1. Subject Name: IMAGE PROCESSING Subject Code: 10EC763
Prepared By: K.PRAVEENA
Department: ECE
Date:
1/3/2019

2. UNIT - 2
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3. Image sensing and acquisition Image formation model
Topics covered:
Image sensing and acquisition
Image formation model
Representation of Digital Images
Image zooming and shrinking
Relation ship between pixels
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4. Light and the Electromagnetic Spectrum
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5. Image sensing using single sensor
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6. Image sensing
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7. Image sensing using single sensor
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8. Image formation model
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9. Image formation model Image is a 2 dimensional function of form f(x,y)
Amplitude of f at spatial coordinates (x,y) is a positive scalar quantity.
f(x,y) must be a non zero and finite i.e
0< f(x,y)<∞
The function f(x,y) is defind by two functions
Amount of source illumination incident on the scene
Amount of the illumination reflected by object
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10. These are called illumination i(x,y)and reflection r(x,y) components.
f(x,y)= i(x,y)* r(x,y)
0< i(x,y)< ∞
0<r(x,y) < 1
0 is total absorption
1 total reflection
Let intensity of the monochrome image at (x0 , y0 ) the gray level of the image at that point is as follows
l = f (x0 , y0 )
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11. Lmin≤l ≤Lmax theoritically Lmin is +ve value and Lmax is infinite
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12. Sampling and quantization
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13. Sampling and quantization
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14. Representing digital images
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15. Spatial and gray-level resolution
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16. Subsampled and resampled
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17. Varying the number of gray levels
Orignal
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18. Low Medium High level detail image
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19. Zooming and shrinking
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20. Some Basic Relationships Between Pixels
Neighbors of a pixel
4-neighbors of p
four diagonal neighbors of p
8-neighbors of p
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21. Adjacency
m-adjacency (mixed adjacency): Two pixels p and q with values from V are m-adjacency if
q is in N4(P) or
q is in ND(P) and the set N4(P) intersection of N4(q) has no pixels whose values are from V
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22. Subset adjacency
S1 and S2 are adjacent if some pixel in S1 is adjacent to some pixel in S2
Path
A path from p with coordinates (x,y) to pixel q with coordinates (s,t) is a sequence of distinct pixels with coordinates
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23. Region
We call R a region of the image if R is a connected set
Boundary
The boundary of a region R is the set of pixels in the region that have one or more neighbors that are not in R
Edge
Pixels with derivative values that exceed a preset threshold
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24. Distance measures Euclidean distance City-block distance
Chessboard distance
Linear operation
H is said to be a linear operator if, for any two images f and g and any two scalars a and b,
H ( af + bg ) = H a(f)+ H b(g)
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