Watermarking Algorithm for Color Images Based on Quaternion Frequency Modulation
彩色图像四元数频域幅值调制水印算法

Separate channel technictues performed on color images have the disadvantage of less ability to show connection between each channel during image processing. A new method to process color images with quaternion Fouricr transform was put forward in this paper. Firstly, ununiformity of each unit quaternion block in host image was calculated to pick up the potential block adaptively. Secondly, frectuency matrix of host color image was obtained by using quaternion Fouricr transforms. After that, the water marks were embedded into the amplitude of AC coefficient. Experimental results show that the image distortions from the watermark are spread into the three channels of a color host image and the proposed watermarking algorithm realizes a better trade off between imperceptibility and robustness.