Color image watermarking based on DCT-domains of color channels

Digital watermarking has been proposed as a method for discouraging illicit copying and distribution of copyrighted material. Now, there are many watermarking schemes for still color images, we present an approach for embedding digital watermarking information into color channel DCT (discrete cosine transform) domains of the image. We observe that the correlation value between the color channel DCT coefficients is satisfied with some kind of statistical regular, by means of this statistical regular, we can modify the selected sets of DCT coefficients to make the correlation values show specific distribution, so that we can embed a binary string into the image. Specifically, the embedded watermarking is extracted without resorting to the original image and any other data sets. Experimental results demonstrate that the watermark is robust to most of the image and signal processing techniques, and also our schemes are shown to provide very good results both in terms of image transparency and robustness.