| Summary: | 碩士 === 國立屏東商業技術學院 === 資訊工程系(所) === 101 === In recent years, fragile watermarking technology has been widely used for content authentication and recovery of digital images. A self-embedding fragile watermarking scheme, which authentication and recovery information are embedded into the original image, is designed to realize tampering localization and content restoration.
In this thesis, a novel scheme is proposed for image authentication and recovery. Firstly, the original image is decomposed by the discrete wavelet transform (DWT) and the low- frequency wavelet coefficients are used for image authentication. Secondly, the original image is divided into several non-overlapping blocks and each block is transformed using the DWT decomposition. Thirdly, by the use of low and middle frequency characteristics of each block, the low-frequency coefficients are embedded into the middle-frequency subbands for image recovery. Furthermore, a linear calculation is used to predict the intermediate value between two image coefficients. Finally, experimental results show that the proposed method can be used to localize the tampered blocks and the use of a linear calculation to recover the original image achieves an accurate restored image.
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