Quaternion Frequency Watermarking Algorithm for Color Images

A new method to embed the watermarks in the amplitude of the quaternion is proposed this paper. Firstly, ununiformity of each unit quaternion block in host image is calculated to pick up the potential block adaptively. Secondly, frequency matrix of host color image is obtained by using quaternion Fourier transform. After that, the water marks are embedded into the amplitude of AC coefficient. Experimental results verify the effectiveness and superiority of the proposed algorithm.