CAJ | 학술논문

提出一种基于小波变换的数字水印两次嵌入算法。该算法把同一水印两次分别嵌入到高频子图和低频子图中以达到透明性和鲁棒性的兼顾。首先用3个高频子图小波域系数值找出强边缘，把除去强边缘的纹理区和平滑区作为可嵌入区域，然后用可嵌入区域内相邻系数值比较法嵌入二值水印。提取时，从两个子图中分别检测出水印，并求其平均值就得到了最终提取的水印。实验表明，该算法既有良好的透明性，而且对噪声、JPEG压缩、剪切、修改图像内容等常见攻击都具有较高的鲁棒性。
제출일충기우소파변환적수자수인량차감입산법。해산법파동일수인량차분별감입도고빈자도화저빈자도중이체도투명성화로봉성적겸고。수선용3개고빈자도소파역계수치조출강변연，파제거강변연적문리구화평활구작위가감입구역，연후용가감입구역내상린계수치비교법감입이치수인。제취시，종량개자도중분별검측출수인，병구기평균치취득도료최종제취적수인。실험표명，해산법기유량호적투명성，이차대조성、JPEG압축、전절、수개도상내용등상견공격도구유교고적로봉성。
A digital watermarking algorithm based on discrete wavelet transform (DWT) is proposed in the paper by the watermark being embedded twice in the high frequency sub-image and the low frequency sub-image respectively for bal-ancing transparency and robustness of the stego-image. Firstly, the strong edges is found by comparing wavelet coeffi-cients values of three high frequency sub-images, and then the regions except the strong edges are as the embeddable regions which include the texture area and the smooth area. Then the watermark was embedded in the two sub-images by exchanging the adjacent wavelet coefficients in the regions. When extracting, the watermark was got by averaging the two watermarks which had been extracted form the two sub-images. Experiments show that the algorithm is not only transparent, but also robust to noise, JPEG compression, cut, modify content, and other common attacks.