关键词: 语音增强, Turbo迭代, 谱减法, 小波包降噪, 多阈值

Abstract: Although self-iterative algorithm of Spectral Subtraction（SS） can improve signal-noise ratio，the level of speech distortion increases with the number of iterations.This paper proposes a new reinforced spectral subtraction algorithm that applies wavelet packet multi-thresholds de-noising in noisy subspace of noisy speech space based on Turbo iterative principle.The Turbo iterative processing is a technique in which self-iterative spectral subtraction is combined with wavelet packet multi-thresholds de-noising.Both component filters work cycled in signal subspace and noisy space respectively to extract speech information，each one takes some feedback information from the other filter as a priori condition.The simulation results show that this new algorithm converges within 10 iterations，and it achieves much better performance for the balance of noise reduction and speech distortion.

Key words: speech enhancement, Turbo iteration, spectral subtraction, wavelet packet de-noising, multi-thresholds