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Adaptive Data Hiding
in Edge Areas of Images
With Spatial LSB Domain Systems
Adviser: Chih-Hung Lin
Speaker：Chia-Wei Chang
Date:2009/10/06
1
Introduce of Authors
•
Author:Cheng-Hsing Yang, Chi-Yao Weng, Shiuh-Jeng Wang and HungMin Sun.
•
IEEE Transactions on Information Forensics and Security, vol. 3, no. 3,
september 2008.
•
C.-H. Yang is with the Department of Computer Science, National
Pingtung University of Education, Pingtung, 900, Taiwan.
•
C.-Y. Weng and H. M. Sun are with the Department of Computer Science,
National Tsing-Hua University, Hsinchu, 300, Taiwan, R.O.C.
•
S.-J. Wang, corresponding author, is with the Department of Information
Management, Central Police University, Taoyuan, 333, Taiwan, R.O.C.
•
Manuscript received November 1, 2007; revised March 12, 2008.
Published August 13, 2008 (projected).
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Outline
• Introduction
• Literature Review
• Proposed Method


Embedding Procedure
Data Extraction
• Experimental Results
• Conclusions
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I.Introduction
4
I.Introduction
•Embedding
=
embedding
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I.Introduction
• In 2003, Wu and Tsai proposed a “PVD”.
• In2004, Chang and Tseng proposed a
side-match method.
• In 2005, Park et al. proposed a
steganographic scheme based
of neighboring pixels.
• In 2005, Wu et al. proposed the pixel-value
differencing (PVD) and LSB
replacement method.
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I.Introduction
• LSB techniques
• PVD techniques
• Side-Match techniques
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LSB method
Fig.1:Wu et al.’s division of “lower level” and
“higher level” (Div=15)
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II. Literature Review
• Wu et al.’s PVD and LSB
START
nonoverlapping
blocks with two
consecutive pixels
( pi' , pi' 1 )  ( pi , pi 1 )
( pi' , pi' 1 )  ( pi , pi 1 )
Emdedded by the 3b LSB
Emdedded by the 3b LSB
if : d i'  level
if : d i'  level
=
d i  level
=
d i  level
d i | pi  pi 1 |
if : d i  Div
N
N
Y
d i belongs to
d i belongs to
the higher level
the lower level
( pi' , pi' 1 ) 
N

( p i'  8, p i' 1  8 ), if : p i/  p i' 1
( p i'  8, p i' 1  8 ), if : p i/  p i' 1
Y
Y
END
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II. Literature Review
• Example
Div  15, pi  56, pi 1  47
and
sec ret data b  11000( 2)
di =|56-47|=9 (lower-level)
To embed 111000
p i' =63, pi' 1 =40
d i' =23>Div=15
'
If d i level≠ d ilevel
(p , p ) 

p i' =55, pi' 1 =48
d i' =55-48=7
'
i
'
i 1
( p i'  8, p i' 1  8 ), if : p i/  p i' 1
( p i'  8, p i' 1  8 ), if : p i/  p i' 1
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III.Proposed Method
• 2-3 Division and 3-4-5 Division
(a)
(b)
Fig. 2. Two dividing cases: (a) “lower level” and “higher level” and (b) “lower
level,” “middle level,” and “higher level.”
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III.Proposed Method
• 2-3 Division
lh
l  log 2 | R1 | and h  log 2 | R2 |
• 3-4-5 Division
lmh
l  log 2 | R1 |, m  log 2 | R2 | and h  log 2 | R3 |
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III-1.Embedding steps for l-m-h
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III-1.Embedding steps for l-m-h
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III-1.Embedding steps for l-m-h
• Case6.1
d i =L-level d i' ≠L-level
pi'  pi' 1
( pi' , pi' 1 )  ( pi' , pi' 1  2 k )or ( pi'  2 k , pi' 1 )
pi'  pi' 1
pi'  pi' 1
( pi' , pi' 1 )  ( pi' , pi' 1  2 k )or ( pi'  2 k , pi' 1 )
'
=M-level i =L-level
i
( pi' , pi' 1 )  ( pi'  2 k , pi' 1 )or ( pi' , pi' 1  2 k )
pi'  pi' 1
( pi' , pi' 1 )  ( pi' , pi' 1  2 k )or ( pi'  2 k , pi' 1 )
• Case6.2
• Case6.3
pi'  pi' 1
pi'  pi' 1
• Csae6.4
d
d
d i =M-level d i' =H-level
( pi' , pi' 1 )  ( pi' , pi' 1  2 k )or ( pi'  2 k , pi' 1 )
( pi' , pi' 1 )  ( pi' , pi' 1  2 k )or ( pi'  2 k , pi' 1 )
d i =H-level d i' ≠H-level
pi'  pi' 1
( pi' , pi' 1 )  ( pi' , pi' 1  2 k )or ( pi'  2 k , pi' 1 )
pi'  pi' 1
( pi' , pi' 1 )  ( pi' , pi' 1  2 k )or ( pi'  2 k , pi' 1 )
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III-1 Embedding Procedure
Example
Div  15, pi  64, pi 1  47
and
sec ret data b  10100000( 2)
di =|64-47|=17 (middle-level)
To embed 4-bit LSB
p i' =74, pi' 1 =32
d i' =42
After the modified LSB substitution is applied
p i' =58, pi' 1 =48 d i' =10
'
di =M-level d i =L-level
pi'  pi' 1
( pi' , pi' 1 )  ( pi'  2 k , pi' 1 )or ( pi' , pi' 1  2 k )
pi'  pi' 1
( pi' , pi' 1 )  ( pi' , pi' 1  2 k )or ( pi'  2 k , pi' 1 )
p i' =74, pi' 1 =48
d i' =|74-48|=26
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III-2.Data Extraction
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III-2.Data Extraction Example
p i' =74, pi' 1 =48
d i' =|74-48|=26
There are 4 bits embedded in
p i' ‘s
secret bits
pi' 1‘s
secret bits
p
'
i and 4 bits embedded in
p
'
i 1
1010 ( 2 )
0000( 2)
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IV.Experimental Results
Fig. 3:Two cover images.
(a) Elaine. (b) Baboon.
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IV.Experimental Results
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IV.Experimental Results
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IV.Experimental Results
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IV.Experimental Results
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V.Conclusions
• some l-h divisions and l-m-h divisions both
yielded higher capacity and higher PSNR.
• Embed secret data into gray images without
making a perceptible distortion.
• Can be analyzed automatically, aiming to
capture an adequate - - division satisfying the
key requirements in information hiding.
• Experimental results show that our approach
obtains both larger capacity and higher image
quality than that of Wu et al.
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