基于频段选择的JPEG图像可逆信息隐藏

Reversible Data Hiding Based on Frequency Selection in JPEG Images

通过研究分析联合图像专家小组(joint photographic experts group,JPEG)图像离散余弦变换(discrete Cosine transform,DCT)系数的编码方式以及各频段DCT系数分布与其编码尺寸间的关系,发现利用中高频段DCT系数进行可逆信息隐藏对图像编码效率的影响更小.为此,考虑将JPEG图像DCT系数按频段组合,使相邻子块同一频段区间的DCT系数构成一组系数集合,并优先选择0系数较多的集合以嵌入信息.实验结果证明,所提出的基于频段选择的JPEG图像可逆信息隐藏算法能够大大降低因信息嵌入而引起的图像存储空间的增加,同时还能较好地保持图像视觉质量.

In this paper, by studying the encoding method of the discrete cosine transform （DCT） coefficients of joint photographic experts group （JPEG） image, and analyzing the relationship between the statistical properties of the DCT coefficients and coding length, we find that hiding data into DCT coefficients belonging to the mid-and-high frequency bands will lead to less file size increment. Therefore, we propose a novel reversible data hiding （RDH） method based on the frequency selection strategy, in which the DCT coefficients of cover image are classified into different groups based on their frequency bands, and the DCT coefficients of adjacent blocks beIonging to the same frequency band are classified into the same group. Thereafter, those groups with more zero coefficients are chosen pref- erentially for reversible data hiding. Experimental results demonstrate that the proposed RDH method can not only lessen the file size increase introduced by data hiding greatly, but also perverse the image visual quality well.