CAJ | 학술논문

为克服现有压缩域水印算法图像质量或鲁棒性较差的缺点，提出了一种基于自适应有序抖动块截断编码的鲁棒水印算法。首先，利用图像的信息熵和方差自适应地将图像按四叉树分解为平滑块、纹理块和边缘块，再对不同大小的分块进行编码；然后，利用自适应有序抖动块截断编码得到的位平面，通过调整位平面水印嵌入窗口内元素的奇偶和，实现水印嵌入；最后，通过位平面中元素的奇偶和与投票策略来实现水印的盲提取。实验结果表明，与同类算法相比，该算法能够在取得较低压缩率的同时，获得良好的图像质量；并且有较高且灵活的水印嵌入容量；同时能够抵抗各种常见攻击，尤其对椒盐噪声、亮度调整、对比度调整、旋转、剪切攻击有很强的鲁棒性。
위극복현유압축역수인산법도상질량혹로봉성교차적결점，제출료일충기우자괄응유서두동괴절단편마적로봉수인산법。수선，이용도상적신식적화방차자괄응지장도상안사차수분해위평활괴、문리괴화변연괴，재대불동대소적분괴진행편마；연후，이용자괄응유서두동괴절단편마득도적위평면，통과조정위평면수인감입창구내원소적기우화，실현수인감입；최후，통과위평면중원소적기우화여투표책략래실현수인적맹제취。실험결과표명，여동류산법상비，해산법능구재취득교저압축솔적동시，획득량호적도상질량；병차유교고차령활적수인감입용량；동시능구저항각충상견공격，우기대초염조성、량도조정、대비도조정、선전、전절공격유흔강적로봉성。
To overcome the shortcomings of bad image quality or poor robustness of the current methods, a robust watermarking method based on adaptive order dither block truncation coding is proposed.Firstly, the image is adaptively divided into smooth regions,texture regions and edge regions using a quadtree segmentation,according to the information entropy and the variance.After that,these blocks are coded separately.Secondly,we exploit the bit plane obtained from adaptive order dither block truncation coding, and embed the watermark by changing the parity sum of the pixels within a window in the bit plane.Lastly, the watermark is retrieved with the parity sum and the majority voting strategy,not referring to the original image.The experimental results indicate that compared with the similar algorithm,the proposed method can achieve good image quality with a low compression rate,a high watermark rate and watermark rate flexibility.Moreover,it is robust to common attacks,especially to Salt & Pepper noising,brightness adj ustment,contrast adj ustment,rotating and cropping attacks.