The so-called
digital watermarks and
digital watermarking are designed to add some digital information to the multimedia data, such as images (
digital watermarks images), voice (digital watermarks audio), and video signal and so on. It aims to distinguish the authority of documents, protect copyright functions and some other functions. Digital
image watermarking usually embeds visible or invisible watermarks in the main document, without affecting the appearance and integrity of original document.
Digital watermarks can embed some information that can protect copyright or track infringing behaviors in the protected digital data(such as images, video, audio, etc.) .The embedded information can be the author's serial number, company logo, meaningful text and so on .
In general, a
digital watermarks should have the following basic features:
(1) can be proved:
digital watermark should be able to provide complete and reliable evidence to the ownership of protected information products. Digital watermarks can identify the embedded relevant information (such as number of registered users, product logo or meaningful text, etc.) of the owners, and can extract the information when required. digital watermarks can distinguish whether the objects are protected and be able to monitor the protected data’s transmission, the authority and control of illegal copies. In fact this is the fundamental driving force developing digital watermarks technology, our watermarks software just directly designed for this purpose.
(2) can not be resumed: For a large number of digital pictures that digital watermarks techniques have dealt with, the digital watermarking on these pictures can not removed by any methods. The information products’ original appearance can not be restored. For example, if you digital watermarked a picture, then the logo on it can not be removed.
(3) permanence: The permanence problem is extremely important in terms of digital watermarks. In short, it refers to digital watermarks should bear a large number of different physical and geometric distortion, including the intentional (such as malicious attacks) or unintentionally (such as image compression, scanning and copying, noise pollution, changes in size and so on) . After these operations, the digital watermarks still can be identified clearly. Digital images will be effectively protected, even if when there is the physical distortion, it still able to provide enough evidence of copyright.
