Noise reduction apparatus and method
US6757395B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 2000 |
| Grant date | Jun 29, 2004 |
| Priority date | — |
| Expiry date | Jan 12, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L21/0208
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A multi-band spectral subtraction scheme is proposed, comprising a multi-band filter architecture, noise and signal power detection, and gain function for noise reduction. In one embodiment, the gain function for noise reduction consists of a gain scale function and a maximum attenuation function providing a predetermined amount of gain as a function of signal to noise ratio (“SNR”) and noise. In one embodiment, the gain scale function is a three-segment piecewise linear function, and the three piecewise linear sections of the gain scale function include a first section providing maximum expansion up to a first knee point for maximum noise reduction, a second section providing less expansion up to a second knee point for less noise reduction, and a third section providing minimum or no expansion for input signals with high SNR to minimize distortion. According to embodiments of the present invention, the maximum attenuation function can either be a constant or equal to the estimated noise envelope. The disclosed noise reduction techniques can be applied to a variety of speech communication systems, such as hearing aids, public address systems, teleconference systems, vo…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.