Wavelet Domain Fragile Watermarking For Image Authentication

In order to solve the security problems of the multimedia information on Internet, the digital watermark technology has gained extensive concern since it's arisen and it has already become a researching hotspot of international academia at present.The research works of this article mainly include several aspects as follows:1. Wavelet analysis theories is researched, which include the first and the second generations of wavelet transformation, the basic concept, principle and algorithm, especially the multi-resolution of wavelet and the lifting scheme theory of the second-generation wavelet. The research contents about digital watermark are introduced systematically, and the general principle and universal model are summarized and the primary applied prospect is also pointed out. Then the various typical algorithms and the primary attack mode are analyzed.2. The authentication technology of image is analyzed in detail, and the advantages and disadvantages between the authentication of digital signature based on traditional cryptography theory and the authentication watermark technology have been compared. The basic scheme and the correlative request needed by two watermark algorithms of fragile and half-fragility digital watermark technology have been summarize systematically discussed the various researches in recent years about the two kinds of watermark technologies, analyzed the integrality authentication differences between two attacks.3. Utilizing the HVS and the characteristic which integer wavelet analyzes the high-frequency coefficient to express the image detail, proposed the definition of energy coefficient. According to the sub-blocks from different groups, the computed energy coefficients were different. When embedding watermark it archived the purpose of self-adaptation control on watermark imbed quantity according to different coefficients. Also by embed watermark into the high-frequency coefficients in three different directions, it reduced the influence of energy on one sun-band and then the visual effect of restored image were greatly perfect. At the same time, it can detect the operation of illegally juggle on image content, and the...