An Adaptive Watermarking Scheme Based on Nonsubsampled Contourlet Transform for Color Image Authentication

In this paper, a new semi-fragile watermarking scheme based on Nonsubsampled Contourlet Transform (ASCT) for color image authentication is proposed, in which the watermarking is embedded in the SVs(singular values)of the blocks within NSCT subbands by an adaptive quantized method. The eye is insensitive to the blue color so the transform is used in the blue segment of the color image. NSCT is a redundant transform that can increase the capacity of the watermarking and improve the tampering localization capability without causing noticeable artifacts. In order to improve the security of the scheme, a new two-dimensional transformed network generated by the low-dimensional Tent chaotic map is used to encrypt the embedded watermarking. The results of the experiments show that the proposed scheme is robust to JPEG compression but extremely sensitive to malicious manipulations such as translation and rotation.