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Digital Watermark - Explanation


Digital Watermark  2020 Definition


Digital Watermark - Explanation Definition Explanation


A digital watermark is a kind of marker covertly embedded in anois tolerant signals such as an audio video or image data. It is typically used to identify ownership of the copyright of such signal watermarking. Is the process of hiding digital information in a carrier signal. The hidden information should but does not need to contain a relation to the carrier signal. Digital watermarks may be used to verify the authenticity or integrity of the carrier signal or to sell the identity of its owners. It is prominently used for tracing copyright infringements and for bank note authentication. Like traditional physical watermarks, digital watermarks are often only perceptible under certain conditions. That is, after using some algorithm. If a digital watermark distorts the carrier signal in a way that it becomes easily perceivable. It may be considered less effective depending on its purpose. 


Traditional watermarks may be applied to visible media like images or video, whereas in digital watermarking the signal may be audio pictures, video texts or 3D models. A signal may carry several different watermarks at the same time. Unlike metadata that is added to the carrier signal, a digital watermark does not change the size of the carrier signal. The needed properties of a digital watermark depend on the use case in which it is applied for marking media files with copyright information. A digital watermark has to be rather robust against modifications that can be applied to the carrier signal. Instead, if integrity has to be ensured, a fragile watermark would be applied. Both steganography and Digital Watermarking employs graphic techniques to embed data covertly in noisy signals. But whereas steganography aims for imperceptible A-T to human senses, Digital Watermarking tries to control their robustness as top priority. Since a digital copy of data is the same as the original digital watermarking is a passive protection tool, it just marks data but does not degraded or control access to the data.


 One application of digital watermarking is source tracking. A watermark is embedded into a digital signal at each point of distribution. If a copy of the work is found later than the watermark may be retrieved from the copy and the source of the distribution is known. This technique reportedly has been used to detect the source of illegally copied movies. The term digital watermark was coined by Andrew Jerko and Charles Osborne in December 1992, the first successful embedding and extraction of a steganography spread spectrum. Watermark was demonstrated in 1993 by Andrew Turkel, Charles Osborne and Gerard Renkin. Watermarks are identification marks produced during the paper making process. The first watermarks appeared in Italy during the 13th century, but their use rapidly spread across Europe. They were used as a means to identify the paper maker or the trade guild. They manufactured the paper the marks of and were created by a wire sewn on to the paper mould. Watermarks continued to be used today as manufacturers marks and to prevent forgery. The information to be embedded in a signal is called a digital watermark, although in some contexts the phrase digital watermark means the difference between the watermark signal and the cover signal. 


The signal where the watermark is to be embedded is called the host signal. A watermarking system is usually divided into three distinct steps embedding attack and detection in embedding, an algorithm accepts the host sent the data to be embedded and produces a watermarked signal. Then the watermarked digital signal is transmitted or stored, usually transmitted to another person if this person makes a modification. This is called an attack. While the modification may not be malicious. The term attack arises from copyright protection application, where third parties may attempt to remove the digital watermark through modification. There are many possible modifications. For example, lossy compression of the data in which resolution is diminished. Crafting an image or video or intentionally adding noise detection, often called extraction, is an algorithm which is applied to the attack signal to attempt to extract the watermark from it. If the signal was a. Modified during transmission, then the watermark still is present and it may be extracted in robust digital watermarking applications. The extraction algorithm should be able to produce the watermark correctly, even if the modifications were strong in fragile digital watermarking, the extraction algorithm should fail if any changes made to the signal.

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