hybrid approach to digital image watermarking using informed coding, informed embedding and spread spectrum
The growth and popularity of the Internet has led to the data storage of multimedia data (audio, image and video) in digital form. The digitization form of multimedia data can be copied easily and then distributed again without the loss of fidelity. This leads to wide interest in multimedia security and multimedia copyright protection. Digital watermarking appears today as an efficient mean of securing and protecting multimedia data. It embeds a data called watermark into multimedia data such that watermark can be detected or extracted later to make an assertion about the multimedia data. In this report, we proposed a noble hybrid watermarking scheme joining informed coding and informed embedding approach to with the most utilized spread spectrum techniques. In informed coding, the codeword used to represent a message is dependent on the cover work in which message is embedded. In informed embedding, the embedding process tailors each watermark patterns according to cover work. Our informed coding is based on trellis, which is modified so that each message can be represented by set of alternative vectors. Our scheme first embeds a watermark using informed coding and informed embedding and to increase the robustness, another spread spectrum based watermark is embedded. The watermark added to our algorithm is perceptually invisible in nature. The effectiveness of this scheme is verified through series of experiments, in which a number of standard image processing attacks are conducted. The obtained results demonstrate, proposed algorithm survives a wide range of attacks.
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