Dual Image Watermarking

7/28/2019 Dual Image Watermarking

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DUAL IMAGE

WATERMARKINGPresented By-

Sachin Deshmukh.

9970406068

Guided By-


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INDEX

Introduction

SVD

Primary Watermarking

Secondary Watermarking

Applications

Advantages & Disadvantages

Conclusion

References


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INTRODUCTION

Watermark

What is Digital Watermarking? Dual Watermarking


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SINGULAR VALUE DECOMPOSITION:

(SVD)

The singular value decomposition (SVD) is

a factorization of a real or complex matrix, with

many useful applications in signal processing andstatistics.

It is a one type of transformation.


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CONTINUED

TVSUA

T

N

N

N

vvvuuu ,...,,

00

000

00

00

,...,,21

2

1

21

Assume that rank ofA is r.

Uand Vare Nx Northogonal matrices,Ux UT=I, Vx VT=I

S is an Nx Ndiagonal matrix,

1 2 r r+1 ==N=0


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PRIMARY WATERMARKING :

LL1 HL1

LH1 HH1

The frequency sub band LL1 is divided into

small blocks bk of size 4*4


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EMBEDDING ALGORITHM :

Input : Block bk, watermark w with co-ordinates (i,j)1. Let k=0

2. Perform SVD on the block bk

3. It will give the three matrices Uk, Dk and Vk.

1 0 0 0 1,2, 3, 4

Dk= 0 2 0 0 are the singular values of bk.

0 0 3 0 If w(i,j)==1, 4 = 2- 3.

0 0 0 4 This will give the watermarked Dk.

4.Perform inverse SVD and reconstruct the all blocks.

It will give the watermarked Wbk.5. k=k+1, go to step 2.

6. Combine all watermark blocks Wbk and we will get thewatermarked image I


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EXTRACTION ALGORITHM :

Input : Watermarked Block Wbk, co-ordinates (i,j)1. Let k=0

2. Perform SVD on the block Wbk

3. It will give the three matrices UWk, DWk and

VWk.w1 0 0 0 w1, w2, w3, w4

DWk= 0 w2 0 0 are singular

0 0 w3 0 values.

0 0 0 w44.EW(i,j)=1

5. k=k+1, go to step 2 until

all watermark bits are extracted.


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SECONDARY WATERMARKING

The watermarked image I is decomposed intofour sub bands.

The global mean g of sub band LL1is

calculated by taking the mean of all pixels in thesub band LL1.

LL1 HL1

LH1 HH1


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GENERATION OF OWNERS SHARE

Input: Low frequency sub band LL1 ,watermark

W and a key K2.

1. Compute the global mean g of sub band LL1.

2. Generate a list of two-dimensional random

number pair (m,n) using key K2.


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CONTINUED

3. For each pixel value in LL1at the random

location (m,n) and the global mean g from and

each watermark value W(i,j)at location (i,j)from,

generate the owners blocko.

4. Repeat the step 3 until all pixels

are processed.

5. The ownership share O is made

up of blocks of o.


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OWNERS SHARE :

Rule Comparison Between

LL1(m,n) and g

Watermark

W(i,j)

Owners block

o

1

2

LL1(m,n) g

LL1(m,n) g

0

1

3

4

LL1(m,n) g

LL1(m,n) g

0

1


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GENERATION OF IDENTIFIERS SHARE :

Input: Low frequency sub band LL1 of

controversial image and key K2.

1. Compute the global mean g of sub band LL1of the image.

2. Generate a list of two-dimensional random

number pair (m,n) using key K2.


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CONTINUED

3. For each pixel value in LL1at the random

location (m,n) and the global mean g and each

sub watermark value W(i,j) at location (i,j),

generate the master blockm.

4. Repeat the step 3 until all random locations are

being processed.


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IDENTIFIERSS SHARE :

Rule Comparison Between LL1(m,n)

and g

Owners block o

1 LL1(m,n) g

2 LL1(m,n) g


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APPLICATIONS :

1. Copyright Protection

2. Ownership Assertion

3. ID card security4. Military Applications

5. Medical Applications


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ADVANTAGES :

1. It is the robust watermarking scheme.

2. It is best against many attacks.

3. Low distortion


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REFERENCES :

1. www.ijetae.com (ISSN 2250-2459, Volume 2,

Issue 7, July 2012)

2. S. Voloshynovkiy, S. Pereira, T. Pun, J. Eggers

and J. Su, Attacks on digital watermarks, IEEEcommunications Magazine, vol.39, no. 9

3. I.J. Cox and M. Miller, Electronic watermarking:

Journal of Applied Signal Processing, vol. 2002,Issue 2.

4. http://www.petitcolas.net/fabien/watermarking


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Dual Image Watermarking