EMD based clear recursive thresholding (EMD-CRT) for speech enhancement

In this paper, a novel speech enhancement approach was proposed to improve the quality of the speech contaminated with various types of non-stationary noises. An EMD based clear recursive thresholding (EMD-CRT) approach was proposed in this approach, inspired by wavelet thresholding. This approach performs the thresholding operation on the noisy speech recursively, such that the non-stationary noises are getting filtered effectively. To evaluate the performance, the proposed approach was tested under various levels of SNR and also for various types of non-stationary noises like babble noise, car noise, restaurant noise and airport noise. A comparative analysis was also done with earlier approach to check the performance of the proposed approach. A subjective speech quality evaluation was also done by performing the mean opinion score (MOS).