Research On Digital Image Watermarking Based On Binary Hologram

With the development of digital techniques，the infringement of digital products havebecome increasingly seriously. Because of non-tear of holograms, digital watermarkingtechnology based on CGH is a new type of information hiding technology to effectivelysolve the problem of information security. This paper studies new approaches of digitalwatermarking using binary hologram based on information optics theory, which obtainbetter performance.The holography used in traditional holographic watermarking are all grayscale imageswith a large amount of information. Therefore, in order to reduce the embeddedinformation, this paper propose new scheme of hologram binary. But the direct binarizationprocessing of the hologram will lose much holographic information and the reconstructedimage quality is poor. In this letter, two new methods of holography binarization based oniterative conjugate-symmetric extension and phase retrieval algorithm and the quality ofreconstructed image is greatly improved.Binary hologram is taken as watermarking. Hologram is scrambled and thenembedded into discrete cosine transform (DCT) of host image. Watermarking is extractedin the form of blind detection. The simulation and contrastive results show that thealgorithms have much better robustness to JPEG compression, cropping, filtering, noisecontamination and other common image processing. Compared with traditional method ofbinary Fourier CGH, the robustness of the watermark has been significantly improved.