Robust image watermarking research based on DCT transform

Digital watermarking has been proposed as a solution to the problem of copyright protection of multimedia data. But, most watermarking methods, especially the ones based on the frequency domain, can not satisfy the robustness requirement of some geometry attacks such as cropping and so on. To get around this problem, in this paper we proposed a new algorithm based on the DCT field which uses some specially-designed techniques. Experimental results demonstrate that the watermark algorithm we propose is really very robust to cropping attack and other signal processing including JPEG compression, addition of noise etc.