摘要
针对密文域可逆信息隐藏(reversible data hiding in encrypted images,RDHEI)算法存在像素利用率低和嵌入容量小等问题,本文提出了一种基于邻接差值和块分类(adjacency difference and block classification,ADBC)的RDHEI算法.首先,充分利用原始图像的空间相关性,通过计算得到邻接差值图像,根据图像块的最大值实现初次块分类操作;其次,对初次分类中不可嵌入的图像块,采用中值边缘预测器来预测像素,完成第二次块分类;然后,执行图像加密;最后,通过位替换,将辅助信息和秘密信息嵌入加密图像.实验结果表明,本文算法相较于现有算法,在BOSS base、BOWS-2和UCID3个数据集上的平均嵌入率(embedding rate,ER)分别提高0.06 bpp、0.01 bpp和0.15 bpp以上,能够获得较高的嵌入容量.
Abstract
The existing reversible data hiding in encrypted image(RDHEI)algorithm has the problems of poor utilization rate of pixels,and small embedding capacity.Addressing such issues,an RDHEI algorithm based on adjacency difference and block classification(ADBC)scheme is proposed.Firstly,the spatial correlation of the original image is fully utilised to obtain the adjacency difference image by calculation,and the initial block classification operation is realised according to the maximum value of the image block;secondly,the median edge predictor is used to predict the pixels for the non-embeddable image blocks in the initial classification to complete the second block classification;then,the image encryption is executed;finally,the auxiliary data and secret data are embedded in the encrypted image by bit substitution.The experimental results show that the average embedding rate(ER)of algorithm in this paper is over 0.06 bpp,0.01 bpp and 0.15 bpp higher on the BOSS base,BOWS-2 and UCID datasets respectively compared with the existing algorithms.
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