Capacity and quality improvement in reversible image watermarking approach

This paper proposes a high capacity reversible image watermarking scheme based on enhancement of difference expansion method. Reversible watermarking enables the embedding of useful information in a host signal without any loss of host information. We propose an enhancement of Difference Expansion technique whereby we can embed recursively into multiple layer of payload for grey scale and also RGB color scale, hence it increase capacity much better. The proposed technique improves the distortion performance at low embedding capacities and mitigates the capacity control problem. We also propose a reversible data-embedding technique with blind detection of watermark. This new technique exploits the selection of optimum block size to implement the algorithm. The experimental results for many standard test images show that multilevel of embedding increase the capacity when compared to normal difference expansion. There is also a significant improvement in the quality (PSNR) of the watermarked image, especially at moderate embedding capacities.