Robust image watermarking in 3-D space using wavelet coefficients

This paper presents a robust image watermarking method based on geometric modeling. In this method, nine samples of the approximation coefficient of the image blocks are utilized to construct a plane in the 3-D space. We change the dihedral angle formed between the created plane and the x-y plane for data embedding. In order to preserve the imperceptibility of the watermark, geometrical computations are used to minimize the embedding distortion. Due to embedding in the dihedral angle between two planes, the proposed scheme has high robustness to gain attacks. Besides, by using the low frequency components of the image blocks for data embedding, high robustness against noise and compression attacks has been achieved. Experimental results confirm the validity of the theoretical analysis given in this paper and show the superiority of the method over similar techniques in this field.