Robust and reliable image copyright protection scheme using downsampling and block transform in integer wavelet domain

Abstract In this paper, a robust watermarking algorithm in integer wavelet domain using downsampling is proposed. The innovations of this paper can be summarized as follows. First, after downsampling both the host image and watermark, each sub-watermark is embedded into the corresponding sub-host image. Second, four sub-watermarks are encrypted by pixel scrambling and fractional random transform, and the right principal component of watermark is embedded in the host image to avoid false positive problem. Third, two-level singular value decomposition and block cosine transform are performed on host image and watermark respectively, and the dual embedding of watermark is realized. Fourth, guided dynamic particle swarm optimization is used to optimize the embedding factors. The simulation results show that the proposed watermarking algorithm satisfies the requirements of robust watermarking very well. It has large capacity and strong robustness to common attacks. Moreover, compared with the existing related algorithms, this algorithm has obvious advantages.