Abstract: A method of reducing noise in an audio signal, comprising the steps of: using a furrow filter to select spectral components that are narrow in frequency but relatively broad in time; using a bar filter to select spectral components that are broad in frequency but relatively narrow in time; analyzing the relative energy distribution between the output of the furrow and bar filters to determine the optimal proportion of spectral components for the output signal; and reconstructing the audio signal to generate the output signal. A second pair of time-frequency filters may be used to further improve intelligibility of the output signal. The temporal relationship between the furrow filter output and the bar filter output may be monitored so that the fricative components are allowed primarily at boundaries between intervals with no voiced signal present and intervals with voice components. A noise reduction system for an audio signal.

Abstract: Configurations disclosed herein include systems, methods, and apparatus that may be applied in a voice communications and/or storage application to remove, enhance, and/or replace the existing context.

Abstract: For enabling an improved reconstruction of a high frequency band of an audio signal in a split-band coding approach, a value representative of a background noise level in an audio signal that is to be encoded is determined. Further, a gain value for the higher frequency band is determined. Further, a correction factor for the determined gain value is determined based on the determined value representative of the background noise level. The correction factor may be used at an encoding end for correcting the gain value before a corresponding codebook index is provided to a decoding end. Alternatively, the correction factor may be provided together with a codebook index for the gain value to a decoding end, and the decoding end may use the correction factor to correct the gain value if appropriate.