Introduction :-
:-
In recent years, the distribution of works of art, including pictures, music, video and textual documents, has become easier. With the widespread and increasing use of the Internet, digital forms of these media (still images, audio, video, text) are easily accessible. This is clearly advantageous, in that it is easier to market and sell one's works of art. However, this same property threatens copyright protection. Digital documents are easy to copy and distribute, allowing for pirating. There are a number of methods for protecting ownership. One of these is known as digital watermarking.
Digital
watermarking is the process of inserting a digital signal or pattern
(indicative of the owner of the content) into digital content. The signal,
known as a watermark, can be used later to identify the owner of the work, to
authenticate the content, and to trace illegal copies of the work. Watermarks
of varying degrees of obtrusiveness are added to presentation media as a
guarantee of authenticity, quality, ownership, and source.
Abstract
Digital
watermarking is an extension of steganography, is a promising solution for
content copyright protection in the global network. It imposes extra robustness
on embedded
information. Digital watermarking is the science of embedding copyright
information in the original files. The information embedded is called
watermarks.
Digital Watermark
Types And Terms
Watermarks can be
visible or invisible:
a. Visible watermarks are designed to be
easily perceived by a viewer (or listener). They clearly identify the owner of
the digital data, but should not detract from the content of the data.
b. Invisible watermarks are designed to be
imperceptible under normal viewing (or listening) conditions; more of the
current research focuses on this type of watermark than the visible type.
A further
classification of watermarks is into fragile, semi-fragile or robust:
a. A fragile watermark is embedded in digital
data to for the purpose of detecting any changes that have been made to the
content of the data. They achieve this because they are distorted, or
"broken", easily. Fragile watermarks are applicable in image
authentication systems.
Purposes Of Digital Watermarks
1. They aim to mark digital data permanently
and unalterably, so that the source as well as the intended recipient of the
digital work is known. Copyright owners can incorporate identifying information
into their work.
2. With a tracking service, owners are able to
find illegal copies of their work on the Internet.
3. Watermarks can be used to identify any
changes that have been made to the watermarked data.
The Digital
Watermark
Digital
watermarking is a technology for embedding various types of information in
digital content. In general, information for protecting copyrights and proving
the validity of data is embedded as a watermark.
A
digital watermark is a digital signal or pattern inserted into digital content.
The digital content could be a still image, an audio clip, a video clip, a text
document, or some form of digital data that the creator or owner would like to
protect. The main purpose of the watermark is to identify who the owner of the
digital data is, but it can also identify the intended recipient.
Why
do we need to embed such information in digital content using digital watermark
technology? The Internet boom is one of the reasons. It has become easy to
connect to the Internet
from home computers and obtain or provide various information using the World
Wide Web (WWW).
All
the information handled on the Internet is provided as digital content. Such
digital content can be easily copied in a way that makes the new file
indistinguishable from the original.
Then the content can be reproduced in large quantities.
Authentication
Authentication
identifies if content has been altered or falsified. For example digital
watermarking can verify authenticity and identify counterfeiting as a second
layer of security for encrypted content. The presence of digital watermark
and/or continuity of watermark can help ensure that the content has not been
altered.
Conclusion
Digital watermarks
have been used in the last few years to protect the ownership of digital data.
Various techniques developed make use of the human audio-visual system.
Legitimate business and webmasters have nothing to fear from copyright law or
new form of on-line enforcement technology found in digital watermarks and
tracking services.
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