DIGITAL IMAGE PROCESSING INTRODUCTION Dr. Hatem Elaydi Electrical Engineering Department Islamic University of Gaza Fall 2015 Sep. 9, 2015
DIGITAL IMAGE PROCESSING
INTRODUCTION Dr. Hatem Elaydi
Electrical Engineering Department
Islamic University of Gaza
Fall 2015
Sep. 9, 2015
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Electromagnetic spectrum
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Sensor Array: CCD Imaging
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Image Formation Model
f(x,y)=i(x,y)r(x,y)+n(x,y)
0<f(x,y)<∞
0<i(x,y)<∞
0<r(x,y)<1 reflectance
illumination
Intensity – proportional to energy
radiated by a physical source
(“intrinsic images”)
n(x,y) noise
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Sampling and Quantization: 1D Case
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2D Sampling and Quantization
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Introduction to Grayscale Images
Image representation
Spatial resolution
Bit-depth resolution
Local neighborhood
Block decomposition
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Image Represented by a Matrix
Spatial resolution
Bit-depth resolution
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Spatial Domain vs. Transform Domain
• Spatial domain
image plane itself, directly process the intensity values of
the image plane
• Transform domain
process the transform coefficients, not directly process
the intensity values of the image plane
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Spatial Domain Process
( , ) [ ( , )])
( , ) : input image
( , ) : output image
: an operator on defined over
a neighborhood of point ( , )
g x y T f x y
f x y
g x y
T f
x y
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Image Resampling
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Spatial Domain Process
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Spatial Resolution
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Commonly–used Terminology
Neighbors of a pixel p=(i,j)
N4(p)={(i-1,j),(i+1,j),(i,j-1),(i,j+1)} N8(p)={(i-1,j),(i+1,j),(i,j-1),(i,j+1),
(i-1,j-1),(i-1,j+1),(i+1,j-1),(i+1,j+1)}
Adjacency
4-adjacency: p,q are 4-adjacent if p is in the set N4(q)
8-adjacency: p,q are 8-adjacent if p is in the set N8(q)
Note that if p is in N4/8(q), then q must be also in N4/8(p)
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Euclidean distance
(2-norm)
D4 distance
(city-block distance)
D8 distance
(checkboard distance)
0 1 1
1
1
0 1 1
1
1
0 1 1
1
1 1 1
1 1
2 2 2 2 2
2
2
2
2 2 2 2
2
2
2
2
2
2
2
2
2
2
2
2 3
3
3
3 3
3
3
3 4
4 4
4 2
2 2
2
2 2
22
22
22 22
22
5
5
55
5
5
5 5
Common Distance Definitions
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