Abstract: Concerning the drawbacks of relatively large location map and the quality decline of stego-images from excessive modulation to pixels of Tian's algorithm, a reversible data hiding algorithm for color images based on piecewise difference expansion was proposed. This algorithm used correlation of color components to decrease difference and disperse smaller expansion to two components, and used piecewise difference expansion and bit plane replacing to embed data information, and the quantity of un-expandable difference was decreased. Changeability of difference was used to locate unchangeable difference, so the payload capacity could be increased. The experimental results show that the payload capacity and the quality of stego-image are significantly improved, compared with other new or classical algorithms.

Key words: reversible data hiding, piecewise difference expansion, bit plane replacing, overflow location map, Prediction Error Difference Expansion (PEDE)

摘要： 针对Tian差值扩展技术存在过分修改像素值、定位图较大等缺点，提出一种基于分段差值扩展的彩色图像可逆数据隐藏算法。利用色彩分量之间的相关性减小差值，并将较小的差值扩展量分散到两个色彩分量中，采用分段差值扩展和位平面替换的方法嵌入数据，从而减少不可扩展差值的数量，提高定位图的压缩率，根据差值次低位平面的可改变性定位不可变差值，从而提高嵌入容量。提取端在提取信息后可根据需要无损地恢复原始图像。实验结果表明，该算法在保证图像质量的同时，嵌入容量有较大的提高。

关键词: 可逆数据隐藏, 分段差值扩展, 位平面替换, 溢出定位图, 预测误差差值扩展