A Color Image Watermarking Algorithm Based on 3D-DCT
Cheng Wei · Dianzi xuebao · 2001
In this paper,an adaptive color image watermarking algorithm based on 3D DCT(Three Dimensional Discrete Cosine Transform) is proposed.The algorithm demonstrates that 3D DCT outperforms 2D DCT in terms of energy concentration.Since the 3D DCT coefficients of a color image have larger magnitudes than that of the 2D DCT coefficients,the 3D DCT coefficients have larger perceptual capacity and then allow to embed stronger watermark signal.Based on 3D DCT,we propose to change the watermark strength adaptively by taking account of the perceptual feature of human visual system.The experimental results show that the proposed algorithm can trade off the conflict of transparency and robustness of invisible watermark well,the thus generated watermark can withstand under the common attacks,such as JPEG compression,additive noise,image filtering,color and luminance/contrast alteration very well.