Research Of Military Image Information Hiding Algorithm Based On Lifting Wavelet Transform

With the rapid developments of the computers, networks, multimedia and digital signal processing technologies, the research of information hiding has become a hotspot again in technological fields. Information hiding technique has very wide applications. One of the applications of information hiding is confidential image information hiding, therefore, becomes important particularly in national security and military section.The technique of Information hiding and digital watermarking is the research hotspot in the fields of information security. It uses the redundant spaces in multimedia information to carry masking information. It is applied in many fields such as steganographic communication, copyright protection and data authentication. For some important images such as remote sensing and SAR, which arecharacteristic as huge capacity, high price and further demand for security, some information in it should be only visible to the authorized users. And the sensitive part of the picture such as military base information must be invisible for those unauthorized users. So it has very important studying value and practical meaning for research on secret information hiding of these important images.Starting from the problems in image information security and confidential information hiding, this dissertation make a wide and deep research on the current hotspot in information security field such as Information hiding and Digital watermarking techniques. By using the modern theory, method and techniques, the dissertation has deeply researched on the hot point of digital watermarking, which is CR image information hiding algorithm based on lifting wavelet transform.Based on the researching of relevant documents domestically and overseas, this research is mainly aiming at the dynamic research of the information hiding technology in the field of military, integrating the application of this technology in the real condition, focusing on the digital watermarking of military images on the basic of CR zoon, combining the current information hiding technology with digital watermarking technology. This research extracts the CR image block from original photograph, takes the useless part as the carrier and hides the CR image block as digital watermarking information. It fully considers the integrating of information hiding and watermark robustness and mainly discusses the following parts:1. Much more attention has been paid in the domestic and oversea development process and trend, existing problems and research hotspot of the information hiding and digital watermarking. On the basis of thorough research on information hiding theory and its relating techniques, this dissertation analyzes the problem in digital watermarking, discusses the main topic and the solutions of this subject, and also explained the basic theory of digital watermarking technology.2. Researching of image watermarking technology in wavelet domain, it discusses the wavelet transform in the field of digital watermarking, analyses the advantages of embedding watermark in wavelet domain and the current watermarking algorithm in wavelet domain, introduces the relevant pretreatment technologies of watermark signals. Because the LWT inherits the multi-resolution character of the first wavelet generation and all calculations is processed in space domain, the quality of image recovery is irrelevant to the extension method using in boundary switch, so that there are advantages as the size of image is not limited and the calculation speed is faster and the hardware is easier to achieve. This research introduces application proposals of LWT in the field of information hiding.3. The current information hiding and digital watermarking technologies are fully integrated in this research. It combines the analysis of SAR image and satellite images, introduces a calculation method on the basic of analyzing LWT and CR that extracting the confidential information in image based on the theories of lifting wavelet and CR extraction method. It also has experiments about SAR images and satellite images. This calculation fully realizes the unpredictable and the tolerant of JPEG compression that shows some robustness. It is a practical calculation method of information hiding watermarking.4. This research not only improves the calculation method of information hiding watermarking of wavelet CR images, but also improves the calculation method of watermarking pretreatment aiming at the application in the real military condition that enhanced the robustness and security of the calculation method. The comparison of the results from experiment proves that this calculation is better in robustness and hiding effects that is more suitable for the military with high confidential standards and bad transmission environment.1. Based on the applications of image information hiding in military concealed communication system, combining the information hiding and digital watermarking deeply with the digital image, a wavelet domain algorithm of digital image secret information hiding based on Lifting Wavelet Transform and confidential region (CR) is proposed. Firstly, we segment and extract the CR information block in original image, and then make gray value supplement in that region to generate the disguised cover image. The CR watermarking information encrypted by chaos is embedded into the disguised cover image in lifting wavelet domain, and then the watermarked image is obtained.2. The experimental results show that the algorithm is of huge hiding information capacity, high imperceptibility and strong robustness, and blind detecting is available. And the algorithm performs well against various attacks such as cropping, salt & pepper noise and JPEG compression. So this algorithm has important practical value of information security to the transmission of important picture such as remote sensing, SAR image and etc.3. This research introduces the relevant technology in watermark signal pretreatment and uses the relevant technology to improve the wavelet domain algorithm of digital image secret information hiding which based on Lifting Wavelet Transform and confidential region (CR). The comparing lab research result shows that this method is better in robustness and cryptic effect which will be more suitable for the field of military which with the strict confidentiality standards and severe working environment.