Noise suppression in speech signals
AssigneeVereniging voor Christelijk Hoger Onderwijs, Wetenschappelijk Onderzoek en Patiëntenzor
InventorsFinn Dubbelboer, Tammo Houtgast
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Abstract
During speech processing a filter adjusts a spectral envelope of an input speech signal with a frequency dependent adjustment factor. The adjustment factors for respective spectral components are selected dependent on the input speech signal. The factor is set to a first or second non-zero value, the second value being smaller than the first value, when a strength average for the spectral component is above and below a threshold value respectively.
Claims8
A speech processing apparatus comprising:
- a filter, of a processor, configured to adjust a spectral envelope of an input speech signal with a frequency dependent adjustment factor;
- a factor selector for selecting the adjustment factor for respective spectral components each dependent on the input speech signal, the factor selector being configured to select the factor between a first or second non-zero value, the second value being smaller than the first value, when a strength average for the spectral component is above and below a threshold value respectively, whereby a relative strength of different spectral components below the threshold value is preserved;
- wherein the filter is configured to compute sets of spectral components for a series of time frames and to compute adjusted spectral components, wherein the spectral components have been adjusted by the adjustment factors;
- wherein the factor selector comprising an averager configured to compute the strength average for the spectral component for each time frame by averaging over a plurality of the time frames adjacent the time frame for which the strength average is computed.
A method of processing a speech signal, the method comprising:
- adjusting a spectral envelope of the speech signal with a frequency dependent adjustment factor;
- selecting the adjustment factor for respective spectral components each dependent on the input speech signal, the factor being selected between a first or a second non-zero value, the second value being smaller than the first value, when a strength average for the spectral component is above and below a threshold value respectively, whereby a relative strength of different of different spectral components below the threshold value is preserved;
- computing sets of spectral components for a series of time frames and to compute adjusted spectral components wherein the spectral components have been adjusted by the adjustment factors;
- computing the strength average for the spectral component for each time frame by averaging over a plurality of the time frames adjacent the time frame for which the strength average is computed.
Dependencies are inferred from the claim text.