基于小波变换和混沌映射的自适应水印算法

提出的基于小波变换和混沌映射的自适应图像水印算法中水印由混沌序列生成,在宿主图像的低频系数中嵌入水印信息,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:该算法能够自适应地根据图像内容添加水印,对图像的平滑区进行的修改非常小,而对图像中抑制噪声能力较强的纹理和边缘区域修改较大,使用该算法嵌入的数字水印具有很好的隐蔽性、安全性及鲁棒性。

Image-adaptive watermarking algorithm based on chaos map and DWT

A robust watermark algorithm based on discrete wavelet transform and chaos map was proposed.In the algorithm,the watermark was produced by a chaotic sequence and embedded in the lowest band of the original image.Before the watermark was embedded,a correlation mask for every lowest coefficient was confirmed by the characteristic and tree structure relation of the wavelet coefficients.Then,the hided watermarking strength of every lowest coefficient was controlled by its corresponding mask.The experimental results show that the embedded digital watermarks with this proposed method are image-adaptive,invisible and security,it is more robust.So it is an effective method to protect copyright of digital image.