基于小波变换的图像水印嵌入方法

基于小波变换的数字水印技术是当前的一个研究热点。该文提出了将随机序列嵌入到小波图像的低频系数的方法。但从视觉效果的考虑,在小波图像的低频系数嵌入水印会降低图像质量。为克服这个问题,该文将水印嵌入到视觉不敏感的位置,并且根据视觉系统纹理掩蔽特性,将不同强度的水印分量嵌入到不同的小波系数中。实验结果表明水印是不可见的,对JPEG有损压缩、中值滤波、噪声干扰等有较强的鲁棒性。

Image Watermarking Based on Wavelet Transform

The watermark in g technology based on wavelet transform is the most active topic in digital wate rmarking.In this paper,a watermarking method is proposed that embeds a random sequence(watermarks)into the lower frequency subband based on the wavelet coef ficient distribution.But the subband is not suitable for embedding because of severe visual degradation.In order to overcome the degradation problem,water marks are embedded into visually insensitive locations.By exploiting and depen ding on the feature of visual masking of human vision system,watermark componen ts with different strength are embedded into different wavelet coefficients.T he experimental results show that the watermark is perceptually invisible and th e proposed scheme is robust to some image processing such as loss JPEG defecti ve compression,median filtering,noise.