Feature Space Based Watermarking in Multi-Images

Xin Zhou

Outlines

Introduction

Feature Space Based Watermarking

Simulation Results

Conclusion

Introduction

Goal: Implement the watermarking in a set of images

or video based on eigen-decomposition or SVD (Singular Value Decomposition)

Introduction(2)

Where to embed bits? Spatial Domain: Directly process original values of the

host image according to the watermark Frequency Domain: Transfer the host image into

another domain and change the corresponding coefficients according to the watermark

Is it possible to embed bits in the feature domain?

Introduction(3)

Other’s Work Using SVD (Singular Value Decomposition) to embed

bits in one image Using ICA (Independent Component Analysis) to

detect the watermark

What I want to do Find a method to use eigen-decomposition or SVD to

embed watermark in multi-images or video It will be more robust to embed bits in each images More difficult for others to estimate the watermark

Feature Based Watermarking

Eigen-Decomposition and SVD

Embed one bit

Detection

Embed watermark in a set of images

Eigen-Decomposition and SVD

mxn matrix A, of rank r, can be expressed as the product:

A = U * S * VT

U is mxr term matrix S is rxr diagonal matrixV is rxn document matrixIf A is nxn matrix, r=n, we have

A *U= U * S

Embedding One Bit (1)

Assume the host image is a mxn matrixPerform the SVD to get S matrixEmbed one bit in the S matrix according to

where {si}: original coefficients{si’}: marked coefficients{b}: the bit to be embedded which is 0 or 1k : watermark strength, adjusted by the just-noticeable-

difference (JND) standard

'i is s k b

Embedding One Bit(2)

After Embedding:

A’ = U * S’ * VT

where S’ is the watermarked singular matrix

A’ is the corresponding watermarked image

Detection

Assume we get the watermarked image A’.

Perform eigen-decomposition or SVD to get the S’

Compare S and S’, we can get the watermark

'i is s

bk

Embedding in Multi-Images

Method I: Generate a pseudo random codebook Decide which bit should be embedded to which

image based on the codebook For a specific image, use the previous method to

embed bits

Method II: Use QIM-like method to decide which bit should

be embedded to which image.

Simulation Results (1)

Simulation Results (2)

Conclusion

Using eigen-decomposition or SVD to embed watermark into multi-images.

Implemented basic functions of the proposed method

Need to do more tests under various attacks