DIGITAL WATERMARKING

Presented by: M.DIVYASRI Roll No:13701A0518

ContentsIntroductionHistoryTypes of watermarkAttributes associated with watermarking Techniques ApplicationsAdvantagesDisadvantagesConclusionReferences

IntroductionA digital watermark is a message which is embedded

into digital content (video, images or text) that can be detected or extracted later.

Digital Watermarking describes methods and technologies that hide information.

Image Video Audio

General Watermarking

Procedure

History More than 700 years ago, watermarks were used in

Italy to indicate the paper brand and the mill that produced it.

The term watermark was introduced near the end of the 18th century. It was probably given because the marks resemble the effects of water on paper.

In 1988, Komatsu and Tominaga appear to be the first to use the term “digital watermarking”.

Types of Watermark

VisibleInvisiblePublicFragile

Visible watermarkVisible watermark is a translucent overlaid

into an image and is visible to the viewer. Visible watermarking is used to indicate ownership and for copyright protection.

Original image Watermarked image

Invisible WatermarkAn invisible watermarked image appears very

similar to the original. The existence of an invisible watermark can only be determined using an appropriate watermark extraction or detection algorithm.

Original image watermarked image

Public WatermarkPublic watermark such a watermark

can be read or retrieved by anyone using the specialized algorithm.

Fragile WatermarkFragile watermarks are also

known as tamperproof watermarks. Such watermarks are destroyed by data manipulation

Attributes Associated With Watermarking

Imperceptibility Robustness Security Complexity Verification

Watermarking Techniques

Watermarking for text Word space coding Line shift coding

Watermarking Techniques…

Watermarking for text Feature coding

Watermarking Techniques… watermarking for images

spatial domain watermarking Frequency domain watermarking

AttacksRobustness attacks :Which are intended to remove the

watermark such as… JPEG compression, cropping, etc.

Presentation Attacks :Under watermark detection failure they come into play. Geometric transformation, rotation, scaling, translation, change aspect ratio, affine transformation etc.

Counterfeiting attacks :Rendering the original image, generate fake original.

Attacks on watermarked image

Detection of watermarksIt needs to be emphasized that a watermark can be

defeated in two ways – one, by removing the watermark from the original data and two, by proving it to be unreliable i.e. identifying a watermark when there is none.

ApplicationsCopy prevention or control In the field of data security

Applications………Tampering with images

Embedded watermark is easy Higher level of security Digital Watermarking is non-restrictive

only misuse is detectable and traceable.

Implementation on pc platform is possible Uniquely identifies author

Advantages

Disadvantages Visible watermark can be easily removed. Some watermarks vanish if some one manipulates

the image in a program like photoshop. Resizing , compression and converting images from

one file to another may add noise to an image. Owners can erase the mark

Conclusion The large need of networked multimedia system has

created the need of copy right protection .so, it is very important to protect intellectual properties of digital media . For this DIGITAL WATERMARKING is the great solution for the protection of legal rights of digital content.

Referenceswww.ieeexplore.ieee.orgwww.watermarkingworld.comwww.wikipedia.com

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