A Fragile Document Watermarking Technique Based on Wet Paper Code

This paper proposes a new fragile watermarking algorithm which is mainly applied to binary document image based on the wet paper code. In order to improve embedding capacity and locating tampered area, some work is done base on the prior research of fragile in this paper. First, we dynamically adjust the bits which are embedded into image according to the number of turnover pixels and make the turnover pixels being fully useful, and then obtain larger embedding capacity. Second, original image is divided into blocks base on the content of it, and each block only includes a character or Chinese characters. According to the blocks of image, we can locate the tampered area after decoding. The experiment shows that this algorithm can detect the location of tampered image and get better embedding capacity that is near the number of turnover pixels.