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A Blind Image Watermarking Scheme Based On Wavelet Tree Quantization

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A Blind Image Watermarking Scheme Based On Wavelet Tree Quantization Powered By Docstoc
					A Blind Image Watermarking Scheme
Based On Wavelet Tree Quantization
  Authors: Peng Liu, Zhizhong Ding
  Source: Electronic Commerce and Security, 2009.
           ISECS '09. Second International Symposium
           on Volume 1, 22-24 May 2009
  Speaker: Pei-Lin Tsou
  Date:     December 16, 2009
Outline
   Introduction
   Proposed Scheme
   Experimental Results
   Conclusions




                           2
Indroduction
    Wavelet Tree
                                  LL3 LH3
                                            LH2
                                  HL3 HH3
                                                  LH1
                                   HL2 HH2
                           DWT


                                      HL1         HH1



                            LH3
           -31


     15   14     -9   -7    LH2


-5    9    3      0        LH1
                                                        3
Proposed Scheme(1/4)
   Embedding
    Original Image             1                     512
                               LL3 LH3
                                         LH2
                               HL3 HH3
                     3-level                   LH1

                      DWT          HL2   HH2           LH3, HL3, k   Pseudorandam
                                                                        Function
                                     HL1       HH1




                                           1     64
                                                                      Embedding
                                                                       Process
                                         Watermark

                                                                                    4
Proposed Scheme(2/4)
   Embedding
     Embed a watermark bit = 1
               Maxi        , if  i  max( , T )
               
     Maxinew  Maxi      , if  i  max( , T ) and Maxi is a root
               Max     , if   max( , T ) and Max is not a root
                  i                i                     i
     i  Maxi  Seci
        1 N 
        i                   7
                                  27
                                  31
                                  5                    75  2
                                                  i  31  15  16
         N i 1 
                                                 16 max( T )) 10
                                                 2  max( , , T  10
       8
                                                 Maxi is a a31
                                                  Maxinewrootroot
                                                         not
      T  10
                        5
                        15
                        37
                        7    2
                             14        -9   -7    Maxinew  7  20 127  37
                                                                     .5
        20
        1 .5                                                                  5
Proposed Scheme(3/4)
   Embedding
       Embed a watermark bit = 0

         Maxinew  Seci

                -31

                                    Maxinew  14
          14
          15   14     -9   -7




                                                   6
Proposed Scheme(4/4)
    Watermarking Extracting
                        1 N a                                     1, if   y
    Threshold : y               j               Watermark bit         i
                        N  a j 1                                 0, if   y
                                                                               i
               
      Sort{1 , 2 , , N },   Maxi  Seci
                                   i


     a  0.6
     0   10   9    3    5    7    6    1    9   8   0   0   6   8    4   0

W     0    1   1    0    0    1    0    0    1   1   0   0   0   1    0   0

      {10,9,9,8,8,7,6,6,5,4,3,1,0,0,0,0}
       1 160.6  10  9  9  8  8  7  6  6  5 
    y          j                                7
      16  0.6 j 1             9.6                                         7
    Experimental Results
   Before Attack      After Attack
    PSNR=38.764




            NC=1

                                       8
Conclusions
   Blind watermarking scheme




                                9
Experimental Results




                       10

				
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