Study Of Speech Enhancement Algorithm Based On The DCT-RLS Principle

Speech enhancement is one of the most important speech processing technology,which is widely used in speech recognition, speech coding and speech synthesis. Thepurpose of the speech enhancement is as far as possible to extract the clean speechsignal from the noisy signal. Because of the diversity of the noise and the complexityof speech signal, the corresponding speech enhancement algorithms are different indifferent noise environment.According to different treatment means of the noisy speech signal, speechenhancement algorithms can be divided into the time domain algorithms andtransform domain algorithms. The algorithms of the time domain directly processspeech signal in the time field, including adaptive denoising algorithm, the algorithmbased on speech production model, etc. The algorithms of the transform domainanalysis and process the speech signal in transform fields, which commonly use DFT,DCT and KLT transform. The representative algorithms include spectral subtractionmethod, sub-space method, the short-term spectral estimation algorithm and thewavelet transformation algorithm, etc.The adaptive algorithm deals with the known input data to seek for an optimalfilter which can minimize the mean square error between the output of the filter andthe needs of the signals. The adaptive algorithms (such as Minimum Mean Squarealgorithm and the Least Square algorithm) usually get the estimation of the filterparameters or the approximation of the optimal filter by recurring the known data. Wecan get the relevant speech enhancement algorithms by using these algorithms inspeech signal field. These algorithms can eliminate the noise of the knownobservation signal effectively. Through computer simulation experiment, we analyze,discuss and get the characteristics and the performance of RLS speech enhancementalgorithm and LMS speech enhancement algorithm. The simulation results show that,RLS speech enhancement algorithm has higher signal-to-noise ratio, and bettercapability in inhibiting signal distortion.The DCT transform has the merits of energy concentration, no need estimatingthe phase of the speech signal. The speech enhancement algorithm based on DCTobtains the ideal effect in keeping low computing complexity. The classical discretecosine transform of speech enhancement algorithm is researched in this paper. Sincethe relevance and short-term stationary characteristic of the speech signal, thecomponents of DCT in continuous time have strong correlation. According to thecorrelation of the components and combining with the theory of minimum mean square error of RLS algorithm, we research on speech enhancement algorithm basedon the DCT-RLS principle and obtain the optimal estimation of clean speech. Thesimulation experiment results show that the algorithm has better performance andhigher Signal-to-Noise ratio of the output speech.