Digital Watermarking 1.0

Digital watermarking has been proposed as a viable solution to the need of copyright protection and authentication of multimedia data in a networked environment, since it makes possible to identify the author, owner, distributor or authorized consumer of a document. In this paper a new watermarking technique to add a code to digital images is presented: the method operates in the frequency domain
embedding a pseudo-random sequence of real numbers in a selected set of DCT coeficients. Watermark casting is performed by exploiting the masking characteristics of the Human Visual System, to ensure watermark invisibilily. The embedded sequence is extracted without resorting to the original image, so that the proposed technique represents a major improvement to methods relying on the comparison
between the watermarked and original images. Experimental results demonstrate that the watermark is robust to most of the signal processing techniques and geometric distortions.