Wavelet Based Data Hiding of DEM in the Context of Realtime 3D Visualization

1
Wavelet Based Data Hiding of DEM in the Context
of Real-time 3D Visualization

• Presented By
• Khizar Hayat

2
The Team

• Student
• Khizar Hayat
• Supervisor
• William Puech (LIRMM/ROB/ICAR)
• Co-supervisors
• Marc Chaumont (LIRMM/ROB/ICAR)
• Gilles Gesquiere (LSIS - University of Marseille)
• Concerned PhD student
• Philippe Amat

3
The Problem

• How to achieve optimal real-time 3D visualization
  in a client server environment in a scalable and
  synchronized way compatible with the clients
  computing resources and requirements?

100 Data
A fraction of Data
4
The Proposed Solution

• Our Approach
• Discrete Wavelet Transform (DWT) of JPEG2000
• Data Hiding LSB based embedding
• Advantages
• Compression to reduce the amount of data
• Scalability - different levels of detail for
  various
• Platforms
• Users
• contexts
• Synchronization reduce the number of files

5
Essential Concepts

• JPEG2000
• Data Hiding/ Steganography
• 3D Visualization

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JPEG2000


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DWT in JPEG2000
Let Sj 1D input signal (pixel row or pixel
column) Lk lowpass subband signal Hk
highpass subband signal Where 1 j n and 1
k n/2 Then

• Lossless (Daubechies 5/3)

Lossy (Daubechies 9/7)
Where a - 1.586134 b - 0.052980 c
0.882911 d 0.443506 With ß and ß, the
scaling parameters ß 0.812893 ß 1/ ß
S2n1 the first stage lifting outcomes S2n
the second stage lifting outcomes
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LSB Based Data Hiding

• Embed the message bits directly into the
  least-significant bit plane of the cover image in
  a deterministic sequence, e.g. PRNG
• Advantages
• Easy to understand and comprehend ?popular
• High perceptual transparency
• Low degradation in the image quality
• High Hiding Capacity
• Disadvantages
• Low robustness to malicious attacks
• Vulnerable to accidental or environmental noise

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3D Visualization

• Three files are necessary
• Texture
• Altitude DEM ? Fig. a
• (50m by IGN France)
• Geo-referential coordinates (longitude /
  latitude)
• Two steps for visualization
• Triangulation (Fig. b)
• Aerial Photograph draped onto the triangles for
  3D visualization (Fig. c)

(a)
(b)
(c)
10
The Proposed Method
11
The Proposed Method

• RGB to YCrCb
• Texture.ppm
• Wavelet Transformation
• Lossy DWT of the YCrCb of Texture
• Lossless DWT of altitude (DEM)
• Insertion
• Trans DEM Trans Y plane of texture
• Correspondence
• Same level
• Factor of insertion (E)
• E m²/ N² (coefficients/ pixel)
• Block size 1/E ? 2 bytes per 32x32 block in our
  case
• LSB based Insertion with running a PRNG for pixel
  allocation
• Final Interleaved Image

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Results
Altitude Image (64x64 coefficients) 1 coefficient
16 bits
Texture Image (2048x2048 pixels) 1 Pixel 24 bits
Texture Image (A part magnified)
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Level 1 Transformation
Texture (2048x2048 pixels)
Altitude (64x64 coefficients)
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Level 3 Transformation
Texture (2048x2048 pixels)
Altitude (64x64 coefficients)
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Observations

Where
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Reconstruction from the Image of Approximation at
Level 3
Altitude Image (64x64 coefficients) 1 coefficient
16 bits
Texture Image (2048x2048 pixels) 1 Pixel 24 bits
Texture Image (A part magnified)
ATTENTION Only 1.6 of the initial data utilized
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Results
Altitude Image (64x64 coefficients) 1 coefficient
16 bits
Texture Image (2048x2048 pixels) 1 Pixel 24 bits
Texture Image (A part magnified)
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3D visualization of the Altitude from the Image
of Approximaton
Level 1
Level 0 - all the information
Level 2
Level 3
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3D navigation of the Constructed Images
All the data
Level 3 lowest suband data
ATTENTION Only 1.6 of the initial data utilized
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Conclusion

• Encouraging Results in the following contexts
• Compression
• Scalability and portability
• Synchronization
• Future Perspective
• Other aspects of JPEG2000
• Standard Software, e.g. OpenJPEG
• Geometric Wavelets
• Non uniform grid to decrease the number of
  triangles
• Exploration of Chrominance planes

21
Research Papers

• Papers expected to be published
• K. Hayat, M. Chaumont, G. Gesquiere and W. Puech.
  Visualisation 3D Temps-Réel à Distance de MNT par
  Insertion de Données Cachées Basée Ondelettes. In
  CORESA06, Caen, France, Nov. 2006. (Submitted in
  May 2006).
• K. Hayat, W. Puech, G. Gesquiere and M. Chaumont.
  Wavelet Based Data Hiding of DEM In the Context
  of Real-time 3D Visualization. In IST and SPIE
  07 - Visualization and Data Analysis 2007
  (EI108), San Jose, California, USA (to be
  submitted before 17 July 2006).

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References

• A. Martin, G. Gesquiere, W. Puech and S. Thon.
  Real Time 3D Visualisation of DEM Combined with a
  Robust DCT Based Data-Hiding Method. In
  Electronic Imaging, Visualization and Data
  Analysis, SPIE, IST, San Jose, CA, USA, volume
  6060, pages 60600G160600G8, Jan 2006.
• W. Sweldens. The Lifting Scheme a New Philosophy
  in Biorthogonal Wavelet Constructions. In
  Electronic Imaging, Wavelet Applications in
  Signal and Image Processing, SPIE, IST, San
  Diego, CA, USA, volume 2569, pages 6879, Sep.
  1995.
• I. Daubechies and W. Sweldens. Factoring Wavelet
  Transforms into Lifting Steps. Fourier Anal.
  Appl., 4(3), 1998.
• ISO/IEC 14492-1 Lossy/lossless coding of
  bi-level images, 2000.
• R. Raffin S. Thon and G. Gesquiere. Visualisation
  3D de Feux de Forêts sur des Modèles Numériques
  de Terrain de lIGN. In Rencontre GEO-RISQUE 2006
  La cartographie des risques naturels,
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• P. Meerwald and A. Uhl. A Survey of
  Wavelet-Domain Watermarking Algorithms (2001).
  Electronic Imaging, Security and Watermarking of
  Multimedia Contents, SPIE, IST, San Jose, CA,
  USA, Jan 2001.
• A. Piva, F. Bartolini and R. Caldelli. Self
  Recovery Authentication of Images in the DWT
  Domain. In International Journal of Image and
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• J. Li. Image Compression - The Mechanics of the
  JPEG2000. Microsoft Research, Signal Processing
  2002. (Available from http//research.microsoft.c
  om/jinl/paper_2002/msri_jpeg.htm).
• M.D. Adams. The JPEG-2000 Still Image Compression
  Standard (Last Revised 2005-12-03). ISO/IEC JTC
  1/SC 29/WG 1 (N 2412) (Available from
  www.ece.uvic.ca/mdadams)

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Thank You

• Questions ?