Improved speech enhancement with on-line signal and noise spectrum estimation

• Main Authors: Tsai-Kan Chien, 簡才淦
• Other Authors: 吳國光
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/52090318058622306894

碩士 === 國立中興大學 === 電機工程學系所 === 96 === ABSTRACT The thesis means how to reduce noise for noisy speech signal‚then received signal can approach transmitted clean signal. When reducing noise for speech enhancement‚it will still consider to reduce spectral distortion phenomenon. So the receiver clearly listens sentences that the transmitter wants to speak. This paper uses Tho-LMS method that reduces noise for noisy speech signal‚and gets on-line signal spectrum that transfers to frequency domain with Fourier transform. We use noise spectrum estimation methods to get noise energy spectrum, such as subtraction method‚non-speech pause method‚and minimum statistics method, that supply speech enhancement to reduce noise. Traditional speech enhancement methods like spectral subtraction and Wiener filter. The paper uses the other speech enhancement that is called Beta-order minimum mean square. After noise spectrum estimation we get frame signal-to-noise ratio,it can be calculated optimum Beta variable. And the noisy speech signal is directly multiplied the gain function that includes Beta variable. Finally, the enhanced speech signal transfers to time domain with inverse Fourier transform, and we use overlap and add to get reconstructed clean speech signal.