A DWT domain visible watermarking techniques for digital images

The growth of computer networks has boosted the growth of the information technology sector to a greater extent. There is a trend to move from conventional libraries to digital libraries. Digital data can easily be used in an illegal way-being copied, modified and distributed again. Copy right protection, intellectual and material right protection for authors, owners, buyers and distributors and the authenticity of content are crucial factors in solving an urgent and real problem. In such scenario digital watermarking techniques has grown up as a valid solution. Watermarking community has focused on developing and introducing new techniques for watermark embedding and detection. Analysis of these techniques leads to methods for attack and development of countermeasures which then used to discover faults and limitations in applications, encouraging the development of better one. In this paper, we have given the overview of watermarking techniques and proposed a visible watermarking algorithm for copy write protection of digital images based on DWT (discrete Wavelet Transform) domain. Using DWT is motivated by good time frequency features and well matching with human visual system directives. We have also implemented it in tool MATLAB 7.x and given the code in this paper.