Transcript Digital Image Processing Lecture

S. Mandayam/ DIP/ECE Dept./Rowan University
Digital Image Processing
0909.452.01/0909.552.01
Fall 2003
Lecture 6
October 13, 2003
Shreekanth Mandayam
ECE Department
Rowan University
http://engineering.rowan.edu/~shreek/fall03/dip/
S. Mandayam/ DIP/ECE Dept./Rowan University
Plan
• 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: Details
D ig ital Im ag e Pro c es s ing
D ig ital Im a g e Ch a rac te ris tics
S p a tial
G ra y-le vel
S p ec tral
H is to g ram
DFT
DC T
P re -Pro c es s ing
E n h a n ce m e nt
P o in t P ro c es s ing
M a sk ing
R e s to ra tion
F ilte ring
D e g ra da tio n M o d e ls
In ve rs e F ilte ring
C o m p re s s ion
In fo rm a tio n T h e o ry
L o ss le ss
L o s sy
L Z W (g if)
T ra n s fo rm -ba s e d (jp e g)
S e g m e n ta tion
E d g e De te c tion
D e s c rip tion
S h a p e D e s crip to rs
T e x tu re
M o rp h o lo g y
W ie ne r F ilte ring
S. Mandayam/ DIP/ECE Dept./Rowan University
Image Preprocessing
Restoration
Enhancement
Spectral
Domain
Spatial
Domain
Point Processing
• >>imadjust
• >>histeq
Spatial filtering
• >>filter2
Filtering
• >>fft2/ifft2
• >>fftshift
• Inverse filtering
• Wiener filtering
S. Mandayam/ DIP/ECE Dept./Rowan University
Degradation Model
f(x,y)
h(x,y)
S
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 Model
f(x,y)
Degradation
Model
Restoration
Filter
Unconstrained
• Inverse Filter
• Pseudo-inverse Filter
f(x,y)
Constrained
• Wiener Filter
demos/demo5blur_invfilter/
S. Mandayam/ DIP/ECE Dept./Rowan University
f(x,y)
Build
degradation model
Analyze using
algebraic techniques
Formulate
restoration algorithms
Implement using
Fourier transforms
f(x,y)
Approach
g = h*f + n
g = Hf + n
W -1 g = DW -1 f + W -1 n
f = H -1 g
F(u,v) = G(u,v)/H(u,v)
demos/demo5blur_invfilter/
S. Mandayam/ DIP/ECE Dept./Rowan University
Degradation & Restoration Examples: Gonzalez & Woods
Atmospheric Turbulence Model
S. Mandayam/ DIP/ECE Dept./Rowan University
Degradation & Restoration Examples: Gonzalez & Woods
Example 5.11: Inverse Filtering
S. Mandayam/ DIP/ECE Dept./Rowan University
Degradation & Restoration Examples: Gonzalez & Woods
Example 5.12: Wiener Filtering
S. Mandayam/ DIP/ECE Dept./Rowan University
Degradation & Restoration Examples: Gonzalez & Woods
Example 5.10: Planar Motion Model
S. Mandayam/ DIP/ECE Dept./Rowan University
Degradation & Restoration Examples: Gonzalez & Woods
Example 5.13: Inverse and Wiener Filtering
S. Mandayam/ DIP/ECE Dept./Rowan University
Lab 3: Digital Image
Restoration
http://engineering.rowan.edu/~shreek/fall03/dip/lab3.html
S. Mandayam/ DIP/ECE Dept./Rowan University
Summary