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 among 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 quantize the first and second maximum coefficients according to binary watermark bits. Using the block-based watermarking, we can extract the watermark without using the original image or watermark. The algorithm as a watermarking system has appropriate performance due to imperceptibility. In addition, experimental results also show that the proposed method is quite robust under either non-geometry or geometry attacks.