high-capacity image hiding scheme based on vector quantization
DESCRIPTION
High-capacity image hiding scheme based on vector quantization. Authors: Yu-Chen Hu Source: Pattern Recognition, vol. 39, pp. 1715-1724, 2006 Speaker: Shu-Fen Chiou( 邱淑芬 ) Date: 2006/10/19. Outline. Introduction Proposed method Experimental results Conclusion Comment. - PowerPoint PPT PresentationTRANSCRIPT
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High-capacity image hiding scheme based on vector quantizationAuthors: Yu-Chen HuSource: Pattern Recognition, vol. 39, pp. 1715-1724, 2006Speaker: Shu-Fen Chiou(邱淑芬 )Date: 2006/10/19
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Outline
Introduction Proposed method Experimental results Conclusion Comment
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Introduction
This method is hiding multiple secret images into a host image of the same size.
The proposed scheme provides a higher hiding capacity.
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Hiding bits
1
log/ 2max hw
Nkhwsnor c
2753.1
1512512
128log16/5125124 2max
r
sno: total number of secret images
Nc: the size of VQ codebook
k: the vector dimension
rmax: The maximal number of modified bits
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Training codebook
.2 e with valu imagehost
in the pixeleach of bits last
thereplacingby generated be
can imagehost modified The
1
max
'
max rH
r
H
'HH
10110001 10110001 10110001 10110011
01100010 01101010 01100000 01100010
00111111 00111111 00111111 00111101
10000000 10011100 10110000 10011000
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max
)10(22
2max
r
r
10110010 10110010 10110010 10110010
01100010 01100010 01100010 01100010
00111110 00111110 00111110 00111110
10000010 10000010 10000010 10000010
'H
Random seed rs
Codebook is sorted by mean values of codewords
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VQ
Original image Index table
51 46 6 84 41 52 74 3
2 …
…
…
…
…
…
…
Codebook
012
255254253
(20,45,…,76)
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AAD
Design HCT
101 102 102
100 102 110
102 111 113
1
1
1
1
'' ),(),(8
1),(
s t
jihtjsihjiAAD
875.38/)100102102102111102113102
110102102102102102101102(
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Hiding
127 12801111111 10000000
Host pixel h(i,j)
s(i,j)=00
HCT(i,j)=2
b(i,j)=127 mod 22=3
d(i,j)=0-3=-3
-22+1<=d(i,j)
<-(22-1)/2=-1.5
d’(i,j)=-3+22=1
h’(i,j)
127+1
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Index compression
129 128 130
134 128
10 01 11
00 I(x)
Encode: ‘0’+’01’RANG=4
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Index compression
2/)1()(
4/
DISP
DISP
THxIxI
codebookTH
134 128I(x-1) I(x)
Encode: ‘10’+’1’+’00110’
2/64134128
644/256
DISPTH
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Index compression
230 230 220
220 128I(x)
Encode: ‘11’+’10000000’
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Encrypt
Compressed index table is encrypted by DES cryptosystem suing the secret key sk
W, h, sno, Nc, k, rs, pk, RANG, and ThDIST are encrypted by DES cryptosystem also using the same secret key sk
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The secret extraction procedure
Extract w, h, sno, Nc, two random seeds key rs and pk, RANG, THDIFF and determine rmax.
Generate the VQ codebook with Nc codeword using H' with random seed rs.
Obtain a serial of random number by pk. To rebuild the original index table by RANG a
nd THDIFF.
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Experimental results
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Experimental results
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Experimental results
Comparative storage cost (unit: bits) of the proposed scheme (PS) and the proposed scheme without index compression (PS').
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Experimental results
Provide an average of 1.304dB image quality gain.
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Experimental results
Image qualities of the stego-images of the proposed scheme
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Experimental results
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Experimental results
Sno=1 Sno=2 Sno=3
GoldHill 54.222dB 51.264dB 47.788dB
Lena 53.923db 49.122dB 47.404dB
1024 codebook
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Conclusion
A novel image hiding scheme based on vector quantization is proposed.
The proposed scheme is secure.
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Comments
用 VQ將 secret images壓縮,所以 secret images取出後會失真。
將 index table再壓縮,隱藏數量變少。