Digital watermark technology plays an important role in the field of information security. A novel image watermark scheme based on Contourlet transform and human visual system is proposed. The original carrier image w...
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Digital watermark technology plays an important role in the field of information security. A novel image watermark scheme based on Contourlet transform and human visual system is proposed. The original carrier image was executed in Contourlet transform and four various directions of the second level subband was indicated, afterwards, the scrambled digital watermark is embedded in them. The experimental results show that the proposed watermark algorithm is efficient and simple. The embedded watermark host images are not apparent distortion and the extracted watermark is easily discernible and accurate. The algorithm can resist all kinds of geometrical attacks and meet requirement of imperceptibility and robustness
Recently, as the fast development of the computer network communication technology, it's more and more convenient for the digital information storage and transmission. Therefore, more and more attention is focused...
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ISBN:
(纸本)9780769535210
Recently, as the fast development of the computer network communication technology, it's more and more convenient for the digital information storage and transmission. Therefore, more and more attention is focused on the copyright protection of digital information. An algorithm that gray image as watermark is embedded in original color-image is introduced. This algorithm thinks over both unobtrusiveness and robustness, and the size of image is unlimited. So it has strongly practical significance.
Spread-spectrum (SS) watermarking has been one of the oldest methodologies for hiding data in multimedia signals. Recently, it has been demonstrated that simple block repetition codes provide strong robustness of such...
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ISBN:
(纸本)0780374029
Spread-spectrum (SS) watermarking has been one of the oldest methodologies for hiding data in multimedia signals. Recently, it has been demonstrated that simple block repetition codes provide strong robustness of such watermarks to noise addition and limited arbitrary geometric transformations. In order to further investigate the security of such watermarks, we explore in this paper their robustness with respect to watermark estimation attacks. In such attacks, the adversary has knowledge of the watermark algorithm, except the secret keys. We present a modification of the traditional SS watermark detector that forces the adversary to increase the amount of noise to be proportional to the signal amplitude, in order to remove an SS watermark.
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