Geometrically Invariant Image Watermarking in the DWT Domain.

Watermark resistance to both geometric attacks and lossy compressions is a fundamental issue in the image watermarking community. In this paper, we propose a DWT (Discrete Wavelet Transform) based watermarking scheme for such a challenging problem. Watermark resistance to geometric deformations is achieved by using the invariance of the histogram shape. In both theoretical analysis and experimental way, we show that the invariance can be extended to the DWT domain thanks to the time-frequency localization property of DWT. Consequently, we achieve the goal to embed a geometrically invariant watermark into the low-frequency sub-band of DWT in such a way that the watermark is not only invariant to various geometric transforms, but also robust to common image processing operations. Extensive simulation results demonstrate the superiority of the proposed watermark strategy due to the use of the histogram shape invariance combined with the DWT technique. [ABSTRACT FROM AUTHOR]