Adaptive Speech Enhancement Method Based on Sparse Representation

现代语音通信系统中，大部分的语音信号往往受到背景噪声的干扰，在一定程度上降低了语音信息的可辨性和人耳的听觉舒适性，不利于后继的语音信号处理工作的开展。为了改善语音质量，语音增强技术应运而生，希望在尽可能不引入新噪声的前提下，抑制背景噪声对语音信息的负面影响，提高带噪语音的可辨性。 鉴于语音信号的稀疏先验性，本文基于稀疏表示框架实现对带噪语音的增强处理。通过对字典训练算法和目标优化函数的分析，分别研究了基于K-SVD（K-SingularValueDecomposition，K-奇异值分解）自适应稀疏字典的语音增强方法、基于CNMF（ConvolutionNonnegativeMatrixFa...In Modern voice communication system, most of the speech signal is often affected by background noise, which reduces the differentiability of speech information of the comfort of auditory in some degree, and influences the subsequent speech signal processing. In order to improve the quality of speech, speech enhancement technology arises at the historic moment, in which we hope inhibit the negativ...学位：工学硕士院系专业：信息科学与技术学院_电路与系统学号：2312012115287

Speaker-normalized sound representations in the human auditory cortex

The acoustic dimensions that distinguish speech sounds (like the vowel differences in “boot” and “boat”) also differentiate speakers’ voices. Therefore, listeners must normalize across speakers without losing linguistic information. Past behavioral work suggests an important role for auditory contrast enhancement in normalization: preceding context affects listeners’ perception of subsequent speech sounds. Here, using intracranial electrocorticography in humans, we investigate whether and how such context effects arise in auditory cortex. Participants identified speech sounds that were preceded by phrases from two different speakers whose voices differed along the same acoustic dimension as target words (the lowest resonance of the vocal tract). In every participant, target vowels evoke a speaker-dependent neural response that is consistent with the listener’s perception, and which follows from a contrast enhancement model. Auditory cortex processing thus displays a critical feature of normalization, allowing listeners to extract meaningful content from the voices of diverse speakers