S. Mandayam/ DIP/ECE Dept./Rowan University

Digital Image ProcessingDigital Image Processing0909.452.01/0909.552.010909.452.01/0909.552.01

Fall 2003Fall 2003

Shreekanth MandayamECE DepartmentRowan University

http://engineering.rowan.edu/~shreek/fall03/dip/

Lecture 6Lecture 6October 13, 2003October 13, 2003

S. Mandayam/ DIP/ECE Dept./Rowan University

PlanPlan• Digital Image Restoration

• Recall: Environmental Models• Image Degradation Model• Image Restoration Model• Point Spread Function (PSF) Models

• Linear Algebraic Restoration• Unconstrained (Inverse Filter, Pseudoinverse Filter)• Constrained (Wiener Filter, Kalman Filter)

• Lab 3: Digital Image Restoration

S. Mandayam/ DIP/ECE Dept./Rowan University

DIP: DetailsDIP: Details

Gray-level Histogram

Spatial

DF T DC T

Spectral

Digital Image Characteristics

Point Processing M asking Filtering

Enhancem ent

Degradation M odels Inverse Filtering W iener Filtering

Restoration

Pre-Processing

Inform ation Theory

LZW (gif)

Loss less

Transform -based (jpeg)

Lossy

Com pression

Edge Detection

Segm entation

Shape Descriptors Texture M orphology

Description

Digital Im age Process ing

S. Mandayam/ DIP/ECE Dept./Rowan University

Image PreprocessingImage Preprocessing

Enhancement Restoration

SpatialDomain

SpectralDomain

Point Processing• >>imadjust• >>histeq

Spatial filtering• >>filter2

Filtering• >>fft2/ifft2• >>fftshift

• Inverse filtering• Wiener filtering

S. Mandayam/ DIP/ECE Dept./Rowan University

Degradation ModelDegradation Model

f(x,y) h(x,y) g(x,y)

n(x,y)

Degradation Model: g = h*f + n

demos/demo5blur_invfilter/demos/demo5blur_invfilter/degrade.m

S. Mandayam/ DIP/ECE Dept./Rowan University

Restoration ModelRestoration Model

f(x,y) DegradationModel f(x,y)Restoration

Filter

Unconstrained Constrained• Inverse Filter• Pseudo-inverse Filter

• Wiener Filter

demos/demo5blur_invfilter/

S. Mandayam/ DIP/ECE Dept./Rowan University

ApproachApproach

demos/demo5blur_invfilter/

f(x,y)

Builddegradation model

Formulate restoration algorithms

f(x,y)

Analyze usingalgebraic techniques

Implement usingFourier transforms

g = h*f + n

g = Hf + nW -1 g = DW -1 f + W -1 n

f = H -1 g

F(u,v) = G(u,v)/H(u,v)

S. Mandayam/ DIP/ECE Dept./Rowan University

Degradation & Restoration Examples: Gonzalez & WoodsDegradation & Restoration Examples: Gonzalez & WoodsAtmospheric Turbulence Model

S. Mandayam/ DIP/ECE Dept./Rowan University

Degradation & Restoration Examples: Gonzalez & WoodsDegradation & Restoration Examples: Gonzalez & WoodsExample 5.11: Inverse Filtering

S. Mandayam/ DIP/ECE Dept./Rowan University

Degradation & Restoration Examples: Gonzalez & WoodsDegradation & Restoration Examples: Gonzalez & WoodsExample 5.12: Wiener Filtering

S. Mandayam/ DIP/ECE Dept./Rowan University

Degradation & Restoration Examples: Gonzalez & WoodsDegradation & Restoration Examples: Gonzalez & WoodsExample 5.10: Planar Motion Model

S. Mandayam/ DIP/ECE Dept./Rowan University

Degradation & Restoration Examples: Gonzalez & WoodsDegradation & Restoration Examples: Gonzalez & WoodsExample 5.13: Inverse and Wiener Filtering

S. Mandayam/ DIP/ECE Dept./Rowan University

Lab 3: Digital Image Lab 3: Digital Image RestorationRestoration

http://engineering.rowan.edu/~shreek/fall03/dip/lab3.html

S. Mandayam/ DIP/ECE Dept./Rowan University

SummarySummary