Optimization-Based Embedding for Wavelet-Domain Audio Watermarking

This work proposes a new blind digital audio watermarking system by using optimization-based modification on low-frequency amplitude of discrete wavelet transform (DWT). To modify the low-frequency amplitude under the best signal-to-noise ratio (SNR), the proposed embedding system minimizes the difference between the original and the embedded coefficients. Accordingly, an optimization-based embedding formula connecting the SNR and the embedding system is derived. The formula is then applied to embed the synchronization codes and the watermarks. Based on this formula, the number of DWT coefficients for embedding a binary bit can be increased to enhance the robustness without decreasing the audio quality. Consequently, the embedded audio has good quality and good robustness under high capacity. In addition, the system can extract the hidden data without the knowledge of original audio signal. Finally, the performance of the proposed watermarking method is tested. Experimental results indicate that the performance of proposed system is better than other DWT amplitude modification method.