Research and implementation of speech enhancement based on db4 wavelet transform

In the actual transmission process, the signal will be disturbed by a lot of noise, which directly affects the quality of the signal. The purpose of speech enhancement technology is to denoise the signal containing noise, which is a method to improve the effectiveness of signal and remove noise. This paper is based on the wavelet transform threshold denoising method, in the wavelet transform wavelet denoising processing, research a new threshold selection algorithm, to achieve a better noise reduction effect, so as to achieve speech enhancement. Write a speech signal processing program in Matlab software, add other recorded speech signals to the program, process the signal with Gaussian noise, then replace the proposed algorithm into the speech signal processing program to denoise, and observe the signal waveform diagram reconstructed at last. It is compared with the time domain waveform of speech signal, soft threshold and hard threshold, and determines whether the new algorithm can achieve speech enhancement according to whether the signal denoising effect is improved.