基于图像小波树结构的数字水印算法

Digital Watermarking Algorithm Based on Wavelet Transform Tree Structure of Image

提出了一种基于小波变换和根据图像内容的自适应水印算法。该算法利用图像小波变换系数的树结构关系和各层小波系数的特点,对低频重要系数进行分类,并根据人类视觉特性,对不同类采用不同的嵌入方法。而且在水印提取过程中不需要原始图像,是一种盲水印算法。实验结果表明,该方法简单高效,可嵌入的数字水印信息容量大,而且通过与传统方法的比较,方法不可见性好,PSNR=52.28dB,对一般的图像处理和攻击如:JPEG压缩、滤波、加噪声、旋转、缩放等有很好的鲁棒性。

An adaptive watermarking algorithm was given based on wavelet transform and image-content. The algorithm used the tree structure of the coefficients of the wavelet transform of the image and the characteristic of coefficients of all layers to classify the important coefficients of the lowest frequency. According to different groups, the watermark was embed in different ways through the human visual system. Moreover no host image was needed in watermarking extraction, which was a blind waterrrfarking algorithm. Experimental results show that the method is simple and effective with high capacity of watermark. It has better imperceptibility than the former one, PSNR^52.28dB.And it is robust against normal image processing and kinds of attacks, for example JPEG compression, filtering, adding noise, rotating and zooming.