Study On The Application Of Compressive Sensing In Image Watermarking Algorithm

With the development of multimedia technology, more and more multimedia resources are transmitted by network. However, the popular use of transmission increases the chances of tampering. Digital image with its intuitive, vivid and visual characteristics is used more and more frequently in people’s lives. How to protect the security of digital image is an urgent problem to be solved.Reversible image authentication relies on reversible watermarking embedding. It not only can make a reversible authentication for image content, but also can realize tamper localization and recovery. So it can be applied in the areas of military or law image where there is high requirement on image quality. As an emerging topic, watermarking in encrypted images, which can achieve effective management and control of the digital images while protecting their privacy, has a broad application prospect in the information and networked environment in the future. Compressive sensing(CS) technology can break the constraint of Nyquist sampling theorem on the sparse signal. Under the environment of limited bandwidth and large data transmission quantity, the application of compressive sensing technology in the digital image watermarking algorithm is of very important academic significance.The works of this thesis include the following three aspects:①Research and analysis on the existing algorithms of reversible watermarking, watermarking in encrypted images and compressive sensing are done so as to find the possible combination of compressive sensing and reversible watermarking or watermarking in encrypted images.②A reversible image authentication scheme based on CS is proposed. It employs a dual watermark authentication scheme to achieve reversible authentication as well as tamper localization and recovery. In the proposed algorithm, CS is used to generate the two watermarks. The long watermark is registered to Intellectual Property Rights(IRP) database in zero-watermarking way, while the short watermark is embedded into the original image in a reversible way and the embedding method is based on histogram modification of discrete Haar wavelet coefficients which is proposed in this thesis. The experimental results show that the proposed algorithm performs better than other authentication algorithms on imperceptibility and authentication efficiency.③A novel scheme for robust and separable watermarking in encrypted image based on CS is proposed. The Prewitt edge-detection method is utilized to classify all blocks into significant or insignificant blocks. For the former, traditional method is used for encryption; and for the latter, CS is used for encryption, which leaves some space for embedding data. The way to obtain the image content and watermark is separable without order. The experimental results show that the proposed algorithm meets the requirements of the embedded capacity; what’s more, the proposed scheme is robust and secure against moderate attacks.