A Digital Watermarking Algorithm based on Hyperchaos and Discrete Fractional Fourier Transform

Based on hyperchaos and discrete fractional Fourier transform (DFRFT) algorithm, a digital image watermarking algorithm based on hyperchaos sequence and the discrete fractional Fourier is presented in this paper. First, the original image and the watermarking image are transformed, respectively. At the same time, according to cipher sequence generated by the hyperchaotic array, the watermarking image's real part and imaginary part are encrypted, respectively. Second, the encryption watermark image's real part and imaginary part alternative embedded into the host FRFT coefficients. Then, the watermarking image is obtained after Fourier inversely transformed. Moreover, different attacks such as noise, JPEG compression and the cropping have been analyzed for the robustness of the watermark image. The results of the experiment have shown that the proposed algorithm is robust against common image manipulations.