Histogram modification based robust image watermarking approach

In the image watermarking community, developing a robust watermarking method has attracted increasing attention in recent years. However, protecting an image watermarking system against geometric distortions and common image processing operations with blind detection is still challenging. In this paper, a robust image watermarking scheme is proposed based on histogram modification since the histogram of a host image is approximately invariant to scaling and statistically independent to the position of pixels in the image plane. In the embedding end, the histogram of the host image is first computed and the bins with large population of pixels are then selected by a predefined threshold to form the appropriate embedding range. The watermark is then embedded in the host image by modifying the consecutive triple of bins belonging to the embedding range. In the detection end, global search incorporated with local search is exploited to retrieve the watermark. Experimental results confirm that the proposed image watermarking scheme can resist against geometric distortions as well as common image processing operations and outperforms the representative histogram-based image watermarking in terms of robustness.