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US 9,854,368 B2Granted
Method of operating a hearing aid system and a hearing aid system
AssigneeWidex A/S
InventorKristian Timm Andersen
Life of this patent
Estimating the term…
Abstract
A method of operating a hearing aid system using adaptive time-frequency analysis in order to provide improved noise reduction and enhanced speech intelligibility, and a hearing aid system (100, 200) comprising an adaptive filter bank.
Claims18
A method of operating a hearing aid system comprising the steps of:
- providing a digital input signal, representing the output from an input transducer of the hearing aid system,
- selecting a first window function,
- selecting a first length of the first window function,
- providing a second window function by zero padding the first window function such that the second window function has a second length, wherein the second length is larger than the first length,
- applying the second window function to the digital input signal and using a discrete Fourier transform to calculate a first time-frequency-distribution at a first point in time for the digital input signal,
- determining a first value of a measure of the energy in the digital input signal at a subsequent second point in time,
- applying the second window function to the digital input signal and using a discrete Fourier transform to calculate a second time-frequency-distribution at said second point in time,
- evaluating the first value of the measure of the energy in the digital input signal in order to select how to determine an adaptive time-frequency bin, having a specific frequency index, at said second point in time,
- using, in response to a first result of said evaluation, the second time-frequency distribution to determine the adaptive time-frequency bin,
- applying, in response to a second result of said evaluation, a phase shift, corresponding to the time shift between the first and the second point in time, to a frequency bin of the first time-frequency-distribution hereby providing a phase shifted time-frequency bin and adding the phase shifted time-frequency bin to the corresponding frequency bin of the second time-frequency-distribution, hereby providing the adaptive time-frequency bin,
- deriving a gain value for the hearing aid system based on the adaptive time-frequency bin in order to suppress noise,
- applying said gain value to a signal in a primary signal path of the hearing aid system, said primary signal path including at least the hearing aid system input transducer, and the hearing aid system output transducer.
9 more elements
A hearing aid system comprising an adaptive filter bank configured to provide an adaptive time-frequency distribution of a digital input signal representing the output from an input transducer of the hearing aid system, wherein said adaptive filter bank is configured such that a time-frequency bin X (k,i) of said time-frequency distribution is determined as either:
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- wherein X1 (k,i) is a time-frequency bin resulting from a discrete Fourier transform of a digital input signal based on a zero-padded second window comprising a single first window, and wherein k and i represent the frequency and time indices respectively,
- wherein X (k,i−1) represents a time-frequency bin based on the zero-padded second window comprising one or more of said first windows calculated at a previous time sample i−1 relative to the current time sample i,
- wherein L represents the length of the second window and R represents the hop-size of the first windows when summing these in the time domain,
- wherein X (k,i) is calculated as
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- in response to a determination of the digital input signal being stationary, and
- wherein X (k,i) is calculated as X1 (k, i) in response to a determination of the digital input signal not being stationary.
91 more elements
Dependencies are inferred from the claim text.