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A robust detection algorithm for copymove forgery in digital images
1
Source:
Authors:
Forensic Science International, Volume 214,
Issues 1–3, 10 January 2012
Yanjun Cao, Tiegang Gao, Li Fan, Qunting
Yang
Presenter: Li-Ting Liao
Date:
2012/06/14
OUTLINE
2
Introduction
Proposed Scheme
Experimental Results
Conclusions
Introduction
3
Copy-move
forgery
Original image
Tamper image
detect
Proposed Scheme
4
Flowchart of the proposed scheme
THE PROPOSED SCHEME – Block Dividing (1/2)
5
B
B
B
Generate
B
N
N
(N-B+1)(N-B+1) Blocks
THE PROPOSED SCHEME –Block Dividing (2/2)
6
155 155 155 158
Block size : 4 × 4
155 155 155 158 158 156 158 159
155 155 155 158 158 156 158 159
155 155 155 158
155 155 155 158
155 155 155 158
155 155 155 158 158 156 158 159
155 155 158 158
155 155 155 158 158 156 158 159
155 155 158 158
155 155 155 158 158 156 158 159
155 155 158 158
151 151 151 154 157 156 156 156
155 155 158 158
155 155 155 156 157 158 156 153
149 149 149 153 155 154 153 154
Original image
…
158 156 158 159
157 156 156 156
157 158 156 153
155 154 153 154
THE PROPOSED SCHEME – DCT transform
7
155
155
155
158
155
155
155
158
155
155
155
158
155
155
155
158
Original block
DCT
Transform
420.75 37.70297
-3.25 4.136577
-2.98619 0.926777
2.1744 -0.32322
-0.25 -5.44081
0.75 -0.72292
2.589912 0.676777 -0.63007 0.573223
DCT coefficient block
THE PROPOSED SCHEME – Feature extraction (1/2)
8
420.75 37.70297
C1
-3.25 4.136577
C2
-2.98619 0.926777
2.1744 -0.32322
-0.25 -5.44081
0.75 -0.72292
C4
C3
2.589912 0.676777 -0.63007 0.573223
DCT coefficient block
Generate matching feature ：
f
x
,
y
v
,
(
f
x
,
y
c
_
a
r
e
a
,
i
1
,
2
,
3
,
4
)
i
i
c
_
a
r
e
a
i
f
e
a
t
u
r
e
v
e
c
t
o
r
:
V
v
,
v
,
v
,
v
1234
THE PROPOSED SCHEME – Feature extraction (2/2)
9
Generate matching feature ：
r
2
420.75 37.70297
C1
-2.98619 0.926777
-0.25 -5.44081
C4
-3.25 4.136577
C2
2.1744 -0.32322
0.75 -0.72292
C3
2.589912 0.676777 -0.63007 0.573223
DCT coefficient block
2
c
_
a
r
e
a
r
4
c
_
a
r
e
a
4
/4
fo
r
i
1
,2
,
3
,4
i
4
2
0
.
7
5
3
7
.
7
0
2
9
7
2
.
9
8
6
1
9
0
.
9
2
6
7
7
7
≒ 145.2746
v
1
(
3
.
2
5
)
4
.
1
3
6
5
7
7
2
.
1
7
4
4
(
0
.
3
2
3
2
2
)
≒ 0.8715
v
0
.
7
5
(
0
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7
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2
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)
(
0
.
6
3
0
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7
)
0
.
5
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3
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2
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≒ -0.0095
v
2
3
(
0
.
2
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)
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5
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4
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0
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2
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9
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1
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0
.
6
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6
7
7
7
≒ -0.7716
v
4
f
e
a
t
u
r
e
v
e
c
t
o
r
:
V
v
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,
v
,
v
1234
V
[
1
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,
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.
8
7
1
5
,
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.
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5
,
0
.
7
7
1
6
]
1
THE PROPOSED SCHEME – Matching (1/3)
10
V1
V
2
A
V
(NB1)(NB1)
1
4
k k2
i
i
j
s
i
m
i
l
a
r
k
1
m
_
m
a
t
c
h
(
A
,
A
)
(
v
v
)D
i
i
j
2
(x2, y2)
d
2
Similar condition ：
d
(
V
,
V
)
x
x
y
y
N
i
i
j
i
i
j
i
i
j
d
(x1, y1)
2X2
P
r
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d
i
c
tv
a
l
u
e
:
D
,N
s
i
m
i
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a
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2X2
2
THE PROPOSED SCHEME – Matching (2/3)
11
1
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1
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,
0
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A
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.1
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P
re
d
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c
tv
a
l
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e
:
D
0
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,N
2
5
s
i
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a
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d
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Dsimilar
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5
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6
Not
Similar
2
2
2
2
Dsimilar
m
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h
(
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0
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7
THE PROPOSED SCHEME – Matching (3/3)
12
1
4
5
.2
7
4
6
,0
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7
1
5
,
0
.0
0
9
5
,
0
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7
1
6
A
1
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6
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8
1
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6
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2
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.
1
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3
,
0
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9
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7
1
,
0
.
0
0
3
2
,
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1
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.2
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3
4
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0
1
5
,
0
.4
9
6
8
,4
.1
9
0
4
V1 (1,1)
V
(100,81
)
117
P
r
e
d
i
c
t
v
a
l
u
e
:
D
0
.
4
,
N
2
5
s
i
m
i
l
a
r
d
2
2
2
2
Dsimilar
m
_
m
a
t
c
h
(
A
,
A
)
(
1
4
5
.
2
7
4
6
1
4
5
.
1
6
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3
)
(
0
.
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)
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1
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1
7
d
(
V
,
V
)
1
1
0
0
1
8
1
≒ 127.28
11
1
7
2
2
Nd 5
Similar
Detected image
EXPERIMENTAL RESULTS(1/6)
13
The detection results (from left to right is the original image, tampered image,
detection results).
EXPERIMENTAL RESULTS(2/6)
14
The detection results for non-regular copy-move forgery
EXPERIMENTAL RESULTS(3/6)
15
The test results for multiple copy-move forgery under a mixed
operation
EXPERIMENTAL RESULTS(4/6)
16
The top row are tampered images with duplicated region size of 32 pixels × 32
pixels. Shown below are the detection results using our algorithm
EXPERIMENTAL RESULTS(5/6)
17
(a)
(b)
DAR curves for DCT, DCT-improved, PCA, FMT, and Proposed methods when
the duplicated region is 64 pixels 64 pixels. (a) Gaussian noise, and (b) Gaussian
blurring
EXPERIMENTAL RESULTS(6/6)
18
[2] A. Fridrich, et al., Detection of Copy-move Forgery in Digital Images, 2003.
[3] Y. Huang, et al., Improved DCT-based detection of copy-move forgery in
images, Forensic Science International 206 (1–3) (2011) 178–184.
[4] A. Popescu and H. Farid, Exposing digital forgeries by detecting duplicated
image regions, Dept. Comput. Sci., Dartmouth College, Tech. Rep. TR2004515,
2004.
CONCLUSIONS
19
This paper presented an automatic and efficient detection
algorithm for copy-move forgery
The proposed algorithm could not only endure the multiple
copy-move forgery, but also the blurring or nosing adding