A Robust True-Color Watermarking Scheme Based on Discrete Cosine Transform

A watermarking technique for true-color image based on double random phase encryption method and digital holography is proposed. Three different watermark images are encrypted into three holograms, respectively. Then, three holograms are hiding into a true-color image. Watermark extract method has also been described detailedly. Simulation Results indicate that our proposed watermarking technique can resist physical attack well and has a high security degree of hidden information.

A New Robust Color Image Watermarking Based on DWT and DRT

The copyright protection of multimedia information is more and more important in the digital age, digital watermarking is a solution to address the topic. This paper proposes a new robust image watermarking scheme based on discrete ridgelet transform (DRT) and discrete wavelet transform (DWT). The scheme respectively embeds a copy of color image watermark into DWT domain and DRT domain, and uses a conception of semi-watermark. Experiment results demonstrate that the watermark can resist various attacks such as adding Gaussian or Union Distribution Noise, JPEG compression, brightness adjustment, contrast adjustment, altering color balance, lens blur, zooming in or out, cropping and some combined attacks etc.