Watermarking Techniques For Digital Audio Based On Complex Cepstrum Transform

Along with digital techniques and internet, people can copy and transmit all kinds of digital audio media. It is beneficial to our daily life but brings to the problem of ownership protection. As a solution, digital audio watermarking is an effective method to solve the problem. A deep research of digital audio watermarking technology based on complex cepstrum transform is done in this paper. The main research efforts are as followed:A new blind watermark algorithm in cepstrum domain based on quantization is proposed, which uses the characteristics of complex cepstrum transform, and embeds watermark by quantizing mean of complex cepstrum coefficients. The watermarks can be extracted without the original digital audio signal. The experimental result shows that the embedded watermark is imperceptibility and robust to many common attacks, such as noise adding, re-sampling, low pass filtering, re-quantization and lossy compression and so on.The paper also proposes an adaptive audio watermark algorithm based on complex cepstrum transform. Watermark is embedded by dividing original audio signal into several segments and using masking of human auditory system (HAS) and the characteristics of complex cepstrum transform. The watermark can be embedded adaptively into the digital audio signals in the watermarking algorithm. It is a blind algorithm and the extracted watermark is without the original digital audio signal. The algorithm is not only imperceptibility and robust to many common attacks, such as noise adding, re-sampling, low pass filtering, re-quantization and lossy compression and so on.Compared with an audio digital watermarking algorithm based on wavelet transform and cepstrum transform in the references, the correlation is improved significantly.An audio watermark algorithm with self-synchronization based on complex cepstrum domain is proposed, which uses the characteristics of complex cepstrum transform. Synchronization code is embedded into audio with the watermark. Extract efficiency of synchronous signal are improved significantly and embedded watermark is robust to some common attcacks, such as noise adding, re-sampling, low pass filtering, re-quantization and lossy compression and so on.