A novel color image hologram watermarking algorithm based on QDFT-DWT

In this paper, we propose a novel color image hologram watermark algorithm based on quaternion Fourier transform (QDFT) and discrete wavelet transform (DWT). Firstly conduct 2-level discrete wavelet transform on the real part of QDFT coefficient. Then the middle frequency wavelet coefficient of the real part of QDFT coefficient is replaced with holographic watermark information. Quaternion be used in process color image spread image distortion that caused by watermark embed into three channels simultaneously rather than into only one channel and combined transform domain provides a more covert embedding area, that make the algorithm have a good performance in invisibility. Computer-generated holography technology and middle frequency wavelet coefficient domain embedding manner provide a robustness guarantee. Experiment results show that the application of the color image watermarking algorithm well balanced the relationship between the robustness and transparency, and the algorithm can resist lithography and scanning attack.