Attacking Visible Watermarking Schemes

Visible watermarking schemes are important intellectual property rights (IPR) protection mechanisms for digital images and videos that have to be released for certain purposes but illegal reproductions of them are prohibited. Visible watermarking techniques protect digital contents in a more active manner, which is quite different from the invisible watermarking techniques. Digital data embedded with visible watermarks will contain recognizable but unobtrusive copyright patterns, and the details of the host data should still exist. The embedded pattern of a useful visible watermarking scheme should be difficult or even impossible to be removed unless intensive and expensive human labors are involved. In this paper, we propose an attacking scheme against current visible image watermarking techniques. After manually selecting t,he watermarked areas, only few human interventions are required. For watermarks purely composed of thin patterns, basic image recovery techniques can completely remove the embedded patterns. For more general watermarks consisting of thick patterns, not only information in surrounding unmarked areas but also information within watermarked areas will be utilized to correctly recover the host image. Although the proposed scheme does not guarantee that the recovered images will be exactly identical to the unmarked originals, the structure of the embedded pattern will be seriously destroyed and a perceptually satisfying recovered image can be obtained. In other words, a general attacking scheme based on the contradictive requirements of current visible watermarking techniques is worked out. Thus, the robustness of current visible watermarking schemes for digital images is doubtful and needs to be improved.