基于信噪比的完全自适应灰度图像水印算法

Absolutely Adaptive Gray Image Watermarking Algorithm Based on PSNR

不可见性是图像隐形水印最基本的要求之一,它的客观标准是水印图像的信噪比。根据这个标准,提出了一种简单的基于小波的以灰度图像为水印的自适应水印算法:即根据需要的水印图像的信噪比,对于不同的宿主图像和水印,用一维搜索法都能够自适应地选择水印的嵌入强度,避免了以经验或实验办法确定嵌入强度的缺陷。实验表明该算法能够自动满足规定的水印图像信噪比要求,水印具有良好的稳健性。

Sightlessness is one of the most basic requirements for invisible watermarks, its impersonal criterion is signal-to noise ratio of watermarked image. By this criterion, an absolutely adaptive gray watermark algorithm is pro posed based on DWT, that is to say, despite of different host images and watermarks, the algorithm is able to choose embedding intensity automatically with a dimension search and reaches the demanded signal--to--noise ratio of watermarked image, avoids the bug of choosing embedding intensity by experience or experiments. Experiments show that the algorithm is able to meet the PSNR requirements and performances of the proposed watermarking are good at robustness.