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digital_watermarking

VIEWS: 9 PAGES: 19

  • pg 1
									DIGITAL WATERMARKIG IN SPATIAL
            DOMAIN

Prepared By:

Prepared By :




                             1
              OUTLINE
•   Introduction
•   Methods
•   New Image Watermarking Algorithm
•   Experimental Results
•   Future Direction
•   Conclusion



                                       2
         INTRODUCTION
• Watermarking is a concept of
  embedding a special pattern,
  watermark, into a document
• Watermarking is a key process for the
  protection of copyright ownership of
  electronic data Watermark
                         W
                                        Watermarking
                   Host-Image I                        Watermarked
                                         Algorithm       Image Ì
                  Secret / public key
                           K


                                                                3
        INTRODUCTION
• An existing scheme for still image
  watermarking in spatial domain is studied.
• The features of the algorithm are:
  – The watermark to be embedded is a visually
    meaningful binary image;
  – More resistant to any attack;
  – retrieval of embedded watermark is easy;
  – the watermark is perceptually invisible;

                                                 4
        WHY DIGITAL
       WATERMARKING
• Cryptography ensures confidentiality,
  authenticity, and integrity
• It cannot help after decryption
• Digital Watermarking can help
  – Prove ownership
  – Identify a misappropriating person
  – Trace the marked document’s
    dissemination through the network

                                          5
HOW IT WORKS




               6
TECHNICAL REQUIRMENTS


              Capacity




 Robustness              Invisibility



                                        7
    METHODS FOR DIGITAL
      WATERMARKING

• Digital watermarking techniques can be
  divided into two broad categories:
• 1.Spatial domain methods .
• 2 Frequency domain methods.



                                           8
       SPATIAL DOMAIN
          METHODS
• The term spatial domain refers to the
  aggregate of pixels composing an
  image. Spatial domain methods are
  procedures that operate directly on
  these pixels. Spatial Domain processes
  will be denoted by the expression ,
                    g(x,y)= T[f(x,y)]


                                           9
ATTACKS ON WATERMAKING


•   Compression
•   Rescaling
•   Processing operation
•   Cropping
•   Multiple watermarks



                           10
THE PROPOSED MODEL




                     11
EMBEDDING WATERMARK




                      12
 WATERMARK DETECTION
• b=1 if Snew >So,
• b=0 Otherwise.




                       13
    EXPERIMENT RESULT
• The proposed algorithm was implemented
  using Matlab where the watermark is
  extracted after compression attack.
• Results




                                           14
            EVALUATION
•   A simple watermarking scheme
•   Invisibility
•   Resist to lossy compression
•   Watermark is invisible even though the
    picture in binary format.




                                             15
          APPLICATIONS
• Copyright defense
• Three types of watermark
          i) Private-key
          ii) Detection-key
          iii) Public-key


• Trace the route of the certain files during
  distribution

                                                16
     FUTURE DIRECTION
• Increase robustness against lossy
  compression
• Use better quad tree decomposition
  coding
• Change the way to insert key.
• Encode      the    watermark     before
  embedding.
• Extend the watermark techniques to
  wireless environment
                                            17
            CONCLUSION
• Video Watermarking is needed since
  copyright protection is essential
• Watermarking in spatial domain is different
  from frequency domain.
• Spatial domain watermarking model is
  proposed and implemented
• Watermark is embedded in MSB to
  increase the efficiency

                                                18
THANK YOU!!!!

                19

								
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