基于MCLT变换的音频数字水印技术

在网络与数字信息给人们带来方便的同时，也给人们带来了隐患：敏感信息可能轻易地被窃取、篡改、非法复制和传播等．信息的安全与保密显得越来越重要，信息安全已成为人们关心的焦点，也是当今信息领域的研究热点之一．提出了基于MCLT变换的谱弯折音频水印算法，利用谱弯折技术，通过调整MCLT变换的角频率，可将视觉可辨的二值图像嵌人音频之中，实现水印在整个频域嵌入，算法的最大优点是嵌入量较大．经实验验证，认为谱弯折方法对MP3压缩、重采样等的攻击相当脆弱，不具备鲁棒性，属半易碎型音频水印．

An Audio Digital Watermarking Algorithm Based on Modulated Complex Lapped Transform

With the development of multimedia technology and computer network, the distribution and transmission of digital media(e.g., image, text, audio and video) become very convenient. But rampant piracy, forgery and tamper is stunting the development of digital era. How to provide available method for copyright protection and information security has become a hot research area. Digital watermarking as a copyright protection technology is developed in this condition. Digital audio watermarking is especially challenging compared with digital video and image watermarking because the human auditory system (HAS) is far more sensitive than the human visual system(HVS). An audio watermarking algorithm based-on Modulated Complex Lapped Transform(MCLT) is proposed. Using spectrum-warping technique that shifts spectrum coefficients non-linearly, a significant binary image is embedded in audio by modulating MCLT's angle frequency. In order to improve the security, some pretreatments for watermark are carried through before it is embedded to audio, such as repeat coding and interleaver etc. The watermarking is embedded in all audio frequency domain, and embedding capability is high. The experimental results show that the spectrum-warping watermarking algorithm is of low robustness against MP3 compression, resampling and so on. It is a fragile watermarking algorithm.