公开(公告)号：US06453289B1

公开(公告)日：2002-09-17

申请号：US09361015

申请日：1999-07-23

Applicant: Filiz Basbug Ertem ,  Srinivas Nandkumar ,  Kumar Swaminathan

Inventor： Filiz Basbug Ertem ,  Srinivas Nandkumar ,  Kumar Swaminathan

IPC: G10L2102

CPC classification number: G10L25/78 ,  G10L21/0208

Abstract: An improved noise reduction algorithm is provided, as well as a voice activity detector, for use in a voice communication system. The voice activity detector allows for a reliable estimate of noise and enhancement of noise reduction. The noise reduction algorithm and voice activity detector can be implemented integrally in an encoder or applied independently to speech coding application. The voice activity detector employs line spectral frequencies and enhanced input speech which has undergone noise reduction to generate a voice activity flag. The noise reduction algorithm employs a smooth gain function determined from a smoothed noise spectral estimate and smoothed input noisy speech spectra. The gain function is smoothed both across frequency and time in an adaptive manner based on the estimate of the signal-to-noise ratio. The gain function is used for spectral amplitude enhancement to obtain a reduced noise speech signal. Smoothing employs critical frequency bands corresponding to the human auditory system. Swirl reduction is performed to improve overall human perception of decoded speech.

Abstract translation: 提供了一种改进的降噪算法，以及用于语音通信系统中的语音活动检测器。 语音活动检测器允许噪声的可靠估计和噪声降低的增强。 噪声降低算法和语音活动检测器可以在编码器中一体地实现或独立地应用于语音编码应用。 语音活动检测器采用经过降噪的线谱频率和增强输入语音以产生语音活动标志。 噪声降低算法采用从平滑噪声谱估计和平滑输入噪声语音谱确定的平滑增益函数。 基于信噪比的估计，以自适应方式在频率和时间上平滑增益功能。 增益函数用于频谱振幅增强，以获得降噪噪声语音信号。 平滑采用对应于人类听觉系统的临界频带。 进行旋转减少以改善对解码语音的整体人感知。