通过修改JPEG图像块中的DCT系数, 提出一种新的稳健可逆信息隐藏方法. 遍历块中特定位置连续6个DCT系数的均值, 找出最接近0的均值进行嵌入. 由于连续DCT系数的均值接近0, 经过压缩操作不会有太大的变化, 因此所嵌入的秘密信息有一定的稳健性. 为了对抗攻击, 在嵌入秘密信息时, 通过比较并改变系数的大小, 将改变量分为两个等级进行自适应嵌入. 若含密图像未被压缩, 则不仅可以正确提取秘密信息, 而且可以恢复原始图像; 若含密图像已被压缩, 则只能正确提取秘密信息, 不能恢复原始图像. 实验结果表明, 在经过质量因子为85以上的压缩攻击后, 含密图像的视觉效果很好, 并且仍能正确提取秘密信息.
This paper proposes a robust reversible information hiding scheme based on DCT coefficients modification in JPEG images. The mean of six consecutive DCT coefficients close to zero is found. Since the mean of these six coefficients changes very little after compression, robustness can be achieved. The coefficients are modified to embed information using two different levels to resist attack. If the stego-image is not recompressed, the secret information can be correctly extracted, and the original image can be recovered. If the stego-image is recompressed, the secret information is still extractable without error, but the original image cannot be recovered. Experimental results show that the proposed scheme is effective after recompression attack with Q = 85 or above, and the stego-images have good visual quality.
[1] Tian J. Reversible data embedding using a difference expansion [J]. IEEE Transactions on Circuits and Systems for Video Technology, 2003, 13(8): 890-896.
[2] Celik M U, Sharma G, Tekalp A M, et al. Lossless generalized-LSB data embedding [J]. IEEE Transactions on Image Processing, 2005, 4(2): 253-266.
[3] Ni Z C, Shi Y Q, Ansari N, et al. Reversible data hiding [J]. IEEE Transactions on Circuits and Systems for Video Technology, 2006, 16(3): 354-362.
[4] Goljan M, Fridrich J, Du R. Distortion-free data embedding [C]//Information Hiding. 2001: 27-41.
[5] De Vleeschouwer D, Delaigle J F, Macq B. Circular interpretation of bijective transformations in lossless watermarking for media asset management [J]. IEEE Transactions on
Multimedia, 2003, 5(1): 97-105.
[6] Ni Z C, Shi Y Q, Ansari N, et al. Robust lossless image data hiding [C]//IEEE International Conference on Multimedia and Expo. 2004: 2199-2202.
[7] Ni Z C, Shi Y Q, Ansari N, et al. Robust lossless image data hiding designed for semi-fragile image authentication [J]. IEEE Transactions on Circuits and Systems for Video Technology, 2008, 18(4): 497-509.
[8] Zou D, Shi Y Q, Ni Z C. A semi-fragile lossless digital watermarking scheme based on integer wavelet transform [C]//IEEE 6th Workshop on Multimedia Signal Processing. 2004: 195-198.
[9] Zou D, Shi Y Q, Ni Z C, et al. A semi-fragile lossless digital watermarking scheme based on integer wavelet transform [J]. IEEE Transactions on Circuits Systems for Video Technology, 2006, 16(10): 1294-1300.
[10] Kim K S, Lee M J, Suh Y H, et al. Robust lossless data hiding based on block gravity center for selective authentication [C]//IEEE International Conference on Multimedia and Expo. 2009: 1022-1025.
