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    JPEG图像多域可逆信息隐藏及载荷分配算法

    Multi-Domain Reversible Data Hiding in JPEG Images and Payload Distribution Algorithm

    • 摘要: 信息隐藏技术通过修改数字媒体信号嵌入附加信息而不影响媒体本身的使用价值;可逆信息隐藏不仅可以隐藏并提取附加信息,还可以无失真地恢复载体,是当前研究热点.针对应用最广泛的图像格式JPEG(joint photographic experts group),其可逆信息隐藏方法可分2类:1)离散余弦变换(discrete cosine transform, DCT)系数域修改,会导致文件扩展和视觉质量失真;2)熵编码域修改,生成的载密图像与原始图像相比无信号失真,但载荷有限且载荷越高往往文件扩展越严重.针对这2类方法存在的问题,设计了一种JPEG图像多域可逆信息隐藏算法,同时考虑DCT系数域修改和熵编码域修改来嵌入附加信息.由于2个域的修改对视觉质量失真和文件扩展的影响不同,因此研究重点在于载荷的合理分配.首先分析了在熵编码域嵌入信息时引起文件扩展的原因;然后据此设计基于VLC频率直方图的载荷分配算法以最小化文件扩展和视觉质量失真.实验结果表明:所提算法在文件扩展和视觉质量方面明显优于现有的方法.

       

      Abstract: Data hiding technology embeds additional data by modifying the digital media signal and does not affect the use value of the media itself. Reversible data hiding can not only hide additional data and extract additional data, but also recover the original image without distortion, so it is the research focuses currently. Because JPEG is the most widely used image format, reversible data hiding methods can be divided into two categories: the first one embeds additional data by modifying the DCT coefficients domain, which results in file-size expansion and visual quality distortion. The second one modifies the entropy coding domain, and the encrypted image generated by this method has no signal distortion compared with the original image, but the payload is limited, and the higher the payload is, the larger the file expansion is. To mitigate the problems existing in these two kinds of methods above, a multi-domain reversible data hiding algorithm for JPEG images is designed, which embeds the additional data by modifying the DCT coefficients domain and the entropy coding domain. Since two domains have different effects on visual quality distortion and file expansion, this paper focuses on distributing the payload reasonably. In this paper, the reason of file expansion is analyzed firstly when embedding the additional data in entropy coding domain, then a payload distribution algorithm based on VLC frequency histogram is designed to minimize file expansion and visual quality distortion. Experimental results demonstrate that the proposed algorithm significantly outperforms state-of-the-arts in file size expansion and visual quality.

       

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