A Robust Image Zero-watermarking Scheme in Combined DWT-DFT Domain
Yaxun Zhou, Yanhong Ji · International Conference on Electric Technology and Civil Engineering · 2012
In order to overcome the limitation of image quality degradation in the traditional digital watermarking scheme, which modifies the spatial or transform-domain image data to embed a watermark, a robust image zero-watermarking scheme for copyright protection based on the combined transforms of the Discrete Wavelet Transform (DWT) and Discrete Fourier Transform (DFT) is proposed in this paper. Instead of modifying the original image data, the proposed scheme constructs a zero-watermark from the image own features which extracts from the original body by applying the combined DWT and DFT. Firstly, the original image is decomposed into the appropriate levels by the DWT, and the DFT is applied to the obtained wavelet approximation sub-image, and then the DFT AC coefficients are selected according to the size of the actual binary watermark and the coefficient difference value. Finally, the embedding of zero-watermark is realized through the Exclusive OR (XOR) operation between the actual binary watermark and the binary key created by comparing the selected DFT AC coefficients. The simulation results demonstrate that the proposed zero-watermarking scheme has very good robustness against the common image processing such as noise addition, filtering and compression, especially free from geometric shift attack, while keeps the watermarked image quality without any distortion.