公开(公告)号：US10482896B2

公开(公告)日：2019-11-19

申请号：US15991811

申请日：2018-05-29

Applicant: Retune DSP ApS

Inventor： Ulrik Kjems ,  Thomas Krogh Andersen

IPC: G10L21/0232 ,  G10L21/0316 ,  G10L21/038

Abstract: The present invention relates to a multi-band noise reduction system for digital audio signals producing a noise reduced digital audio output signal from a digital audio signal. The digital audio signal comprises a target signal and a noise signal, i.e. a noisy digital audio signal. The multi-band noise reduction system operates on a plurality of sub-band signals derived from the digital audio signal and comprises a second or adaptive signal-to-noise ratio estimator which is configured for filtering a plurality of first signal-to-noise ratio estimates of the plurality of sub-band signals with respective time-varying low-pass filters to produce respective second signal-to-noise ratio estimates of the plurality of sub-band signals. A low-pass cut-off frequency of each of the time-varying low-pass filters is adaptable in accordance with a first signal-to-noise ratio estimate determined by a first signal-to-noise ratio estimator and/or the second signal-to-noise ratio estimate of the sub-band signal.

公开(公告)号：US10412488B2

公开(公告)日：2019-09-10

申请号：US15753139

申请日：2016-07-18

Applicant: Retune DSP ApS

Inventor： Ulrik Kjems ,  Thomas Krogh Andersen

IPC: G10L15/20 ,  H04R3/00 ,  G10L21/0216 ,  G10L25/84 ,  G10L21/0232 ,  G10L15/08

Abstract: The present invention relates in one aspect to a microphone array signal processing system comprising a digital buffer coupled to a signal input and configured to store first and second digital audio signals. A beamformer analyzer is configured to, in response to a first voice trigger, determine noise statistics based on the first signal segment of the first digital audio signal and a first signal segment of the second digital audio signal. A coefficients calculator is configured to calculate a first set of fixed beamformer coefficients of a beamforming algorithm. The beamforming algorithm is configured for applying the first set of fixed beamformer coefficients to the first signal segments of the first and second digital audio signals retrieved from the digital buffer to produce a noise reduced digital audio signal.

公开(公告)号：US10109290B2

公开(公告)日：2018-10-23

申请号：US15318046

申请日：2015-06-10

Applicant: Retune DSP ApS

Inventor： Ulrik Kjems ,  Thomas Krogh Andersen

IPC: G10L21/0232 ,  G10L21/0316 ,  G10L21/038

Abstract: The present invention relates to a multi-band noise reduction system for digital audio signals producing a noise reduced digital audio output signal from a digital audio signal. The digital audio signal comprises a target signal and a noise signal, i.e. a noisy digital audio signal. The multi-band noise reduction system operates on a plurality of sub-band signals derived from the digital audio signal and comprises a second or adaptive signal-to-noise ratio estimator which is configured for filtering a plurality of first signal-to-noise ratio estimates of the plurality of sub-band signals with respective time-varying low-pass filters to produce respective second signal-to-noise ratio estimates of the plurality of sub-band signals. A low-pass cut-off frequency of each of the time-varying low-pass filters is adaptable in accordance with a first signal-to-noise ratio estimate determined by a first signal-to-noise ratio estimator and/or the second signal-to-noise ratio estimate of the sub-band signal.

公开(公告)号：US20180277139A1

公开(公告)日：2018-09-27

申请号：US15991811

申请日：2018-05-29

Applicant: Retune DSP ApS

Inventor： Ulrik Kjems ,  Thomas Krogh Andersen

IPC: G10L21/0232 ,  G10L21/0316 ,  G10L21/038

CPC classification number: G10L21/0232 ,  G10L21/0316 ,  G10L21/038

Abstract: The present invention relates to a multi-band noise reduction system for digital audio signals producing a noise reduced digital audio output signal from a digital audio signal. The digital audio signal comprises a target signal and a noise signal, i.e. a noisy digital audio signal. The multi-band noise reduction system operates on a plurality of sub-band signals derived from the digital audio signal and comprises a second or adaptive signal-to-noise ratio estimator which is configured for filtering a plurality of first signal-to-noise ratio estimates of the plurality of sub-band signals with respective time-varying low-pass filters to produce respective second signal-to-noise ratio estimates of the plurality of sub-band signals. A low-pass cut-off frequency of each of the time-varying low-pass filters is adaptable in accordance with a first signal-to-noise ratio estimate determined by a first signal-to-noise ratio estimator and/or the second signal-to-noise ratio estimate of the sub-band signal.