on the current filtered image instead of the initial imagefiltered image instead of the initial image Spatial and temporal adaptationSpatial and temporal adaptation

D = g(D = g()) g a function of ug a function of u

High contrast region low diffusionHigh contrast region low diffusion Low contrast region high diffusionLow contrast region high diffusion

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

CharbonnierCharbonnier

Perona-MalikPerona-Malik

λλ contrast parameter to discriminate contrast parameter to discriminate noise from edgesnoise from edges

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

High noise in gradient High noise in gradient Instability suppresion of important Instability suppresion of important

image featuresimage features Unnecessary suppression of diffusion Unnecessary suppression of diffusion

(noise remains)(noise remains) Regularization Smooth the gradient Regularization Smooth the gradient

before adaptationbefore adaptation

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

t = 1500t = 40 t = 400t = 0EEOriginal PM R-PM

R-PM

rarr

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Canny PM

Original PM

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 5: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Linear Diffusion FiltersLinear Diffusion Filters

Homogeneous case D = 1Homogeneous case D = 1

Initial condition u(x0) = f(x)Initial condition u(x0) = f(x) Unique solutionUnique solution

Linear Diffusion FiltersLinear Diffusion Filters

rarr

HL

IHL

Linear Diffusion FiltersLinear Diffusion Filters

Inhomogeneous case Inhomogeneous case Decrease blurring of the important Decrease blurring of the important

featuresfeatures Spatial adaptation rarr Reduce diffusion Spatial adaptation rarr Reduce diffusion

at the edgesat the edges D = g(D = g() monotonically decrease with ) monotonically decrease with

increasing parameterincreasing parameter Gradient of f as the fuzzy edge detectorGradient of f as the fuzzy edge detector

Result

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Incorporate adaptation based on the current Incorporate adaptation based on the current filtered image instead of the initial imagefiltered image instead of the initial image Spatial and temporal adaptationSpatial and temporal adaptation

D = g(D = g()) g a function of ug a function of u

High contrast region low diffusionHigh contrast region low diffusion Low contrast region high diffusionLow contrast region high diffusion

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

CharbonnierCharbonnier

Perona-MalikPerona-Malik

λλ contrast parameter to discriminate contrast parameter to discriminate noise from edgesnoise from edges

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

High noise in gradient High noise in gradient Instability suppresion of important Instability suppresion of important

image featuresimage features Unnecessary suppression of diffusion Unnecessary suppression of diffusion

(noise remains)(noise remains) Regularization Smooth the gradient Regularization Smooth the gradient

before adaptationbefore adaptation

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

t = 1500t = 40 t = 400t = 0EEOriginal PM R-PM

R-PM

rarr

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Canny PM

Original PM

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 6: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Linear Diffusion FiltersLinear Diffusion Filters

rarr

HL

IHL

Linear Diffusion FiltersLinear Diffusion Filters

Inhomogeneous case Inhomogeneous case Decrease blurring of the important Decrease blurring of the important

featuresfeatures Spatial adaptation rarr Reduce diffusion Spatial adaptation rarr Reduce diffusion

at the edgesat the edges D = g(D = g() monotonically decrease with ) monotonically decrease with

increasing parameterincreasing parameter Gradient of f as the fuzzy edge detectorGradient of f as the fuzzy edge detector

Result

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Incorporate adaptation based on the current Incorporate adaptation based on the current filtered image instead of the initial imagefiltered image instead of the initial image Spatial and temporal adaptationSpatial and temporal adaptation

D = g(D = g()) g a function of ug a function of u

High contrast region low diffusionHigh contrast region low diffusion Low contrast region high diffusionLow contrast region high diffusion

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

CharbonnierCharbonnier

Perona-MalikPerona-Malik

λλ contrast parameter to discriminate contrast parameter to discriminate noise from edgesnoise from edges

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

High noise in gradient High noise in gradient Instability suppresion of important Instability suppresion of important

image featuresimage features Unnecessary suppression of diffusion Unnecessary suppression of diffusion

(noise remains)(noise remains) Regularization Smooth the gradient Regularization Smooth the gradient

before adaptationbefore adaptation

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

t = 1500t = 40 t = 400t = 0EEOriginal PM R-PM

R-PM

rarr

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Canny PM

Original PM

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 7: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Linear Diffusion FiltersLinear Diffusion Filters

Inhomogeneous case Inhomogeneous case Decrease blurring of the important Decrease blurring of the important

featuresfeatures Spatial adaptation rarr Reduce diffusion Spatial adaptation rarr Reduce diffusion

at the edgesat the edges D = g(D = g() monotonically decrease with ) monotonically decrease with

increasing parameterincreasing parameter Gradient of f as the fuzzy edge detectorGradient of f as the fuzzy edge detector

Result

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Incorporate adaptation based on the current Incorporate adaptation based on the current filtered image instead of the initial imagefiltered image instead of the initial image Spatial and temporal adaptationSpatial and temporal adaptation

D = g(D = g()) g a function of ug a function of u

High contrast region low diffusionHigh contrast region low diffusion Low contrast region high diffusionLow contrast region high diffusion

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

CharbonnierCharbonnier

Perona-MalikPerona-Malik

λλ contrast parameter to discriminate contrast parameter to discriminate noise from edgesnoise from edges

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

High noise in gradient High noise in gradient Instability suppresion of important Instability suppresion of important

image featuresimage features Unnecessary suppression of diffusion Unnecessary suppression of diffusion

(noise remains)(noise remains) Regularization Smooth the gradient Regularization Smooth the gradient

before adaptationbefore adaptation

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

t = 1500t = 40 t = 400t = 0EEOriginal PM R-PM

R-PM

rarr

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Canny PM

Original PM

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 8: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Incorporate adaptation based on the current Incorporate adaptation based on the current filtered image instead of the initial imagefiltered image instead of the initial image Spatial and temporal adaptationSpatial and temporal adaptation

D = g(D = g()) g a function of ug a function of u

High contrast region low diffusionHigh contrast region low diffusion Low contrast region high diffusionLow contrast region high diffusion

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

CharbonnierCharbonnier

Perona-MalikPerona-Malik

λλ contrast parameter to discriminate contrast parameter to discriminate noise from edgesnoise from edges

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

High noise in gradient High noise in gradient Instability suppresion of important Instability suppresion of important

image featuresimage features Unnecessary suppression of diffusion Unnecessary suppression of diffusion

(noise remains)(noise remains) Regularization Smooth the gradient Regularization Smooth the gradient

before adaptationbefore adaptation

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

t = 1500t = 40 t = 400t = 0EEOriginal PM R-PM

R-PM

rarr

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Canny PM

Original PM

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 9: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

CharbonnierCharbonnier

Perona-MalikPerona-Malik

λλ contrast parameter to discriminate contrast parameter to discriminate noise from edgesnoise from edges

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

High noise in gradient High noise in gradient Instability suppresion of important Instability suppresion of important

image featuresimage features Unnecessary suppression of diffusion Unnecessary suppression of diffusion

(noise remains)(noise remains) Regularization Smooth the gradient Regularization Smooth the gradient

before adaptationbefore adaptation

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

t = 1500t = 40 t = 400t = 0EEOriginal PM R-PM

R-PM

rarr

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Canny PM

Original PM

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 10: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

High noise in gradient High noise in gradient Instability suppresion of important Instability suppresion of important

image featuresimage features Unnecessary suppression of diffusion Unnecessary suppression of diffusion

(noise remains)(noise remains) Regularization Smooth the gradient Regularization Smooth the gradient

before adaptationbefore adaptation

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

t = 1500t = 40 t = 400t = 0EEOriginal PM R-PM

R-PM

rarr

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Canny PM

Original PM

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 11: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

t = 1500t = 40 t = 400t = 0EEOriginal PM R-PM

R-PM

rarr

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Canny PM

Original PM

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 12: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Nonlinear Isotropic Nonlinear Isotropic FiltersFilters

Canny PM

Original PM

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 13: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Nonlinear Anisotropic Nonlinear Anisotropic FiltersFilters

So far adaptation is only done spatially So far adaptation is only done spatially andor temporally but diffusion direction is andor temporally but diffusion direction is fixedfixed

Adaptation of the diffusion orientationAdaptation of the diffusion orientation D is chosen as a matrix (scaling andor rotation)D is chosen as a matrix (scaling andor rotation)

Varying the diffusion direction over the Varying the diffusion direction over the image can preserveenhance localsemilocal image can preserveenhance localsemilocal featuresfeatures

Intraregion smoothing instead of Intraregion smoothing instead of interregion smoothinginterregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 14: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Edge Enhancing FilterEdge Enhancing Filter

Change the orientation and the Change the orientation and the strength of the diffusion at an edgestrength of the diffusion at an edge

Smooth along the edge boundarySmooth along the edge boundary Diffusion along the edgesDiffusion along the edges

ReduceStop diffusion across the ReduceStop diffusion across the edge (eg Orthogonal to the edge)edge (eg Orthogonal to the edge)

Intraregion smoothingIntraregion smoothing

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 15: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Edge Enhancing FilterEdge Enhancing Filter

Create a positive semidefinite diffusion Create a positive semidefinite diffusion tensor Dtensor D

Orthonormal eigenvectors of D Orthonormal eigenvectors of D υυ1 1 υυ2 2

Eigenvalues control the diffusion strengthEigenvalues control the diffusion strength 1)1)

2)2)

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 16: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Edge Enhancing FilterEdge Enhancing Filter

t = 1500t = 40 t = 400t = 0

t = 3000t = 250 t = 875t = 0

R-PM

EE

larr

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 17: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Coherence Enhancing Coherence Enhancing FilterFilter

Interrupted lines flows in addition Interrupted lines flows in addition to noiseto noise

Need to process line or coherent Need to process line or coherent flow-like structures complete gapsflow-like structures complete gaps

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 18: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Coherence Enhancing Coherence Enhancing FilterFilter

Orientations instead of directions Orientations instead of directions (invariance to sign changes in (invariance to sign changes in gradient)gradient)

Orientation feature Orientation feature Structure tensorStructure tensor

Create diffusion tensor as a function Create diffusion tensor as a function of structure tensor instead of the of structure tensor instead of the gradientgradient

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 19: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Coherence Enhancing Coherence Enhancing FilterFilter

JJρρ positive semidefinite rarr orthonormal positive semidefinite rarr orthonormal eigenvectors eigenvectors υυ1 1 υυ2 2 eigenvalues eigenvalues μμ11ge ge μμ22 ge ge 00

υυ1 1 orientation of the highest grey value orientation of the highest grey value fluctuationfluctuation

υυ2 2 preferred local orientation (lowest preferred local orientation (lowest fluctuation)fluctuation)

((μμ1 1 - - μμ22))22 a measure of local coherence a measure of local coherence Suppress diffusion along Suppress diffusion along υυ1 1

Smooth along the direction of Smooth along the direction of υυ2 2

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 20: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Coherence Enhancing Coherence Enhancing FilterFilter

Choose the same set of eigenvectors Choose the same set of eigenvectors for Dfor D

Set eigenvalues Set eigenvalues λλ11 λλ22 as as

((μμ1 1 - - μμ22 ) )22 large large λλ22 asymp 1 asymp 1

((μμ1 1 - - μμ22 ) )22 small small λλ22 asymp asymp άά

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 21: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Coherence Enhancing Coherence Enhancing FilterFilter

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 22: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Coherence Enhancing Coherence Enhancing FilterFilter

PMOriginal CE

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 23: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

ConclusionsConclusions

Fast and stable filtersFast and stable filters Highly flexible Highly flexible

Varying the parameters of the diffusion Varying the parameters of the diffusion tensor (orientation rotation strength)tensor (orientation rotation strength)

Incorporation of new features (texture Incorporation of new features (texture color etc)color etc)

Separate filters for each data entrySeparate filters for each data entry High performanceHigh performance

Thank youThank you

Questions Questions

Page 24: Diffusion Filters S. Derin Babacan Department of Electrical and Computer Engineering Northwestern University March 7, 2006 ECE 463 Term Project

Thank youThank you

Questions Questions