US 12,537,021 B2 · Low complexity sub-band speech onset detection (SOD)

Abstract

Techniques are disclosed for a low-power and low-complexity speech onset detector (SOD) that uses a fractional-band filter structure and spectral subtraction technique to derive sub-band energy profiles to detect the onset of speech in the presence of noise. The SOD derives the sub-band energy profiles by filtering and down-sampling a full-band input audio signal using the fractional-bandwidth filter structure, which may be a low-pass filter with a cut-off frequency that is a fraction of the full bandwidth of the input signal. The SOD flexibly estimates the average noise energy across frames and the current frame speech energy in each sub-band to track noise and speech energy levels across the frames for each of the sub-bands to determine one or more band thresholds used to detect active speech. The sub-band energy profiles leverage any separation in frequency between noise and speech to detect the onset of speech in a target signal.

Claims20

Dependent claims

A method of detecting speech by a device, the method comprising:

receiving an audio signal from one or more microphones;
filtering the audio signal to generate sampled audio data corresponding to a plurality of sampling rates for a plurality of frames of the audio signal;
estimating noise energy and noise-removed energy for a plurality of sub-bands for each of the frames based on the sampled audio data corresponding to the plurality of sampling rates;
tracking noise energy levels and speech energy levels across the plurality of frames based on the estimated noise energy and the estimated noise-removed energy for each of the sub-bands to determine one or more band thresholds for each of the sub-bands based on a maximum of the estimated noise-removed energy;
and
determining a presence of speech or noise in each of the frames based on the one or more band thresholds for each of the sub-bands.

3 more elements

An apparatus comprising:

one or more microphones configured to capture sound to produce an audio signal;
and
a processing system configured to:
filter the audio signal to generate sampled audio data corresponding to a plurality of sampling rates for a plurality of frames of the audio signal;
estimate noise energy and noise-removed energy for a plurality of sub-bands for each of the frames based on the sampled audio data corresponding to the plurality of sampling rates;
track noise energy levels and speech energy levels across the plurality of frames based on the estimated noise energy and the estimated noise-removed energy for each of the sub-bands to determine one or more band thresholds for each of the sub-bands based on a maximum of the estimated noise-removed energy;
and
determine a presence of speech or noise in each of the frames based on the one or more band thresholds for each of the sub-bands.

5 more elements

Dependencies are inferred from the claim text.

Low complexity sub-band speech onset detection (SOD)

Life of this patent

Low complexity sub-band speech onset detection (SOD)

Life of this patent

Abstract

Claims20