Previous work on bandpass modulation filtering for noise suppression has resulted in unwanted perceptual artifacts and decreased speech clarity. Artifacts are introduced mainly due to half-wave rectification, which is employed to correct for negative power spectral values resultant from the filtering process. In this paper, modulation frequency estimation (i.e., bandwidth extension) is used to improve perceptual quality. Experiments demonstrate that speech-component lowpass modulation content can be reliably estimated from bandpass modulation content of speech-plus-noise components. Subjective listening tests corroborate that improved quality is attained when the removed speech lowpass modulation content is compensated for by the estimate.
Bibliographic reference. Falk, Tiago H. / Stadler, Svante / Kleijn, W. Bastiaan / Chan, Wai-Yip (2007): "Noise suppression based on extending a speech-dominated modulation band", In INTERSPEECH-2007, 970-973.