Blind Image Watermarking Using Wavelet Coefficient Distance

In this paper a robust digital image watermarking algorithm proposed in wavelet transform domain. At first, the original image is decomposed into ten sub-bands by the 3-level wavelet transform. Then, the values of wavelet coefficients in HL3 are quantized. For embedding watermark bits, trees of wavelet coefficients are used. In each tree, the distance between the average of four wavelet coefficients in HL2 and their corresponding HL3 coefficient determines how HL3 coefficient is quantized. The experimental results show that the proposed algorithm has a good resistance against to common attacks, especially JPEG compression; moreover it outperforms previous methods in the most situations.