This document provides an overview of digital watermarking. It defines digital watermarking as a technique that embeds a low-energy signal or watermark imperceptibly into digital content. The document discusses different types of watermarking including robust, fragile, visible, and invisible watermarking. It also outlines various digital watermarking techniques and applications for copyright protection, content authentication, and metadata tagging. The document concludes that digital watermarking is an effective technique for protecting digital content and preventing illegal copying.
2. Overview
Introduction
What is Watermarking?
What is Digital Watermarking?
Behind the Technology.
Importance
Types of Watermarking.
Digital Watermarking Techniques.
Features of Digital Watermarking.
Applications
Attacks to Digital Watermarking.
Conclusion.
3. Introduction
Advantages of Digital Data
Copy right problems with digital data
Encryption & Decryption
Problems with Encryption & Decryption
5. Watermark
“ Watermarking can be considered as a special
technique of steganography where one message is
embedded in another and the two messages are
related to each other in some way. “
Example :-
The presence of specific patterns in currency notes
which are visible only when the note is held to light is
a well known example for watermark.
What is Watermarking?
6. Example of a conventional
watermark
Courtesy of Blue Spike, Inc.
8. What is Digital Watermarking?
“ Digital watermarking is similar to watermarking
physical objects, except that the watermarking technique
is used for digital content instead of physical objects. “
Digital Watermark
9. Digital Watermark (Contn..)
In digital watermarking a low-energy signal is
imperceptibly embedded in another signal. The
low-energy signal is called watermark.
The main signal in which the watermark is
embedded is referred to as cover signal since it
covers the watermark.
An entity called watermark key used for
embedding and detecting watermark signal
Watermark key is private
10. Behind The Technology
Sending Side …
Watermark Embedding process
Water mark
Original message
Key
Water marked image
15. Robust & Fragile
Watermarking
Robust Watermarking:-Modification of
watermarked content will not affect watermark
Fragile Watermarking:-Watermark get
destroyed when watermarked content is
modified or tampered with
18. Public & Private
Watermarking
• Public Watermarking
Users of content are authorized to detect
watermark
• Private Watermarking
Users not authorized to detect watermark
21. Steganographic & Non-
Steganographic
Watermarking
Steganographic Watermarking
User unaware of the presence of a watermark
eg:-Used in finger printing applications
Non-Steganographic WM:-
User aware of the presence of a watermark.
e.g.:-User to detect piracy
22. Digital Watermarking
Techniques
LSB Watermarking
Color Separation Technique
Bit Stream Watermarking
Word Space Coding, Line Space Coding
&Character Coding
23. LSB Watermarking
Lower order bits of selected pixels in the
image are used to store watermarks
Replacing lower order bits of each pixel with
higher order bit of different image
24. Color Separation Technique
Watermark appears only in one of the color
bands
Used to watermark in still images
Can be extended to moving images
25. Bit Stream Watermarking
Used in audio watermarking
Data is directly inserted into compressed
audio files
26. Word Space Coding, Line Space
Coding &Character Coding
Used for watermarking in text documents
In word space coding, the spaces between
words are altered to embed watermark code. In
line space coding the space between the lines
are altered and in character coding some of
the characters are imperceptibly modified (i.e.,
made larger, serifs enhanced, etc).
29. Copy Protection
It limits the access to copyrighted material
and inhibit the copy process
30. Content Authentication
Robust watermarks are used in this area
Example:-A photographic information that may
be presented as evidence in court. Since digital
images can be easily manipulated, there is a
need to provide proof that an image has not
been altered.
33. Metadata Tagging
Watermarks convey object specific information
to users of the object.
Used to attach patient identification data to
medical images, or to highlight regions of
diagnostic significance.
35. Stirmark
It is tool developed to test the robustness of
image marking system
Stirmark is commonly produced by printers
and scanners
IBM researchers have recently announced a
technique that defeats the stir mark attack.
Detects and measures the geometric
distortions in images, and removes the
distortion to restore image geometry
37. Mosaic Attack
Use of a web crawler
Dividing into sub images with rendition
instructions
Browser will be rearranging the sub images to
appear as the original
Sub images will be sufficiently small that no
single image on its own will contain a
recognizable mark.
39. Conclusion
DRM systems and content management are important
for protection of rights of digital multimedia creations
that are distributed on the Internet. Digital
watermarking is an effective technique for embedding
rights information in digital multimedia data.
Digital watermark technology can be used in consumer
electronic devices like digital still camera, digital video
camera, DVD players, MP3 players, etc., for various
applications like providing controlled access,
preventing illegal replication and watermark
embedding
40. Conclusion (Contd..)
Digital information can easily be disseminated
and copied via global networks.
The future of digital watermarking relies on
setting standards and creating applications so
that creators of digital content can easily
implement it.