A robust blind watermarking method using quantization of distance between wavelet coefficients

In this paper, we propose a robust blind watermarking algorithm based on quantization of distance between wavelet coefficients for copyright protection. We divide wavelet coefficients into some blocks and obtain the first, second, and third maximum coefficients in each block. Then we do quantization between the first, and second maximum coefficients according to binary watermark bits, which effectively makes watermark to be resist against attacks. Also, we need neither the original image nor watermark to extract the embedded watermark by using the block-based watermarking method. The algorithm as a watermarking system has appropriate performance duo to imperceptibility. In addition, experimental results also show that the proposed method is quite robust under either non-geometry or geometry attacks.