A technique for optimum distribution of watermark in a document image

Abstract

Watermarking is a very useful technique to ensure the integrity of a document image. But when too many bits are embedded into image, it reduces quality of the document. When limited number of watermark bits are used, these should not be concentrated in background or few parts of the image. As very few existing techniques address this issue, in this paper, we propose a watermark distribution scheme, which divides image into optimum number of segments and distributes watermark based on information content such that watermark is well spread across the document. After embedding, on average the proposed scheme achieves 31.79% more area with ensuring 38.59% better quality in terms of PSNR compared to state-of-the-art schemes.