Two-Dimensional Wavelet Filters for Watermarking

Discrete non-separable wavelet transform (DNWT) re- veals more features than discrete separable wavelet trans- form (DSWT) does. We propose to embed watermark by DNWT. To construct non-separable wavelet filters, we intro- duce a novel transformation ­ shift unitary transform (SUT) of conjugate quadrature filter (CQF). Based on this transfor- mation, a parametrization construction of two-dimensional wavelet filters is provided. Non-separable wavelet filters derived by this method are applied to a blind watermark- ing scheme. Experimental results show that watermarking scheme based on these filters is more resistant to sharpen- ing than watermarking scheme based on separable wavelet filters does.