Abstract: Aiming at the problem that noise, echo and other factors interfered with the quality and intelligibility of the signal in the process of speech signal transmission, we proposed a speech signal enhancement method based on optimized variational mode decomposition algorithm and improved wavelet threshold. Firstly, the modal decomposition parameters were optimized by using sparrow search algorithm, and the modal components were obtained by resolving the speech signal. Secondly, according to the correlation coefficient and center frequency between the modal component and the original signal, the high-frequency noise component was eliminated, and the modal component close to the original signal was retained as pure speech, while the other modal components were regarded as noisy speech, and the wavelet threshold processing was carried out. Finally, the pure speech and the processed noise modal components were reconstructed to obtain the enhanced speech signals. The results show that the method has better speech enhancement effect than a single method, the optimized variational mode decomposition algorithm and the improved threshold and threshold function achieve better enhancement effect than the traditional methods, which is suitable for all kinds of noise environment, and effectively improve the quality and intelligibility of speech signals.

Key words: speech enhancement, sparrow search algorithm, variational mode decomposition, wavelet threshold, correlation coefficient