Abstract:

Improving the speech quality in low signal to noise ratio (SNR) environment is the key problem in speech recognition. There are many ways to solve this problem, and the empirical mode decomposition (EMD) is a widely applied method. But this method is usually easy to produce endpoint effects, so a further research on the extremum field mean mode decomposition (EMMD) method is made, by means of which the EMD changes the unitary use of extreme value point information and makes full use of the input signal information to calculate the mean value. Through calculating all the input information between extreme points, the endpoint effect is effectively restrained. Consequently a speech enhancement method based on EMMD is proposed. Experiment results show that the EMMD method can eliminate the DCcomponent implied in local data, restrains the endpoint effect in EMD and improves the SNR and speech quality.