Applications of digital watermarking

Broadcast monitoring:
Watermarks are used in broadcast monitoring by inserting watermarks in the message that is to be transmitted. This is done before signal (audio or video) is broadcasted

Contractual watermarks:
These types of watermarks are also called fingerprints. One of the applications of these is
In the distribution of daily film copies. Many people and organizations might be involved
In the distribution of a film copies. Many people and organizations might be involved in the distribution of a film. In this process, there could be possibilities of leakage of leakage
Secret communication:
This was one of the earliest applications of watermarking technique. It is a process of transmitted secret messages in concealed form. Specially designed programs are there to accomplish these tasks.
Copy control:
Many watermarks do not actually prevent the coping of content into which they are embedded, but serve as identification marks of the genuine owner of it. But using certain mechanisms that detect the watermarks and inhibit the copying of the information, it is possible to preserve the integrity of the information.

Need of Watermarking.

In these days it is very hard to protect some information or image or video or any other thing from theft. Though we used many techniques to protect out data ,someone steals it and deletes that technique and frees it from our identification.So it is very hard to protect our data.
To overcome this problem we have a solution i.e is called as watermarking.In watermarking we insert some bits of data into our data or image or audio or video.That bits most probably contain author and copyright information of that file. Watermarking is also called data embedding and information hiding.

conclusion

Digital watermarking is an outstanding technology that can serve a wide range of applications in various media types. But, the employment of schemes depends upon the requirements that may vary widely. A sound knowledge of communication techniques and signal processing methods is essential for efficient development of watermarking techniques. Besides this the attacks that the signal is expected to endure the assessment of the amount of distortion that the signal suffered which in turn determine the efficacy of the system and the effective cost involved need to be taken into consideration while designing watermarking technique for particular application. Thus the standards for all the applications don’t remain alike.

Types of Watermarking

Digital audio watermarking:
Herein, the watermark i.e. the digital audio watermark consists of the information pertaining not to the only to the creator of the audio information that could be any one of several forms of song, music etc., but also to the authenticated user of the audio information. This allows that particular information to be used by only the authorized user and no one else. The watermark can also be used for secondary applications other than authentication.e.g. Providing information about the song, album, style of tunes, etc. This watermark is useful in voice conferencing halls to indicate the person who is speaking at the moment .
Digital video watermarking:
A watermark inserted in a video signal can be used for DVD copy protection. First of all; the watermark should satisfy the requirements of strength and imperceptibility. Besides this, it can be bestowed on to convey the information to restrict copying in many ways such as copy never i.e. The DVD is copy protected, copy no more i.e. it is possible to copy a finite number of times, copy liberally i.e. it can be copied any number of times, copy only once. The design depends upon the content in the DVD. A general process of digital video watermarking consists of inserting a group of bits along with the video frame to be transmitted.
Image watermarking:
For watermarking a still image, the watermark is directly inserted on the picture of information itself such as colour, brightness, and luminescence etc. the watermark may be inserted directly onto the pixels.
Text watermarking:
Text watermarking is the process of inserting watermark into the text for preserving the creator’s identity. This is especially applicable to such valuable texts such as poetry. An earlier form of watermarking the texts was accomplished by inserting spaces in specific parts of the text. The disadvantage associated with this form of watermarking was that it was quite is to remove the watermark

WATERMARK DECODING

The method of deciding about whether a signal received contains a watermark or not is ‘detection’. But, identification is the actual process of decoding the unique watermark from a finite number of possible choices. The two kinds of errors could occur at the detection. The first one is detection of watermark in the received signal when it really does not exist. The second one is quite opposite to this. Herein, the watermark, which inherently exists in the received data, is not detected. Synchronization failure between watermark embedding and detection process could disable the entire communication process. This could result in attacks on the signal

Watermarking

In the wake of increasing copyright misuses, several new technologies are developed to preserve the authentication of information. Digital water marking is one of them. It is a technique that allows us to add hidden copyright notices, verification messages or any other useful information to the original signal. The hidden message can be a group of bits that describe something about the signal or about the genuine author of the signal.
WATERMARK INSERTION:
Mid frequency components are chosen for embedding the watermark in a simple way, owing to the shortcomings with the low frequency components and high frequency components. The difficulty with the low frequency components is that they are highly susceptible to distortion. The high frequency components do not bear much of information reliably, since their removal from the actual signal does not affect the signal’s quality too much.