基于小波变换的图像自适应水印

Image-adptive watermark based on wavelet transform

提出了一种基于小波变换的图像自适应水印嵌入方法.此方法对原始图像进行小波分解,在每一个低频系数中嵌入一位水印信息,嵌入时根据低频逼近系数和高频系数的特点以及树结构关系,给每一个低频系数确定一个相关掩蔽参数,并用此参数控制其对应低频系数嵌入水印时的相对修改强度.实验表明:使用该方法嵌入的数字水印具有很好的隐蔽性,感觉不到对原始图像的影响.同时,嵌入的数字水印具有较理想的鲁棒性,常规的图像处理方法对其影响甚弱.

In this paper,an embedding method of imageadptive watermark based on wavelet transform is proposed. With this method,the original image is decomposed by wavelet transform, and a bit of watermark information is embedded in every lowest approximation coefficient.Before the watermark is embedded,a correlation mask for every lowest cofficient is confirmed by the characteristic and tree structure ralation of the wavelet coefficients.Then, the modified value of every lowest coefficient is controlled by its corresponding mask.The experimental results show that the embedded digital watermarks with this proposed method are invisible and robust enough against the commonly used image processing techniques.