This paper proposes a speech enhancement method using the multi-scales and multi-thresholds of the auditory perception wavelet transform, which is suitable for a low SNR (signal to noise ratio) environment. This method achieves the goal of noise reduction according to the threshold processing of the human ear's auditory masking effect on the auditory perception wavelet transform parameters of a speech signal. At the same time, in order to prevent high frequency loss during the process of noise suppression, we first make a voicing decision based on the speech signals. Afterwards, we process the unvoiced sound segment and the voiced sound segment according to the different thresholds and different judgments. Lastly, we perform objective and subjective tests on the enhanced speech. The results show that, compared to other spectral subtractions, our method keeps the components of unvoiced sound intact, while it suppresses the residual noise and the background noise. Thus, the enhanced speech has better clarity and intelligibility.
The construction process of the tunnel ground deformation regularity of surrounding rock, stability, deformation control of tunnel surface based on the requirements, combined with the characteristics of shallow tunnel with large-span. Used three-dimensional numerical simulation software, established a dynamic tunnel analysis program to simulate the construction process of center cross-diagram method and double sidewall drift method. Based on the stratum deformation, supporting force and analysis of plastic zone distribution, comparative analysis of engineering adaptability of different construction methods from the construction process and construction mechanics, get optimization tunnel construction scheme.