Watermarking technique based on discrete non-separable wavelet filters

This paper presents a digital watermarking technique based on the discrete non-separable wavelet transform (DNWT). In our paper, the discrete non-separable wavelet is constructed based on the standard dilation matrix 21. Our investigation demonstrates that the constructed discrete non-separable wavelet can detect more singularities of the host image with reflecting whole orientation while only three orientations being considered by traditional discrete separable transform (DWT). For this reason, more coefficients in the high- frequency sub-bands by DNWT can add the watermark than that by DWT. By using the desirable character of DNWT, the imperceptibility and robustness requirements of watermarks are fulfilled. Experiment results show that the watermarking scheme based on DNWT is robust to some distortions such as noising, JPEG compression, and cropping. It also shows that the decomposing of the host image and the robustness of the watermark are relating to the parameters.