The research of intelligent speech recognition technology has been going on for a long time. However
due to the characteristics of variability
instantness
continuity and dynamic of the speech signal itself
the identification of the speech still has some difficulties when the machine is put in different environments
especially in the noisy environment. In order to improve the recognition accuracy of the noisy speech signal
a commonly used noise estimation algorithm was studied
which was based on the time-averaged algorithm of posterior signal noise ratio. And an improved algorithm of the smoothing factor was brought up on the basis of the previous algorithm. The voice activity detection algorithm and the above two algorithms were simulated under different input signal-noise ratios. The comparative analysis of the operation results shows that the improved algorithm can improve the output segment SNR by 2.1 dB compared with the voice activity detection algorithm
and it can also improve the output segment SNR by 0.5 dB compared with the original time recursive average algorithm. It is indicated that the improved algorithm can effectively improve the quality and intelligibility of the speech signal at low input SNR.
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references
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