Noise reduction system
US7224810B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 12, 2003 |
| Grant date | May 29, 2007 |
| Priority date | — |
| Expiry date | Dec 7, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG10L21/0208
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The disclosure includes description of a method of noise reduction according to one possible implementation. An audio signal is sampled at a sample rate f. The audio signal is converted to a digital signal in the time domain. For each of a series of frames of time, the digital signal in the time domain is converted to a digital signal in frequency domain for the frame of time. The converting includes determining a set of frequency domain values. The frequency domain values in the set are created by a set of digital filters, and the digital filters are related to each other by a constant ratio of filter bandwidth to center frequency, related to a perceptual scale for audio processing. A set of minimum magnitude frequency domain values is obtained. These values include, at each frequency represented by the frequency domain values, a frequency domain value having a minimum magnitude from among frequency domain values for such frequency over a time interval spanning multiple frames of time. The set of minimum magnitude frequency domain values are subtracted from the audio signal and the frequency domain, for a particular frame of time. The subtracted audio signal is converted to the ti…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.