The Research Of Digital Watermarking Based On JPEG

As an important technique of protecting copyright, digital watermarking widely gets the concern of the industry field and scientist 。 Currently it has got some results in the field. Compressing the image is inevitable for the sake of network bandwidth and storage resource. Image compression greatly impresses the digital watermarking, so the research of digital watermarking in compression domain has important interesting. Nowadays, digital watermarking in compression domain is in the entry-level and has many questions on it, such as algorithm is less, combining with other technique is insufficiency, thinking little about human visual system and so on. The topic of this thesis is meaningful because of these questions.The thesis mainly completes the following works based on the research of digital watermarking technique and JPEG compression technique:(1)It proposes several problems on watermarking in compression domain and gives some valid methods to deal with them in the designed algorithm.(2)It studies the pre-processing techniques and introduces two familiar methods of it。 The two methods is correct encode and scrambling change. It also improves the pre-processing technique by using double pre-processions. It uses correct encode after using the scrambling changes. The double pre-procession not only improves the concealment of the watermark but also strengths the self-correcting ability of it. It guarantees the robust of the algorithm.(3)It studies JPEG model and watermarking model and proposes an algorithm of watermark in compression domain. The algorithm combines the compression and the watermarking techniques. It also thinks about the characters of the image itself and the human visual system. It embeds the watermark in quantization course using self-adaptive strengthen ratio. The results of the experiment prove the algorithm is robust to the JPEG attacks.(4)It develops the algorithm according to the different type of the watermark. It...