加密同轴全息数字水印

Digital watermarking of encrypted in-line holography

在研究数字全息技术的基础上,提出了一种新的加密的同轴全息数字水印方法。该方法包括加密和解密两个过程。加密过程首先将原始二值水印图像经过输入面和频谱面上分别放置随机相位模板进行调制加密,生成加密的复数图像,将其作为物光信息,再与参考光信息叠加生成同轴全息图像,然后将其作为水印嵌入到载体图像中;解密过程是加密过程的逆过程,水印重建不需要原始图像的参与,属盲检测过程。在理论分析部分证明了该水印技术的有效性,在仿真实验部分证明了该水印技术具有抗随机噪声干扰、剪切干扰、有损压缩和低通滤波等常见的干扰能力。文中还详细研究了全息数字水印的嵌入强度及对应恢复水印的效果。

A new encrypted in-line holographic watermarking technique is proposed based on doublerandom phase encoding method, holography and digital watermarking. The proposed method includes two processes of encryption and decryption. In the encryption process, a digital watermark image is modulated by double-random phase encoding, and its in-line hologram is superposed on a content image. The watermark is recovered by means of holographic reconstruction and calculations in reverse order of encryption process without the information of the content image （blind detection）. Analysis and computer simulation prove that the encrypted holographic watermark is valid, robust and secure. The watermark can be recovered from the watermarked images distorted by noise added, JPEG compression, part occluded and low pass filter. The conditions for superposing the hologram onto the con- tent images are also investigated in detail