Information Hiding Technology Based On Wavelets And Multiscale Geometric Analysis

To protect security and copyright of information, the information hiding technology has been developed greatly in recent years. It has been used widely in many aspects of human life. The research on it currently focused on two things:steganography and digital watermark. The first one is to study how to insert confidential information into messages secretly which will not draw people's attention and make the secret communication hard to be detected. The latter one is proposed for the copyright privacy of digital media. Both of them are the latest hotspot of information security fields.Based on the analysis of the defects of the traditional information hiding algorithms, new methods for solving these problems are proposed in this paper. A series of researches on the design of algorithms, detection of the hidden information, its capacity and the ability for defending attacks and so on, have been done. The main original works include:As all tests of the traditional digital watermark method are executed by contrasting embedded information point by point. The watermark is detected based on the calculation of the similarity. A watermark is proved to be existed when the similarity reaches a certain threshold. However, it easily leads to wrong judgment and reduction of the discrimination. Furthermore, it is too complex to be realized. Considering these shortcomings, the watermark algorithm for image authentication based on the second generation Bandelet and the one for geometric image authentication based on directional wavelet are proposed here. Moreover, the adaptive noise intensity algorithm based on the statistical models is improved. The former depicts the texture and geometric features of the image by adopting the second generation Bandelet transformation to generate geometric direction flow of the image. The latter realizes the goal by using directional wavelet transformation to generate the flow. Both of the two methods take advantage of the adaptive noise intensity algorithm, to filter out subgraphs owning rich texture for hiding information. The experimental results show that these two algorithms are not only able to embed the information of directional flow of image confidently and then detect it, but also withstand the typical attacks such as fuzzy, JEPG compression, noise and others.To fix the weakness that the present texture DEM data hiding algorithms damage that texture, the texture DEM data hiding algorithm without data lost, which is based on wavelet, is proposed. It uses the wavelet-based method of 3d DEM data compression of extreme small bit rate, adopts histogram-shift non-destructive hidden algorithm to embed the compressed elevation data into the texture image, and extracts the hidden DEM data from the image with the reversible histogram-shift algorithm. Moreover, a lossless recovery of the texture image is realized.According to the characteristic of DEM data, the non-destructive three-dimensional terrain data watermark signature technology based on directional wavelet, and visible three-dimensional watermark technology based on DEM data are developed. The former is to detect the trend and direction of the 3d terrain by the means of directional wavelet transformation, then hides them as authentication watermark, and inserts the data by modifying the translation algorithm of generalized histogram. The latter is the three-dimensional integration of three-dimensional watermark and DEM data, which embeds the three-dimensional watermark information into DEM data by the translation algorithm of histogram, meanwhile recording the information marked by three-dimensional watermark, replaces three-dimensional watermark with the information marked by three-dimensional watermark, which is extracted by the reversible algorithm of generalized histogram, and then recovers the original DEM data. The experimental results show that the wavelet can describe the feature of three-dimensional DEM data terrain well, when ensuring a high peak noise ratio (>40dB) and a great amount of hidden information can be embedded (>16kb) with the guarantee that the DEM ground texture data is plenty enough. The larger the visible three-dimensional watermark is, the greater the amount of hidden information is.To improve visual effects of fused image, and provide illegal user removing the visible watermark, the relative fuzzy relation based on wavelet coefficient and the lossless visible watermark based on fuzzy relation are proposed. Fuzzy relationship matrix is constructed by applying Rabin's function. And diagonal components and approximate components modulo the weight of the quantization noise of wavelet. Relationship of remainder is used to embed watermark. The experiments show that, for the former, its quality is still very high when watermarks are embedded, what's more, the watermarking algorithm has strong attack-resistance ability and the original image doesn't need to be participated in the process of watermark extraction. The later, carrier fused with visible watermark firstly. Secondly, encrypt the block subgrah by applying RH function. Finally, an improved histogram shifting method achieves information hiding and recovery. Because the algorithm adopts Hash operator encipher shading sub-graph which is constructed by Rinj indael, it lets 1 bit diffuse into the whole image, thereby it can protect the image data, so this algorithm has highly security.