Visually imperceptible and robust image watermarking 

Watermarking is a new impressive digital copyright protection method and data security technology. The image watermarking algorithms can be grouped into two groups depending on the domain of watermarking, i.e., the spatial and transform domain. Usually, the transform-basedwatermarking approaches can efficiently hide a robust watermark due to the utilization of the characteristics of human visual system (HVS). In this paper, we propose a watermarking algorithm based on contourlet transform.

The contourlet transform is one of the recently developed multiscale transforms that are more appropriate for image processing tasks in contrast with other transforms such as Fourier and wavelets. In this base, the proposed algorithm in this paper stores the digital logo as side information by average quantization of selected contourlet coefficients in arbitrary subbands. The proposed data embedding method is imperceptible and robust against several common watermarking attacks such as compression, adding noise, filtering and scaling.