Fragile image watermarking with pixel-wise recovery based on overlapping embedding strategy.

Overlapping-block embedding strategy is introduced in the proposed scheme.Two possible embedding modes are utilized for the blocks based on the locations.Authentication-bits are generated according to the complexity of each block.Block-wise tampering detection and pixel-wise content recovery are collaborated.Better tampering recovery performance can be achieved than some of reported schemes. In this paper, we propose a new fragile watermarking scheme with high-quality recovery capability based on overlapping embedding strategy. The block-wise mechanism for tampering localization and the pixel-wise mechanism for content recovery are collaborated in the proposed scheme. With the assist of interleaving operation, reference bits are derived from mean value of each overlapping block, and then are dispersedly embedded into 1 LSB or 2 LSB layers of the image, corresponding to horizontal-vertical mode and diagonal mode, respectively. Authentication bits are hidden into adaptive LSB layers of the central pixel for each block according to block complexity. On the receiver side, after locating tampered blocks and reconstructing mean-value bits, according to the types of tampered pixels in each overlapping block, three pixel-wise manners are exploited for tampering recovery based on different neighboring blocks. Even if the tampered area is extensive, the proposed scheme can achieve better quality of recovered image compared with some of state-of-the-art schemes.