后置感知滤波的多带语音增强方法研究

【作者】 李少伟；

【导师】 裴承鸣；

【作者基本信息】 西北工业大学 ， 信号与信息处理， 2006， 硕士

【摘要】 语音增强是语音信号处理的主要分支之一。在已有的各种增强算法中,谱减法因其物理意义最明确,计算量小,效果明显等优势得到相当广泛的应用。但是该方法存在的明显不足是会在听觉上形成残留音乐噪声。为此,在提高信噪比和尽量减少语音失真的前提下如何抑制音乐噪声就成为该领域关注的重点。 本文在深入研究谱减法和人耳听觉感知理论的基础上,结合人耳的听觉掩蔽效应和噪声特性,提出一种改进的谱减法—后置感知滤波的迭代多带谱减法。该方法采用迭代结构,针对实际噪声对语音谱的影响的不均匀性,通过在不同的频带设置不同的噪声过减因子,应用感知滤波器来完成对语音的平滑处理。 基于Matlab实现了整个增强算法,并针对不同信噪比的带噪语音进行了仿真实验,然后将其作为前端处理用在一个说话人识别系统中。实验结果表明,本文提出的方法在改善信噪比的同时大幅度降低了音乐噪声,总体上提高了语音质量以及识别系统的识别率。更多还原

【Abstract】 Speech enhancement is a main branch of speech processing. Among the methods of speech enhancement, spectral subtraction is popularly used because of its minimal complexity and relative ease in implementation. However, a specific disturbance called "musical noise" is introduced by using the method. Therefore, a great deal of attention is attracted to find out the best tradeoff between speech distortion and noise reduction.Based on the deep investigation of the theory of auditory perception, a modified spectral subtraction is presented in this thesis, which is named Iterative Multi-band spectral subtraction with perceptual post-filtering ( Pf-IMBSS ). An iterative structure is adopted in the approach. Due to the ununiformity affection of colored noise over the entire spectrum, speech is processed into frequency bands and spectral subtraction is performed independently on each band using band-specific over-subtraction factors. Finally, the speech signal is smoothed with a perceptual post-filter.The numerical specifics of Pf-IMBSS is investigated using noisy speech with different SNR. The algorithm proposed is then used in a speaker recognition system for preprocessing. The experiment results indicate that the musical noise can be consumedly suppressed, and the speech quality and the robustness of the recognizer are also guaranteed.The related software is completed under Matlab.更多还原