The growth of computer networks has boosted the growth of the information technology sector to a greater extent. At the same time care is taken to prevent the unauthorized use of the images commercially and also the observer is encouraged to patronize the institution that owns the material. To satisfy both these needs simultaneously the owner needs to use visible watermarking. Visible watermarking is a type of digital watermarking used for protection of publicly available images. In this paper, we describe a visible watermarking scheme that is applied into the host image in the DCT domain. A mathematical model has been developed. We have also proposed a modification of the algorithm to make the watermark more robust. Thus, digital watermarking can be considered to be a supplementary technique to well established encryption schemes.

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Digital Watermarking dct