【作者】 刘悦；

【导师】 许红梅；

【作者基本信息】 长春理工大学 ， 电路与系统， 2009， 硕士

【摘要】 针对现有的麦克风阵列语音增强方法大多数建立在远场信号模型上,在实际应用环境中如小型会议室语音获取,车内免提电话等,假设的远场模型并不成立。因此本文进行近场麦克风阵列语音增强方法研究。本文首先根据近场声源传播特点,通过距离差的方法减小位于远场的混响和噪声对语音的影响。采用近场的距离和方位补偿技术实现近场波束形成,准确得到近场期望信号的波束。其次研究近场自适应波束形成方法,提出一种NLMS算法的改进方法,并进行仿真比较,结果分析获得较好的性能。最后研究远场麦克风阵列语音增强方法,运用过采样余弦调制的子带技术,提出一种基于近场麦克风阵列语音增强方法,实验结果表明,近场波束形成语音增强方法改善了近场声学环境下的语音信号质量。更多还原

【Abstract】 To the most of microphone array processing approaches are based on far-field models. However, the far-field assumption may not hold in practical applications such as speech acquisition with microphone arrays in small rooms or hands-free mobile telephone in automobiles. This thesis focuses on microphone array speech enhancement approaches which are based on near-field model.In this paper, firstly, we based on characteristic of acoustic propagation about near-field source, according the method by difference distance to reduce the impact of reverberation and noise which is located in the far-field on the voice. To achieve near-field beamforming and accurate expectations of near-field, using near-field distance and azimuth compensations technique. Secondly, researching on beamforming methods of Near-field based on far-field beamforming algorithm, then propose an improved method of NLMS algorithm, the simulation prove that the new algorithm have obtained better performance. At last, study far-field microphone array speech enhancement method using of oversampled cosine-modulates subband technology. Propose a microphone array speech enhancement method based on near-field beamforming is presented in the paper. Simulation results demonstrate that the proposed method exhibits a better noise reduction performance than other methods.更多还原