基于小波变换的彩色图象数字水印算法

提出了一种基于离散小波变换（DWT）域的彩色图象序列加密数字水印新方法，算法选用了彩色图象RGB色彩空间的G分量嵌入水印，数字水印图象含有密钥信息，因此算法具有很好的安全性。同时利用人类视觉系统（HVS）的亮度掩蔽特性和纹理掩蔽特性，把低频分量根据局部纹理的强弱分成两类，将二值水印图象加密后自适应的嵌入到宿主图象的DWT域的低频分量中，从而很好的兼顾了水印的不可见性与鲁棒性。大量仿真结果表明本算法对于诸如JPEG压缩、高斯噪声干扰和图象剪切具有很好的鲁棒性。

A Color Image Digital Watermarking Algorithm Based on DWT

In this paper,an encrytped color image digital watermarking algorithm based on DWT domain is proposed.At first,we design a binary watermarking signal and encrypt it by a sequence based on logistic before it is embedded into G component of RGB color space in DWT domain,so algorithm has very good security.Then,by expoiting the visual masking and texture characteristics of Human Visual System(HVS) to ensure the self-adaptation,binary encrypted watermarking is embedded into the lower frequency cofficients of the orignal image in Discrete Wavelet Transform(DWT) domain,which are divided into two types by the diferent strength of local texture of image.The exprimental results show that the watermarking are invisible and robust against noise and commonly used image-processing methods such as JPEG,Guassian,cutting etc.