Improved Reduced Difference Expansion Based Reversible Data Hiding

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  Improved Reduced Difference
Expansion Based Reversible Data
Hiding Scheme for Digital Images




 Source:ICEMI '09. 9th International Conference on Electronic
            Measurement & Instruments, 2009.
            Authors:Hu Yi, Song Wei, Hou Jianjun
                     Speaker:Cheng Hsu
                      Date:2010/12/15
                          多媒體網路安全實驗室

                Outline
1.   Introduction
2.   Related works
3.   Proposed scheme
4.   Experiment results
5.   Conclusions




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               1.Introduction
In this paper, a new reversible data hiding based
 on logarithm transformation function named
 improved reduced difference expansion (IRDE)
 was proposed.

They change the embedding step by using an
 improved logarithm transformation function to
 reduce the distortion by difference expansion
 further more.


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      2. Related works
        Tian’s method Embedding phase
( x,y)  (126,100)
     x  y  126  100   226 
l                         2   113
     2             2           
h  x  y  126  100  26
secret data b  0
h'  2  h  b  2  26  0  52
the new piexls ( x' , y ' )
           h'1           52  1
x'  l           113           113  26  139
           2              2 
           h'         52 
y '  l     113     113  26  87
          2          2
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                 Extracting phase
( x' , y ' )  (139,87)
     x' y '  139  87   226 
l              2    2   113
     2                       
h'  x' y '  139  87  52
b  LSB(h' )  LSB(52)  0
     h'   52 
h        26
    2  2 
         h  1          26  1
xl            113   2   113  13  126
         2                    
        h          26 
y  l     113     113  13  100
        2          2 5
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                           Lou’s method Embedding phase
( x, y )  (126,100)                                           h                  if h  2
                                                          h'  
    x  y  126  100                                       h  2 log 2 h 1 otherwise
l                     113
    2            2    
                                                                 0 if 2 log 2 h '   2 log 2 h 
                                                                 
h  x  y  126  100  26                                  LM  
                                                                 1 if 2 log 2 h '   2 log 2 h 
h'  h  2 log 2 h 1
                         26  2 log 2 26 1
                                                26  2  18 
                                                       4 1


LM  0
secret data b  0
h"  2  h'b  2 18  0  36
           h"1           36  1
x'  l           113   2   113  18  131
           2                    
           h"          36 
y '  l     113     113  18  95
          2           2          6
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                                       Extracting phase
( x' , y ' )  (131,95)
     x' y '  131  95   226                    h'2 log 2 h ' if LM  1
                                                      
l              2    2   113               h
     2                                          h'2 log 2 h '1 if LM  0
                                                      
h"  x' y '  131  95  36
b  LSB(h" )  LSB(36)  0
      h"   36 
h'        18
     2 2
LM  0
h  h'2 log 2 h '1  18  2 41  26
         h  1          26  1
xl            113           113  13  126
         2              2 
        h           26 
y  l     113     100
        2          2                    7
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                        3. Proposed scheme
                                      Embedding phase
( x, y )  (126,100)                               h  2 log 2 h 1 if 2  2 n 1  h  3  2 n 1  1
                                                   
                                              h'  
    x  y  126  100                           h  2 log 2 h  if 3  2 n 1  h  4  2 n 1  1
                                                   
l                     113
    2           2     
                                                          0 if 2  2 n 1  h  3  2 n 1  1
                                                          
h  x  y  126  100  26                           LM  
                                                          1 if 3  2 n 1  h  4  2 n 1  1
                                                          
h'  h  2 log 2 h   26  2 log 2 26   26  2 4  10
LM  1
secret data b  0
h"  2  h'b  2 10  0  20
           h"1           20  1
x'  l           113   2   113  10  123
           2                    
           h"          20 
y '  l     113     113  10  103
          2           2            8
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                                          Extracting phase
( x' , y ' )  (123,103)
     x' y '  123  103   226                            h'2 log 2 h ' 1 if LM  1
                                                               
l                         2   113                  h
     2             2                                     h'2 log 2 h '  if LM  0
                                                               
h"  x' y '  123  103  20
b  LSB(h" )  LSB(20)  0
      h"   20 
h'        10
     2  2 
LM  1
h  h'2 log 2 h '1  10  231  26
         h  1          26  1
xl            113           113  13  126
         2              2 
        h           26 
y  l     113     100
        2          2                       9
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4. Experiment results
  Embedding capacity and PSNR
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            5. Conclusions

They modify the embedding procedure
 and extraction procedure of Reduced
 Difference Expansion (RDE) scheme.

Their method not only improves the
 embedded image quality but also provides
 higher payload capacity than Lou’s
 method.


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