A triple self-embedding fragile watermarking scheme for image tamper detection and recovery

This paper presents a new triple self-embedding fragile watermarking technique for image tamper detection and recovery. This approach divides the host image into non-overlapping regions according to the block map and further divides each region into 5×5 non-overlapping blocks. For each block, block directions are obtained from the adjacent pixel differences. The recovery information for each block is constructed by computing the block directions, differences of the directions and the mean value of each block. The authentication information for each block is generated using an Singular Value Decomposition (SVD)-based approach. The recovery information is embedded in three different blocks determined using a block map while authentication information is embedded in the block itself using the three least significant bits. The developed approach provides a triple recovery opportunity for each block due to the triple embedding. Consequently, the watermark constructing and embedding processes of this approach provide more successful image tamper recovery than the methods based on average values of blocks. The proposed approach has been evaluated against various attacks and compared with state-of-the-art methods. Experimental results shows that the proposed approach can resist attacks up to 75%.