基于非线性语音谱分析的单通道语音增强研究

项目名称： 基于非线性语音谱分析的单通道语音增强研究

项目编号： No.61302126

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 无线电电子学、电信技术

项目作者： 王杰

作者单位： 广州大学

项目金额： 23万元

中文摘要： 单通道语音增强面临两个根本性问题：一是谱估计方差既可能产生"音乐噪声"，也可能造成语音失真；二是当前的噪声估计算法难以跟踪非平稳态噪声，低估噪声会导致大量的噪声残留。针对这两个根本性问题，我们验证了倒谱后处理能在不增加语音失真的情况下抑制部分非平稳态噪声，本项目将进一步开展基于非线性语音谱分析的单通道语音增强研究。相比于基于线性谱估计的传统方法，采用基于倒谱分析和重分配谱图的非线性语音谱估计具有如下优势：首先，利用倒谱分析可以将噪声从语音信号分离出来；其次，利用重分配谱图可以充分利用语音帧间和频间相关性。本项目拟对语音倒谱进行理论研究，研究其统计特性，该理论研究成果既应用于提高噪声跟踪性能，又应用于后处理抑制残留的非平稳态噪声。同时，进一步对重分配谱图进行理论研究，利用语音帧间和频间相关性抑制非平稳态噪声。该研究的理论成果将解决实际环境中的单通道语音增强问题，为实用化扫清障碍。

中文关键词： 语音增强；谐波重构；倒谱；重分配图谱；非线性谱

英文摘要： There are two basic prolems existed in the state-of-the-art single-channel speech enhancement algorithms. First, the bias and the variance of the spectral estimator may introduce both musical noise and audible speech distortion. Second, the existing noise estimators could not track non-stationary noise in a fast way, which may result in greatly reducing the amount of noise reduction. To solve these two problems, we have proved that some non-stationary noise components could be suppressed without introducing audible speech disortion by using cepstrum-based postprocessing scheme, where this project will further study non-linear speech spectrum analysis-based single-channel speech enhancement. Compared with the conventional single-channel speech enhancement, the proposed method that uses both cepstral analysis and reassigned spectrogram has at least two advantages. First, the noise components can be separated from the speech components by using cepstral analysis. Second, we can fully utilize both the temporal correlation between successive speech frames and the frequency correlation between adjacent bands with the help of reassigned spectrogram. This project will study theoretical propertis of cepstral coefficients of the speech, where the thoeretical results can be used to improve the noise tracking capablity and

英文关键词： speech enhancement；harmonic regeneration；cepstrum；reassigned spectrogram；non-linear spectrum