基于数字全息及离散余弦变换的图像数字水印技术

提出了一种以数字全息和离散余弦变换为基础的数字水印技术,实现了在原始图像中嵌入数字全息水印。考虑到数字全息图的不可撕毁性,使得数字全息水印本身就具有良好的抗剪切能力,并且与传统的二维灰度水印相比嵌入的信息更多。数字全息图通过傅里叶变换全息的方法获得,为了提高抗有损压缩能力,在数字全息水印嵌入过程中采用了基于(JPEG模型和分解离散余弦变换(DCT)系数的方法。实验表明,通过该算法获得的数字全息水印对JPEG有损压缩和剪切等图像处理操作均有很好的稳健性,并且采用密钥加强了水印的安全性。因此该算法能成为数字多媒体产品版权保护的有效方案。

An Image Digital Watermark Technique Based on Digital Holography and Discrete Cosine Transform

A new digital watermark technique based on digital holography and discrete cosine transform (DCT) is presented. The digital holographic watermark is embedded into an original image. Because the hologram can't be destroyed, the digital hologram watermark is constitutionally robust to cropping. It can embed more information than traditional methods. The digital hologram is obtained by the means of Fourier transform holography. In order to enhance its robustness to lossy compression, the watermark is embedded by using JPEG model and decomposing DCT coefficients. The experimental results indicate that the proposed algorithm is robust to many image operations, such as JPEG lossy compression and image cropping. And the application of security lock provides a good security. So this algorithm can be used to protect the digital multi-media's copyright efficiently.