Speech enhancement based on mEMD-VMD method

A novel and effective speech enhancement method is proposed for suppressing the white noise as well as non-stationary acoustic noises. The proposed method employs the combination of variational mode decomposition (VMD) and empirical mode decomposition (EMD) methods. In this method, first EMD is used to decompose the noisy speech signal into intrinsic mode functions (IMFs). Further, the VMD is applied on summation of selected IMFs. The main contribution of the proposed method is the selection of IMFs based on Hurst exponent and further applying steps of VMD method. The proposed modified EMD-VMD (mEMD-VMD) method is suitable to reduce the low-frequency noise as well as high-frequency noise. The proposed method gives the better results in terms of speech quality and composite measures. The proposed study is performed on eight speech signals under additive white Gaussian noise, street noise, babble noise, and airport noise taken from NOIZEUS database.