| In this thesis, the single microphone speech quality enhancement algorithm in high noise environments is studied.;There are two parts in this thesis. In the first part, algorithms of reducing broadband stochastic noise are discussed. A main drawback of spectral-estimation-based algorithms, "musical noises", is presented and analyzed. To reduce musical noise, a novel method, Two-Dimensional Spectrogram Enhancement algorithm, is proposed. Then, a new speech quality enhancement scheme is implemented by combining the proposed algorithm with the MMSE-STSA method. SNR and Perceptual Evaluation of Speech Quality (PESQ) evaluations show that the proposed method is superior to two traditional algorithms.;In the second part, algorithms of removing impulsive interference are discussed. A new method using nonlinear filtering and forward-backward linear prediction is introduced. Simulation results of observation of waveforms and evaluation of PESQ show that this method can effectively reduce impulsive interference and improve speech quality. |
