A robust DWT-based blind data hiding algorithm
The watermark embedding strategy is one of factors that affect the robustness of the watermark. In this paper, a new embedding strategy based on the discrete wavelet transform (DWT) is proposed. Different from the existing schemes based on the DWT which have explicitly excluded LL subband coefficients from watermark embedding, we claim that watermarks should be embedded in the LL subband first, and then in high frequency subbands according to the visual significance of the subbands. We have compared the performance of our new embedding strategy with that of the commonly used ones, confirming the superiority of the proposed embedding strategy. Based on this strategy, a robust oblivious watermarking algorithm in the DWT domain is presented. It takes advantage of error correcting coding (ECC) and 2D interleaving techniques to lower the detection error probability. By taking a carefully designed measure in watermark bit embedding, watermarked images achieve a 2dB improvement in PSNR. The experimental results show that the watermark embedded with the proposed algorithm is robust and invisible.