基于人类视觉系统的非抽样Contourlet变换域图像隐写算法

Image steganography algorithm based on human visual system and nonsubsampled contourlet transform

为提高图像信息隐藏的容量和隐蔽性,对比分析了非抽样Contourlet变换(NSCT)和Contourlet变换各自的优缺点和适用范围,提出了一种基于NSCT和人类视觉系统(HVS)的图像隐写方案。通过对人眼的视觉掩蔽效应进行建模,在NSCT分解的最精细尺度的各方向子带中,对不同系数分别嵌入不同的秘密信息量。仿真实验表明,新的算法相比小波域中的隐写方案,隐写的嵌入量至少提高了70000 b,峰值信噪比(PSNR)提高约4 dB,较好地兼顾了隐写在不可见性和嵌入容量上的要求,较小波域中的隐写方案具有更好的应用前景。

To improve the capacity and invisibility of image steganography, the article analyzed the advantage and application fields between Nonsubsampled Contourlet Transform （NSCT） and Contourlet transform. Afterwards, an image steganography was put forward, which was based on Human Visual System （HVS） and NSCT. Through modeling the human visual masking effect, different secret massages were inserted to different coefficient separately in the high-frequency subband of NSCT. The experimental results show that, in comparison with the steganography of wavelet, the proposed algorithm can improve the capacity of steganography at least 70 000 b, and Peak Signal-to-Noise Ratio （PSNR） increases about 4 dB. Therefore, the invisibility and embedding capacity are both considered preferably, which has a better application outlook than the wavelet project.