Granted Patent B2

US 12,277,949 · App. 18/342,025 · Granted Apr 15, 2025

Inventor: Knut Inge Hvidsten (Oslo, NO)

Assignee: PEXIP AS

G10L21/013H04L12/1831G10L2021/0135

Abstract

Claims (35)

1. A method for voice anonymization in an audio- or videoconferencing session, the method comprising:

receiving a plurality of input audio samples comprising speech;

calculating a frequency spectrum of each the plurality of input audio samples;

calculating a smoothed spectral magnitude envelope of a first of the plurality of frequency spectrums to determine a plurality of formant features of the speech, each of the plurality of formant features being located at different frequencies in the frequency spectrum;

determining one random scaling factor for the audio- or videoconferencing session;

determining, based on the one random scaling factor, a voice anonymization function shifting the formant location of at least one of the plurality of formants;

applying the voice anonymization function on the frequency spectrum of each the subsequent plurality of input audio samples in the audio- or videoconferencing session;

determining the one random scaling factor by using a random function to pick a number from two or more ranges of scaling factors;

wherein the voice anonymization function is a linear segment warping function performing linear scaling in the range 0-4 kHz;

the voice anonymization function is tapering off to zero warp at one half of a sampling frequency; and

determining a plurality of frequency gains for the voice anonymization function by calculating a ratio between the smoothed spectral magnitude envelope and a spectral magnitude envelope of the voice anonymization function applied on the smoothed spectral magnitude envelope.

2. A method for voice anonymization in an audio- or videoconferencing session, the method comprising:

receiving a plurality of input audio samples comprising speech;

calculating a frequency spectrum of each the plurality of input audio samples;

calculating a smoothed spectral magnitude envelope of a first of the plurality of frequency spectrums to determine a plurality of formant features of the speech, each of the plurality of formant features being located at different frequencies in the frequency spectrum;

determining one random scaling factor for the audio- or videoconferencing session;

determining, based on the one random scaling factor, a voice anonymization function shifting the formant location of at least one of the plurality of formants;

applying the voice anonymization function on the frequency spectrum of each the subsequent plurality of input audio samples in the audio- or videoconferencing session; and

determining a plurality of frequency gains for the voice anonymization function by calculating a ratio between the smoothed spectral magnitude envelope and a spectral magnitude envelope of the voice anonymization function applied on the smoothed spectral magnitude envelope.

3. The method of claim 2 , wherein the calculating of the frequency spectrum of each of the plurality of input samples is performed by a filterbank.

4. The method of claim 3 , wherein the filterbank is a Short-Time Fourier Transform filterbank.

5. An audio processing device for an audio- or videoconferencing session, the audio processing device:

receiving a plurality of input audio samples comprising speech:

calculating a frequency spectrum of each the plurality of input audio samples;

calculating a smoothed spectral magnitude envelope of a first of the plurality of frequency spectrums to determine a plurality of formant features of the speech, each of the plurality of formant features being located at different frequencies in the frequency spectrum;

determining one random scaling factor for the audio- or videoconferencing session;

determining, based on the one random scaling factor, a voice anonymization function shifting the formant location of at least one of the plurality of formants;

applying the voice anonymization function on the frequency spectrum of each the subsequent plurality of input audio samples in the audio- or videoconferencing session; and

determining a plurality of frequency gains for the voice anonymization function by calculating a ratio between the smoothed spectral magnitude envelope and a spectral magnitude envelope of the voice anonymization function applied on the smoothed spectral magnitude envelope.

6. The audio processing device of claim 5 , adapted to determining the one random scaling factor by using a random function to pick a number from two or more ranges of scaling factors.

7. The audio processing device of claim 5 , wherein the voice anonymization function is a linear segment warping function performing linear scaling in the range 0-4 kHz.

8. The audio processing device of claim 7 , wherein the voice anonymization function is tapering off to zero warp at one half of a sampling frequency.

9. The audio processing device of claim 5 , comprising a filterbank calculating the frequency spectrum of each of the plurality of input samples.

10. The audio processing device of claim 9 , wherein the filterbank is a Short-Time Fourier Transform filterbank.

11. The audio processing device of claim 10 , wherein the audio processing device is integrated in at least one of a multipoint conferencing node, MCN, and a videoconferencing terminal.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (13)