Adaptive steganography method based on contourlet transform

In this paper, a new adaptive steganographic scheme based on contourlet transform is presented that provides large embedding capacity. In this method, embedding is done in contourlet transform domain. The contourlet coefficients with larger magnitude that correspond to the edges are selected for embedding. This selection is due to less sensitivity of human eyes to non-smooth regions. Each bit of secret data is embedded by exchanging the value of two coefficients in a 4 times 4 block of a contourlet subband. The proposed method is examined with two strong steganalysis algorithms and the results show that we could successfully embed data in a cover image with the capacity of 0.05 bits per pixel. Experiments and comparative studies showed the effectiveness of the proposed technique in generating stego images. In addition, its superiority is shown by comparison with a similar wavelet-based steganography approach.