Abstract:

This paper presents a novel steganographic method in Discrete Cosine Transform（DCT） domain.In order to improve the embedding capacity of a cover-image while maintaining the stego-image quality acceptable，the DCT blocks of a cover-image are classified into three classes based on Human Visual System（HVS） characteristics and fuzzy theory，and then the number of bits to be embedded in each quantized DCT coefficient of a DCT block is varied with the type of the block.The experimental results show that the proposed method performs better than the fixed-length Least-Significant-Bits（LSBs） substitution method in DCT domain in terms of message capacity and image quality.Besides，the embedding data can be extracted from the stego-image without referencing to the original cover-image.

Key words: Steganography, Discrete Cosine Transform（DCT）, Human Visual System（HVS）, fuzzy classification

摘要： 提出了一种在图像DCT域内的信息隐藏方法。为了在保证隐秘图像视觉质量可以接受的前提下，有效提高载体图像的信息隐藏量，首先根据HVS特征和模糊理论将载体图像的各个DCT子块分为三类，然后根据DCT子块的类型不同，自适应变化嵌入每个DCT系数的秘密信息的位数。实验结果表明：该文方法在图像质量和信息嵌入量方面，都优于DCT域内固定嵌入位数的信息隐藏方法。此外，在秘密信息提取时，该文算法不需要参考原始载体图像，实现了提取信息的盲检测。

关键词: 信息隐藏, DCT, HVS, 模糊分类