| Summary: | 碩士 === 國立聯合大學 === 資訊工程學系碩士班 === 104 === Digital media is very more enough as a result of the digital technical development. Also, techniques on the Internet and digital edictal software are progressed, so digital media is easily tampered by the intended people and distributed by the Internet. Thus, digital media authentication technology is become more important issue nowadays.
To preserve of digital image integrity, layer tree structure image authentication technologies by using Discrete Wavelet Transformation (DWT) are proposed in this thesis. The layer tree structure of digital image DWT coefficients and the similarity of are sub-bands coefficients are explored to develop the proposed methods. In addition, the global and local characteristics in DWT coefficients are applied to achieve an efficient authentication technique. In the proposed two methods, the LL sub-band DWT coefficients are taken as the authentication code and embedded into the other sub-bands according to the global and local characteristics. The embedded authentication code is retracted to verify the image authentication. Furthermore, the tampered areas can be detected and located if the image is unauthenticated. The experimental results shown the proposed methods can not only detect the image tampered areas but also distinguish the generation image operations from intended manipulations.
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