Non-Air Conducted Speech Enhancement Based on Iterative Spectral Subtraction Method

A novel non-air conducted speech detecting method has been developed in our laboratory by using millimeter wave radar technology. Because of the special attributes of the millimeter wave, this method may considerably extend the capabilities of traditional speech detecting methods. However, radar speech is substantially degraded by additive combined noises that include radar harmonic noise, electrocircuit noise, and ambient noise. This study, therefore, proposed an iterative spectral subtraction method which can be adaptive estimate noise spectrum at every iteration time, and reduce the musical noise remained in the previous spectral subtraction process. Results from simulations as well as evaluations confirm that enhanced non-air conducted speech is more pleasant to listeners than speech produced by traditional spectral subtraction algorithms. This suggests that the proposed method satisfactorily reduces whole-frequency and musical noises and produces good speech quality.