METHOD AND APPARATUS FOR NOISE SUPPRESSION, SMOOTHING A SPEECH SPECTRUM, EXTRACTING SPEECH FEATURES, SPEECH RECOGNITION AND TRAINING A SPEECH MODEL

摘要

The present invention provides a method and apparatus for noise suppression, smoothing a speech spectrum, extracting speech features, speech recognition and training a speech model. Said method of noise suppression is performed by minimum mean-square error estimation, wherein the confluent hyper-geometric function is approximated by a piece-wise linear function, which greatly decreases the computation load while maintains the noise-reduction performance. Moreover, to avoid producing the frequency components of extremely low energy, the present invention smoothes the speech spectrum both in time and frequency axis with geometric sequence weights after minimum mean-square error estimation. Moreover, the present invention balances noise suppression and speech distortion by adjusting the a priori signal-noise-rate.