菲涅耳数字全息在图像加密中的应用

Application of Fresnel digital holography in image encryption

基于小波变换和光学菲涅尔变换原理,提出一种新的数字水印算法。首先,原始的水印图像经过离散菲涅尔变换转化成数字全息图,并对数字全息图进行灰度变换;再对宿主图像进行一层小波分解;最后将变换后的数字全息图嵌入到宿主图像较大的小波系数中。实验结果表明,该水印算法具有较强的鲁棒性,能抵抗较大的剪切、有损压缩和滤波等攻击。

A new digital watermark technique based on digital holography and discrete wavelet transform is presented. Firstly, the secret image is transformed into a digital hologram image by the means of discrete Fresnel diffraction. By one level wavelet transform, the host image can be presented by one low frequency approximation and three high frequency details. Lastly,the digital hologram image is embedded into the large wavelet coefficients. The experimental results show that the method is robust to the attack of the JPEG lossy compression, cropping and average filter.