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PSYCHOVISUAL ROTATION-BASED

DPTC WATERMARKING SCHEME

Author : Marc CHAUMONT (LIRMM)

Speaker : Dalila GOUDIA (PhD Student - LIRMM)

The 17thEuropean Signal Processing Conference (EUSIPCO’2009), August 24-28, 2009, Glasgow, Scotland.

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OUTLINE

Few words about high rate watermarking schemes

The Rotation-Based Dirty Paper Trellis Code Algorithm: RB-DPTC

How to add a psycho-visual space ?

Experimental evaluations

Conclusion

Author: M. CHAUMONT, Speaker: D. GOUDIA

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F EW WORDS ABOUT HIGH RATE WATERMARKING SCHEMES

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HIGH RATE WATERMARKING SCHEMES

Quantized-based:

DC-QIM, SCS, RDM, Perceptual-QIM…

Trellis-based:

DPTC

Mix of Quantized-based and Trellis-based:

T-TCQ

payload  1 bit embedded for 64 pixels

(image 256×256  1024 bits embedded)

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Author: M. CHAUMONT, Speaker: D. GOUDIA

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T HE R OTATION -B ASED D IRTY

P APER T RELLIS C ODE

A LGORITHM : RB-DPTC

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RB-DPTC WATERMARKING SCHEME [1]

- EMBEDDING SPACE -

Author: M. CHAUMONT, Speaker: D. GOUDIA [1] M. Chaumont, « A Novel Embedding Technique For Dirty Paper Trellis Watermarking”,

in submission.

x : host signal

w : watermark signal

y : watermarked signal

: carriers

(normalized bipolar pseudorandom sequences)

vx : host vector = secret space

vw : watermark vector = (watermark in the secret space)

{u

i

}

Ni=1sec

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H OW TO ADD A PSYCHO - VISUAL SPACE ?

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RB-DPTC

WATERMARKING SCHEME [1]

Author: M. CHAUMONT, Speaker: D. GOUDIA

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[1] M. Chaumont, « A Novel Embedding Technique For Dirty Paper Trellis Watermarking”, in submission.

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P SYCHOVISUAL RB-DPTC

WATERMARKING SCHEME

Author: M. CHAUMONT, Speaker: D. GOUDIA + correcting code

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P SYCHOVISUAL RB-DPTC

WATERMARKING SCHEME

Author: M. CHAUMONT, Speaker: D. GOUDIA + correcting code

x

psy

: psychovisual space

Shaping of the watermark:

i[1,N

wlt

], w[i] = w

psy

[i] × α[i]

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Construction:

1. high pass filtering ( )

2. DWT and filling of vector 

3. α = absolute coefficients from  scaled

between [1, αmax]

E XAMPLE OF PSYCHOVISUAL MASKS

PW-M [3]:

(i,j): position in subband

l: resolution level

  {a,h,v,d} :orientation

: noise sensitivity

: local brightness

: local texture activity

α scaled between [1, α

max

] Rudimentary Pixel-Wise Mask (PW-M)

[3] Gui Xie and Hong Shen, “Toward Improved Wavelet-Based Watermarking Using The Pixel-Wise Masking Model,”

ICIP’2005, 2005, vol. 1, pp. 689–692.

Author: M. CHAUMONT, Speaker: D. GOUDIA

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12

Barbara crop to 512×512 Wavelet decomposition

Rudimentary mask Xie and Shen mask

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C ORRECTING CODE

Add of a convolution correcting code 2-memory, 1/2-rate

Encoding with the state machine

Decoding with Viterbi algorithm

The message is encoded before embedding

Author: M. CHAUMONT, Speaker: D. GOUDIA

The use of a psychovisual mask may lead to a less robust scheme

state-machine

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E XPERIMENTAL EVALUATIONS

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E VALUATION PROTOCOL

100 images 256×256

Payload = 1 bit (message) for 64 pixels

1024 bits embedded for RB-DPTC.

2048 bits embedded for new algorithms.

Trellis : 128 states, 128 arcs by state

Outputs arc labels : Gaussian distribution

number of labels by output arc: 12 (RB-DPTC) or 10.

Author: M. CHAUMONT, Speaker: D. GOUDIA

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A LGORITHMS

3 Algorithms are competing (fix SSIM = 98%):

RB-DPTC (no psychovisual mask, no correcting code)

PR-RB-DPTC (rudimentary mask + correcting code)

PXS-RB-DPTC (Xie and Shen mask + correcting code)

4 attacks:

Gaussian noise,

Gaussian filtering,

Valumetric scaling,

Jpeg attack.

Author: M. CHAUMONT, Speaker: D. GOUDIA

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A TTACKS (1) – F IXED SSIM = 98%

Gaussian noise attack Gaussian Filtering attack

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Author: M. CHAUMONT, Speaker: D. GOUDIA

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A TTACKS (2) – F IXED SSIM = 98%

Valumetric scaling attack Jpeg attack

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Author: M. CHAUMONT, Speaker: D. GOUDIA

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C ONCLUSION & DISCUSSION

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C ONCLUSION & D ISCUSSION

Integration of a psychovisual mask inside RB-DPTC

10% BER saving (filtering & valumetric attack) for low power attacks

OPEN ISSUES:

Sensitivity to Jpeg attack

Sensitivity to Westfeld [4] regression-based attack

Relation between SSIM and penetration angle

Construction of a robust psychovisual mask

[4] Andreas Westfeld, « A Regression-Based Restoration Technique for Automated Watermark Removal », Multimedia & Security ACM Workshop MM&Sec2008, Oxford, United Kingdom, Sept.2008.

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PSYCHOVISUAL ROTATION-BASED

DPTC WATERMARKING SCHEME

Author : Marc CHAUMONT (LIRMM)

Speaker : Dalila GOUDIA (PhD Student - LIRMM)

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A NNEX

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RB-DPTC WATERMARKING SCHEME

- EMBEDDING SPACE -

Author: M. CHAUMONT, Speaker: D. GOUDIA

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RB-DPTC WATERMARKING SCHEME

- INFORMED CODING & EMBEDDING -

Author: M. CHAUMONT, Speaker: D. GOUDIA

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RB-DPTC WATERMARKING SCHEME

- INFORMED CODING & EMBEDDING -

Informed coding:

identical to [2] (Trellis + Viterbi)

Input = (v

x

and message), Output = codeword c*

Informed embedding:

rotate v

x

in the “Miller Cox Bloom plane”

and penetrate inside the Voronoï region

v

w

= v

y

- v

x

[2] M. L. Miller, G. J. Do¨err, and I. J. Cox, “Applying Informed Coding and Informed Embedding to Design a Robust, High Capacity Watermark,” IEEE Transactions on Image Processing, vol. 13, no. 6, pp. 792–807, 2004.

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