Study Of Data Hiding In Video And Technology Of Digital Watermarking

Information hiding is an important method for multimedia data protection. Data hiding in video and digital watermarking are two domains of information hiding.For data hiding in video, this paper makes use of the principle of image scrambling to present an encrypt method for videoconference system. It adds a scrambling module and an inverse scrambling module in videoconference system. The user' s data are scrambled before they are transmitted in network, and at the receiver, the received data are inversely scrambled in order to get the user' s data.For digital watermarking, fragile watermarking is studied. It can be used to prove whether an object has been tampered with and whether the object is credible. This paper improves a fragile watermarking method based on space domain, and proposes a new fragile watermarking method based on the combination of DCT (Discrete Cosine Transform) and DWT (Discrete Wavelet Transform). For the former, watermarks are embedded into the two lowest bits of digital image data. For the latter, firstly, we compute the L-level discrete wavelet decomposition of the original image to produce a gross approximation of the image at the coarsest resolution level, and a sequence of three L- detail images, corresponding to the horizontal, vertical, and diagonal details at each of the L-resolution levels. Then we compute the discrete cosine transform of the gross approximation of the image and the detail images. Lastly, watermarks are embedded into the selected parts in the DCT matrixes. The selected parts are the bottom right parts in the DCT matrixes of the gross approximation of the image, the bottom left parts in the DCT matrixes of the horizontal detail images, the top right parts in the DCT matrixes of the vertical detail images, the bottom right partsin the DCT matrixes of the diagonal detail images. The second method makesfull use of HVS(Human Vision System), and is in favor of invisibility and fragileness of the watermark.