Watermark Resisting Local Geometric Attacks Using Composite Chaos and RMSBM in NSCT Domain*

摘要

To improve the weakness of unsafety and poor robustness to local geometric attacks in the existing schemes, a new watermark algorithm is proposed in this paper. The presented composite chaos is used to scramble the watermark for enhancing the algorithm security. A new registration method noted as radial multi-scale block matching (RMSBM) is given to correct effectively the attacked images by local geometric distortion. The watermark is embedded according to the principle of human visual system (HVS) in nonsubsampled contourlet (NSCT) domain, and the maximum-likelihood (ML) detector is used for the extraction of watermark. The simulation shows the developed algorithm has stronger robustness to signal processing and local geometric attacks than other similar algorithms.