Study On Digital Watermarking Based On Chaos

With the quick development and wide application of the technology of network and multimedia, more and more digital information spreads quickly. Digital signal processing and network transmission technology can be used to edit, modify, copy, and distribute digital products (audio, text, image, and video) arbitrarily. This brings problems of intellectual property and information security. Watermarking is an effective solution for this problem.Digital watermarking embeds the tag in the product, and use digital methods to validate the authors'property. At the same time, this technology can also be used to extract and detect watermark in the products, which is used to ensure the data integrity and reliability. So watermarking becomes an effective method for copyright and authenticity protection.Chaotic sequences have good features such as noise-like, unpredictability with deterministic orbits and sensitivity to initial condition and parameters, so chaotic signals are suitable for digital watermarking application.In this work, we select digital image as watermarking object, and use chaotic system, the Logistic mapping to generate chaotic sequence for the embedding of watermark. The author designs a new fragile watermarking algorithm, which combines two different methods to embed watermark so as to ensure the authentication of image.The author designs a DWT (Discrete Wavelet Transform) watermarking based on chaotic sequence. Information of original watermark image is embedded in wavelet parameters according to the importance of planes by multi-level wavelet decomposition. This algorithm is easy to realize and it has the attribute of robustness and resistance to some kind of image attacks.We prove the feasibility of two algorithms by experiments. The watermark is invisible and the embedding doesn't result in change of original image's vision. So it can be utilized in project.