image processing tutorials

7/27/2019 Image Processing Tutorials

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D 2 E E


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CEI B

A

C

B

D

AD ADA

D... 2ADA

E


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CEII

G

()

(H)

AD ADA

D... 3ADA

E


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CEIII B

F

C

(G)

C

B

AD ADA

D... 4ADA

E


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CEIV H

H

H E

H

F F F

C C F

F

AD ADA

D... 5ADA

E


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B

1. 2. A

3. C

4.

5. B

6. D


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AD ADA

D... 7ADA

E


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A

AD ADA

D... 8ADA

E


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AD ADA

D... 9ADA

E


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C .

.

F ,

.

.

AD ADA

D... 10ADA

E


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.

.

AD ADA

D... 11ADA

E


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D

AD ADA

D... 12ADA

E

pp

ndp

dp

dp

d

p

D/1

....

321

++++=


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1.

2.

3. G

.

.

.

.

. ()

. (H)


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.

1.

AD ADA

D... 14ADA

E


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(,) ,.

, .

2.

AD ADA

D... 15ADA

E


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G IG

.

.

AD ADA

D... 16ADA

E


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G II

A IThe transformation coordinates may be expressed

as given in the following expression.

where (v,w) are pixel coordinates of the original image and (x,y) are pixel

coordinates of the transformed image.

AD ADA

D... 17ADA

E

(2.1)

1

0

0

]1,,[]1,,[]1,,[

)},{(),(

3231

2221

1211

==

=

tt

tt

tt

wvTwvyx

wvTyx


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G III

A IIIn practice we can use the equation (2.1) for

transformation in two basic ways the first is called

forward mapping and inverse mapping.

Forward Mapping consists of scanning the pixels of the input image

and at each location (v,w) computing the spatial location (x,y) of the

corresponding pixel in the output image directly. A problem with theforward mapping approach is that 2 or more pixels in the input image

may get mapped to the same location in the output image and it is also

possible that some output locations may not be assigned a pixel at all.

AD ADA

D... 18ADA

E


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G IV

A IIIInverse Mapping scans the output pixel locations

and at each location (x,y) computes the

corresponding location in the input image (v,w)

using the following expression.

AD ADA

D... 19ADA

E

(2.2))},{(),( 1 yxTwv =


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G V

A IVIdentity prog_3.m

AD ADA

D... 20ADA

E

=

100

010

001

T


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G VI

A VIdentity prog_4.m

AD ADA

D... 21ADA

E

Original Image

Transformed Image


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G VII

A VIRotation prog_5.m

AD ADA

D... 22ADA

E

=

100

0cossin

0sincos

T


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G VIII

A VIITranslation prog_6.m

AD ADA

D... 23ADA

E

=

1

010

001

yx tt

T


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G IX

A VIIIShear (Vertical) prog_7.m

AD ADA

D... 24ADA

E

=

10001

001

vsT


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G IX

A VIIIShear (Horizontal) prog_8.m

AD ADAD... 25

ADAE

=

100010

01 hs

T


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B

F

1. ( D1)

2.

C

3.

4. (G)

5. C 6.

7. B


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C

,1 .

s = L-1-k-r (2.3)where s is output intensity level and r is input intensity level

prog_9.m

AD ADAD... 27

ADAE


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.

s = c(log10(1+r)) (2.4)where s is output intensity level and r is input

intensity level and c is a constant.

prog_10.m

AD ADAD... 28

ADAE


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(G)

Power law transformation is given by the following expression.

prog_11.m

AD ADAD... 29

ADAE

(2.5)crs=


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C Contrast Stretching is a process that expands the

range of intensity levels in an image so that it spans

the full intensity range of the recording medium ordisplay device.

prog_12.m

AD ADAD... 30

ADAE


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Intensity-Level Slicing involves highlighting a

specific range of intensities in an image.

prog_13.m

AD ADAD... 31

ADAE


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B

AD ADAD... 32ADAE

14.


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H

1. H2. H E

3. H


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H

AD ADAD... 34ADAE

15.


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H E

AD ADAD... 35ADAE

16.


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H See example 3.7 Gonzalez and Woods

AD ADAD... 36ADAE


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F

F1. F

2. C

C

3. F

4. F


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F I

If the operation performed on the image pixels is

linear, then the filter is called a linear spatial filter.

Otherwise, the filter is nonlinear.

The general form of expression for linear filters is

given in the following expression.

AD ADAD... 38ADAE

(2.6)),(),(),( = = =

a

as

b

bt tysxftswyxg


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F II

Vector Representation of

Linear Filtering

AD ADAD... 39ADAE

zw

R

T

mn

k

kk

mnmn

zw

zwzwzwzw

=

=

++++=

=

(2.7)...

1

332211


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C C

Ref: Gonzalez and Woods , P.g.-> 148-149

prog_17.m prog_18.m

Correlation:-

Convolution:-

AD ADAD... 40ADAE

(2.8)),(),(),(

= =++=

a

as

b

bt

tysxftswyxg

(2.9)),(),(),( = =

=a

as

b

bt

tysxftswyxg


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C C

AD ADAD... 41ADAE

F


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F

AD ADAD... 42ADAE

(2.10)

111

111

111

9

1

=Mask

1.

F


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F

AD ADAD... 43ADAE

(2.11)11118-1

111

=Mask

20.


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AD. A C,

EEE (A)

A , E E D

, 700 032, .

.....

//.../.322

//.../170

&


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17 , 2014 2014 46

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