Invisible Watermark

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The invisible-robust watermark is embedded in such a way that alternations made to the pixel value are perceptually not noticed and it can be recovered only with appropriate decoding mechanism. The invisible-fragile watermark is embedded in such a way that any manipulation or modification of the image would alter or destroy the watermark. Figure 1.3: Example of Visible Watermark and Invisible Watermark Dual watermark is a combination of a visible and an invisible watermark. From application- point-of view digital watermark could be as below: • source based or • destination based. Source-based watermark are desirable for ownership identification or authentication where a unique watermark identifying the owner is introduced…show more content…
These digital files can be pictures, music, videos and other documents. The internet became user friendly with the introduction of the first widely used web browser in November 1993. The internet is an excellent distribution system for digital media because it is inexpensive and allows convenient downloading and sharing between individuals and organizations. Therefore, copying and modifying these files and documents have become very popular. The illegal copying of some types of media has been a subject of concern for many years. As a result, an urgent solution for copyright protection and authentication is needed. Digital watermarking is an effective solution to protect intellectual properties and copyrights by hiding information such as logos, signatures or text into multimedia data such as images, videos, or audio files. In the past, using analogue devices posed a lower risk than with digital media; copying an analogue file allows results in a degradation of the quality. However, with digital media recording devices, songs and movies can be produced with no degradation whatsoever in quality, since the data are a stream of 1’s and…show more content…
Therefore there is still a need for further protection of content, even after it is decrypted. Watermarking is a promising technology that can be used to full-fill the owner’s copyright protection. In digital watermarking, the information is hided inside the contents. Digital watermarking can survive different kinds of attacks, include compression, digital to analogue conversion, and file format changes. Watermarking has been considered for many copy prevention and copyright protection applications. In copy prevention, the watermark may be used to inform software or hardware devices that copying should be restricted. In copyright protection applications, the watermark may be used to identify the copyright holder and ensure proper payment of royalties. Although copy prevention and copyright protection have been major driving forces behind research in the watermarking field, there are a number of other applications for which watermarking has been used or suggested. These include broadcast monitoring, transaction tracking, and authentication. Other applications that require still image watermarking include medical images, satellite images, and image captured by mobile phone

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