24-05-2014, 11:36 AM
Digital Watermarking
Digital Watermarking.pdf (Size: 231.13 KB / Downloads: 93)
Abstract
Today’s world is digital world. Nowadays, in every
field there is enormous use of digital contents. Information
handled on INTERNET and MULTIMEDIA NETWORK SYSTEM
is in digital form. The copying of digital content without quality
loss is not so difficult .Due to this , there are more chances of
copying of such digital information. So , there is great need of
prohibiting such illegal copyright of digital media. Digital
watermarking (DWM) is the powerful solution to this problem.
Digital watermarking is nothing but the technology in which
there is embedding of various information in digital content
which we have to protect from illegal copying. This embedded
information to protect the data is embedded as watermark.
Beyond the copyright protection, Digital watermarking is
having some other applications as fingerprinting, owner
identification etc. Digital watermarks are of different types as
robust, fragile, visible and invisible. Application is depending
upon these watermarks classifications. There are some
requirements of digital watermarks as integrity, robustness
and complexity.
Introduction
he process of embedding information into another
object/signal is termed as digital watermarking. In
visible watermarking, the information is visible in
the picture or video. Typically, the information is text or a
logo which identifies the owner of the media. The image
on the right has a visible watermark. When a television
broadcaster adds its logo to the corner of transmitted
video, this is also a visible watermark. In invisible
watermarking, information is added as digital data to
audio, picture or video, but it cannot be perceived as
such (although it may be possible to detect that some
amount of information is hidden). The watermark may be
intended for widespread use and is thus made easy to
retrieve or it may be a form of Steganography, where a
party communicates a secret message embedded in
the digital signal. In either case, as in visible
watermarking, the objective is to attach ownership or
other descriptive information to the signal in a way that
is difficult to remove. It is also possible to use hidden
embedded information as a means of covert
communication between individual. The purpose of
embedding the information depends upon application
and need of user of digital media.
Properties and classification
a) Properties
For better activeness, watermark should be
perceptually invisible within host media, statistically
invisible to unauthorized removal, readily extracted by
owner of image, robust to accidental and intended
signal distortion like filtering compression, resampling,
retouching, crapping etc. For a digital watermark to be
effective for ownership, it must be robust, recoverable
from a document, should provide the original
information embedded reliably and also removed by
authorized users.
Conclusion
The large need of networked multimedia system
has created the need of “COPYRIGHT PROTECTION”. It
is very important to protect intellectual properties of
digital media. Internet playing an important role of digital
data transfer. Digital watermarking is the great solution
of the problem of how to protect copyright. Digital
watermarking is the solution for the protection of legal
rights of digital content owner and customer.
• Modifications of all DCT coefficients distort the
image drastically.
• Modification of low – frequency coefficients distorts
the image, Gives the hacker a clue about where the
watermark is embedded
Digital Watermarking.pdf (Size: 231.13 KB / Downloads: 93)
Abstract
Today’s world is digital world. Nowadays, in every
field there is enormous use of digital contents. Information
handled on INTERNET and MULTIMEDIA NETWORK SYSTEM
is in digital form. The copying of digital content without quality
loss is not so difficult .Due to this , there are more chances of
copying of such digital information. So , there is great need of
prohibiting such illegal copyright of digital media. Digital
watermarking (DWM) is the powerful solution to this problem.
Digital watermarking is nothing but the technology in which
there is embedding of various information in digital content
which we have to protect from illegal copying. This embedded
information to protect the data is embedded as watermark.
Beyond the copyright protection, Digital watermarking is
having some other applications as fingerprinting, owner
identification etc. Digital watermarks are of different types as
robust, fragile, visible and invisible. Application is depending
upon these watermarks classifications. There are some
requirements of digital watermarks as integrity, robustness
and complexity.
Introduction
he process of embedding information into another
object/signal is termed as digital watermarking. In
visible watermarking, the information is visible in
the picture or video. Typically, the information is text or a
logo which identifies the owner of the media. The image
on the right has a visible watermark. When a television
broadcaster adds its logo to the corner of transmitted
video, this is also a visible watermark. In invisible
watermarking, information is added as digital data to
audio, picture or video, but it cannot be perceived as
such (although it may be possible to detect that some
amount of information is hidden). The watermark may be
intended for widespread use and is thus made easy to
retrieve or it may be a form of Steganography, where a
party communicates a secret message embedded in
the digital signal. In either case, as in visible
watermarking, the objective is to attach ownership or
other descriptive information to the signal in a way that
is difficult to remove. It is also possible to use hidden
embedded information as a means of covert
communication between individual. The purpose of
embedding the information depends upon application
and need of user of digital media.
Properties and classification
a) Properties
For better activeness, watermark should be
perceptually invisible within host media, statistically
invisible to unauthorized removal, readily extracted by
owner of image, robust to accidental and intended
signal distortion like filtering compression, resampling,
retouching, crapping etc. For a digital watermark to be
effective for ownership, it must be robust, recoverable
from a document, should provide the original
information embedded reliably and also removed by
authorized users.
Conclusion
The large need of networked multimedia system
has created the need of “COPYRIGHT PROTECTION”. It
is very important to protect intellectual properties of
digital media. Internet playing an important role of digital
data transfer. Digital watermarking is the great solution
of the problem of how to protect copyright. Digital
watermarking is the solution for the protection of legal
rights of digital content owner and customer.
• Modifications of all DCT coefficients distort the
image drastically.
• Modification of low – frequency coefficients distorts
the image, Gives the hacker a clue about where the
watermark is embedded