基于高阶位平面冗余的可逆信息隐藏方法

Reversible data hiding method based on high-order bit-plane redundancy

针对现有加密图像可逆信息隐藏(RDHEI)方法存在的隐藏容量低、解密标记图像质量差的问题,提出了一种新的基于高阶位平面冗余的RDHEI方法。首先,通过Logistic映射对原始图像进行分块加密,并保留块内像素高阶位平面的冗余;其次,依据块内高阶位和低阶位个数是否相同的规则将加密后的图像块分为可嵌入块和不可嵌入块,并在可嵌入块中使用像素低阶位的值替换对应的高阶位值,从而实现高阶位平面冗余向低阶位平面的转移;最后,利用块内低阶位平面中腾出的嵌入空间来嵌入机密信息。在这之后,接收者利用密钥实现数据提取、图像解密和图像无损恢复的操作。在使用USC-SIPI标准图像库中的6幅图像进行的仿真实验中,在高阶位平面数等于3时,所提方法的图像的平均嵌入率为1.73 bpp,直接解密后的标记图像的平均峰值信噪比(PSNR)为47.20 dB。实验结果表明,该方法不仅提高了加密图像的信息嵌入量,而且提高了直接解密后的标记图像的PSNR值。

Focused on the problems of low hiding capacity and poor quality of decrypted labeled images in the existing Reversible Data Hiding in Encrypted Image(RDHEI)methods,a new RDHEI method based on high-order bit-plane redundancy was proposed.Firstly,the original image was encrypted in blocks by Logistic mapping,and the redundancy of the high-order bit-plane of the pixels in the blocks was retained.Secondly,according to the rule of whether the numbers of high-order bits and low-order bits in the block were the same,the encrypted image blocks were divided into embeddable blocks and non-embeddedable blocks,and the low-order bit value of the pixel was replaced with the corresponding high-order bit value in the embeddable blocks,so that the high-order bit-plane redundancy was transferred to the low-order bit-plane.Finally,the confidential information was embedded in the embedding space vacated in the inner-block low-order bit-plane.After that,the operations of data extraction,image decryption and image lossless recovery were realized by the receiver with the key.In the simulation experiments on 6 images in the USC-SIPI standard image library,when the number of high-order bit-planes is equal to 3,the proposed method has the average embedding rate of the image of 1.73 bpp,and the average Peak Signal-to-Noise Ratio(PSNR)of the marked image after direct decryption reaches 47.20 dB.The experimental results show that the proposed method not only increases the information embedding capacity of the encrypted image,but also increases the PSNR value of the labeled image after direct decryption.