A Robust Watermarking and Image Authentication Technique on Block Property

Digital watermarking is an effective and popular technique for discouraging illegal copying and distribution of copyrighted digital image information. One of the important features of the watermarking technique is the robustness of the watermarked image, which will preserve the quality of the retrieved watermark. There are two parts about robust oblivious watermarking scheme based on the frequency domain and image authentication technique is presented in this paper. One is the region used to hide the information is located at the middle frequency portion of the host image so as to provide good quality for both the watermarked image and the retrieved watermark. Such a scheme can provide a high degree of robustness against JPEG compression attacks. The other is signature process that input is the edge properties extracted from the image. The signature can be correctly verified when the image is incidentally damaged such as lossy compression. Experimental results are also presented to demonstrate the validity and robustness of the new approach.