Chaos-based Fragile Watermarking Technique for Binary Image Authentication and Ownership Verification

摘要

A novel watermarking method in binary document image for secure authentication and ownership verification is described. The image pixels are divided into two groups according to a previous CSC measure, one is the “flippable” pixels, and another is the “unflippable” pixels. We map the unflippable pixels into the initial value of a chaotic map, and generate the watermark by iterating the chaotic map from the initial value. Then we substitute the flippable pixels with the watermark to obtain the watermarked image. We developed the hierarchical watermarking method with two hierarchies in binary image authentication. The first hierarchy is designed to localize the modifications, and the second hierarchy is designed to authenticate the whole image and verify the ownership. Simulation results show the imperceptibility of the watermarking process and successful detection and localization of content modifications. The ownership information will reveal correctly only if the image is authenticated, otherwise it will resemble random noise.