Constrained iterative speech enhancement with application to automatic speech recognition
John H. L. Hansen, Mark A. Clements · 2003
A set of iterative speech enhancement techniques using spectral constraints is extended and evaluated. The approaches apply inter- and intraframe spectral constraints to ensure optimum speech quality across all classes of speech. Constraints are applied on the basis of the presence of perceptually important speech characteristics found during the enhancement procedure. Results show improvement over past techniques for additive white noise distortions. Three points are addressed in the present study. First, a convenient and consistent terminating point for the iterative technique is presented which was previously unavailable. Second, the techniques have been generalized to allow for slowly varying, colored noise. Finally, a comparative evaluation has been performed to determine their usefulness as preprocessors for recognition in extremely noisy environments in the vicinity of 0 dB SNR.>