Document image watermarking algorithm based on neighborhood pixel ratio

In this paper, a new method for document image watermarking is proposed. The method first divides the document into weight-invariant partitions in the spatial domain using a novel image feature - the neighborhood pixel ratio. Such a ratio effectively summarizes the local information and is robust to common attacks. The document image is then partitioned in a key-dependant way for high capacity and security. Our experimental results demonstrate the effectiveness of the new method.