Gyrator变换域下基于超混沌相位掩模的光学水印方法

Optical Watermarking Method Based on Hyper-Chaotic Phase Mask in Gyrator Transform Domain

针对光学变换水印算法中光学实现的轴对准问题和光学密码系统的安全性问题,提出一种基于超混沌映射和Gyrator变换的光学水印方法。利用Chen 4D超混沌系统构造超混沌相位掩模,然后通过菲涅耳波带板和径向希尔伯特掩模构造的涡旋光,对超混沌相位板进行照明,最后借助Gyrator变换将加密后的水印图像植入宿主灰度图像,实现Gyrator变换域下的光学信息隐藏。通过Gyrator逆变换提取目标图像中植入的水印信息。实验结果表明,该算法能够从高不可感知性的目标图像中提取高质量的水印信息,加密的目标图像信噪比高,与宿主图像的相关性强,能够有效地抵御强度系数为0.06和0.8的椒盐噪声和高斯噪声的攻击,对低于50%遮挡率和80压缩因子的攻击具有良好的稳健性。加密后的目标图像与原始宿主图像具有相似的统计分布,较好地实现了信息隐藏。

Aiming at the problems of optical alignment in optical transform watermarking algorithm and the security of optical cryptosystem,an optical watermarking method based on hyper-chaotic mapping and Gyrator transform is proposed.The hyper-chaotic phase mask is constructed by using the Chen 4 D hyper-chaotic system,and then the vortex light constructed by the Fresnel zone plate and the radial Hilbert mask is used to illuminate the hyper-chaotic phase plate.Finally,the encrypted watermarking image is embedded into the host gray image by means of Gyrator transform to realize optical information hiding in the Gyrator domain.The Gyrator inverse transform is used to extract the watermark information embedded in the target image.The experimental results show that the algorithm can extract high-quality watermarking information from highly imperceptible target images.The encrypted target image has a high signal-to-noise ratio and strong correlation with the host image.It can effectively resist salt and pepper noise and Gauss noise attacks with intensity coefficients of 0.06 and 0.8 respectively,and has good robustness against attacks with less than 50%occlusion rate and 80 compression factor.The encrypted target image has a similar statistical distribution compared with the original host image,which realizes information hiding well.