Formant dependent speech signal enhancement
AssigneeNuance Communications, Inc.
InventorsMohamed Krini, Ingo Schalk-Schupp, Markus Buck
Life of this patent
Estimating the term…
Abstract
An arrangement is described for speech signal processing. An input microphone signal is received that includes a speech signal component and a noise component. The microphone signal is transformed into a frequency domain set of short-term spectra signals. Then speech formant components within the spectra signals are estimated based on detecting regions of high energy density in the spectra signals. One or more dynamically adjusted gain factors are applied to the spectra signals to enhance the speech formant components.
Claims21
A computer-implemented method employing at least one hardware implemented computer processor for speech signal processing comprising:
- receiving an input microphone signal having a speech signal component and a noise component;
- transforming the microphone signal into a frequency domain set of short term spectra signals;
- estimating speech formant components within the spectra signals based on detecting regions of high energy density in the spectra signals;
- applying one or more dynamically adjusted gain factors to the spectra signals to enhance the speech formant components only during voiced speech phonemes and on the speech formant components having signal-to-noise ratio above a threshold;
- adjusting the gain factors around a center frequency of the speech formant components based upon a presumed reliability of the estimation of the speech formant components, including adjusting the gain factors to boost the speech formant components more for higher reliability formant estimations than lower reliability formant estimations;
- and
- requiring a minimum clearance between ones of the speech formant components.
A speech signal processing system comprising:
- a speech signal input for receiving a microphone signal having a speech signal component and a noise component;
- a signal pre-processor for transforming the microphone signal into a frequency domain set of short term spectra signals;
- a formant estimating module for estimating speech formant components within the spectra signals based on detecting regions of high energy density in the spectra signals;
- and
- a formant enhancement module for applying one or more dynamically adjusted gain factors to the spectra signals to enhance the speech formant components only during voiced speech phonemes and on the speech formant components having signal-to-noise ratio above a threshold and for adjusting the gain factors around a center frequency of the speech formant components based upon a presumed reliability of the estimation of the speech formant components, wherein the gain factors are adjusted to boost the speech formant components more for higher reliability formant estimations than lower reliability formant estimations, and wherein there is a minimum clearance between ones of the speech formant components.
Dependencies are inferred from the claim text.