Noise suppressor for robust speech recognition
US8185389B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 2008 |
| Grant date | May 22, 2012 |
| Priority date | — |
| Expiry date | Jan 24, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L15/20
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Described is noise reduction technology generally for speech input in which a noise-suppression related gain value for the frame is determined based upon a noise level associated with that frame in addition to the signal to noise ratios (SNRs). In one implementation, a noise reduction mechanism is based upon minimum mean square error, Mel-frequency cepstra noise reduction technology. A high gain value (e.g., one) is set to accomplish little or no noise suppression when the noise level is below a threshold low level, and a low gain value set or computed to accomplish large noise suppression above a threshold high noise level. A noise-power dependent function, e.g., a log-linear interpolation, is used to compute the gain between the thresholds. Smoothing may be performed by modifying the gain value based upon a prior frame's gain value. Also described is learning parameters used in noise reduction via a step-adaptive discriminative learning algorithm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.