基于错误控制编码的差值扩展可逆数字水印

Reversible Digital Watermarking Based on Error Control Coding Using Difference Expansion

可逆数字水印能在水印提取后将含印载体恢复到无失真的原始状态。Tian的基于差值扩展隐藏算法是目前容量最高但含印载体质量偏低的可逆隐藏算法。针对Tian中过度修改像素对值造成含印图像质量不必要下降问题,该文提出了基于错误控制编码的差值扩展可逆数字水印算法。该算法将像素对仅分为I,II两类。嵌入、提取及恢复过程对称,实现相对简单,含印图像质量在容载较低时得到很大提高。

Reversible digital watermarking can reverse the marked media to the original state without any distortions after the hidden data is retrieved. Tian＇s reversible data hiding algorithm using difference expansion is the algorithm whose capacity is the highest among all the reported examples, but its quality of watermarked carrier images is lower relatively. To avoid the unnecessary quality decline of watermarked images from excessive modulation to pixel pairs, this paper proposes an ECC based reversible digital watermarking difference expansion. The algorithm distinguishes pixel pairs into only two types, i.e. Type I and Type II. Its embedding, extraction, and recovery processes are symmetrical. The computation of the proposed algorithm is quite simple and execution time is rather short. The quality of watermarked images is improved largely, especially when the level of its payload is low.