An object-based non-blind watermarking that is robust to non-linear geometrical distortion attacks

This paper presents an object-based non-blind watermarking technique that is robust to non-linear geometrical distortion attacks. This has been one of the most challenging problems for copyright protection of digital content because it is difficult to estimate the distortion parameters for the embedded blocks. In our proposed scheme, the locations used to embed the watermark information are memorized and detected robustly by using relative coordinates with respect to the scale-invariant feature transform (SIFT) feature points. Experimental results with 64-bit watermark embedding demonstrated that the watermark detection performance was improved from 57% to 82% on average, even after nonlinear geometrical attacks such as waving, imploding, swirling, and seam carving.