Communication support system

Patent metadata

Field	Value
Publication number	US-12112733-B2
Application number	US-202318113225-A
Country	US
Kind code	B2
Filing date	Feb 23, 2023
Priority date	Feb 25, 2022
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

A noise canceling adaptive filter outputs, from a front seat speaker, a noise canceling sound generated by applying a transfer function X(z) adapted by an adaptive operation using an output of a front seat microphone as an error to an output sound of a sound source apparatus. An output of the front seat microphone is added to an output of an audio feedback canceling filter by a second adder, added to an output sound of the sound source apparatus by a third adder, and output from a rear seat speaker. The audio feedback canceling filter applies a transfer function X′(z) and a transfer function C{circumflex over ( )}(z) on an output of the second adder and outputs a resultant. The transfer function C{circumflex over ( )}(z) corresponds to a transfer function C(z) from the front seat speaker to the front seat microphone. In synchronization control, the transfer function X(z) is set as the transfer function X′(z).

First claim

The invention claimed is:

1. A communication support system for supporting communication by speech between a user in a first area and a user in a second area, the communication support system comprising:
a sound source apparatus;
a first area speaker that is installed in the first area and that is configured to receive a sound source output sound signal corresponding to sound output from the sound source apparatus;
a second area speaker installed in the second area;
a second area microphone installed in the second area; and
a signal processing apparatus, comprising:
a noise canceling adaptive filter configured to generate a noise canceling sound signal that is applied to the second area speaker,
an audio feedback canceling section configured to generate a second area speech sound signal that is added to the sound source output sound signal and that is applied to the first area speaker, and
a transfer function update processing section,

wherein the noise canceling adaptive filter is configured to generate the noise canceling sound signal by applying a transfer function X(z) adapted by an adaptive operation using a second area sound signal picked up by the second area microphone, as an error, to the sound source output sound signal to generate the noise canceling sound signal,
wherein the audio feedback canceling section includes a first filter, a second filter that is configured to use an output of the first filter as an input, and an adder that that is configured to add the second area sound signal to an output of the second filter and to output a result of the addition as the second area speech sound signal,
wherein the first filter is configured to receive an output of the adder as an input,
wherein the second filter has a transfer function equivalent to a transfer function C(z) from the second area speaker to the second area microphone, and
wherein the transfer function update processing section is configured to update a transfer function of the first filter to a transfer function that is the same as the transfer function X(z) adapted by the adaptive operation performed by the noise canceling adaptive filter.

2. The communication support system according to claim 1 , further comprising:
a first area microphone installed in the first area,
wherein a first area sound signal picked up by the first area microphone is applied to the second area speaker after being added to the noise canceling sound signal.

3. The communication support system according to claim 1 , wherein:
the noise canceling adaptive filter is configured to adapt the transfer function X(z) by an adaptive operation in accordance with a Filtered-X LMS algorithm using a signal obtained by applying a transfer function equivalent to the transfer function C(z) to the sound source output sound signal as a reference signal and the second area sound signal as an error.

4. The communication support system according to claim 3 , wherein:
a seat in the first area and a seat in the second area in a vehicle are different from each other.

5. A communication support system for supporting communication by speech between a user in a first area and a user in a second area, the communication support system comprising:
a sound source apparatus;
a first area speaker that is installed in the first area and that is configured to receive a sound source output sound signal corresponding to sound output from the sound source apparatus;
a first area microphone installed in the first area;
a second area speaker that is installed in the second area and that is configured to receive a first area sound signal picked up by the first area microphone;
a second area microphone installed in the second area; and
a signal processing apparatus, comprising:
a noise canceling adaptive filter configured to generate a noise canceling sound signal that is applied to the second area speaker after being added to the first area sound signal,
an echo canceling section,
an audio feedback canceling section configured to generate a second area speech sound signal that is added to the sound source output sound signal that is applied to the first area speaker,
a reference signal generation filter configured to receive the sound source output sound signal as an input, and
a transfer function update processing section,

wherein the echo canceling section includes an echo canceling adaptive filter configured to receive the first area sound signal as an input and an echo canceling adder configured to add an output of a second area sound signal picked up by the second area microphone to an echo canceling sound signal that is an output of the echo canceling adaptive filter and to output a result of the addition,
wherein the echo canceling adaptive filter is configured to generate the echo canceling sound signal by applying a transfer function Q(z) adapted by an adaptive operation using an output of the echo canceling adder as an error to the first area sound signal,
wherein the reference signal generation filter is configured to share the transfer function Q(z) of the echo canceling adaptive filter as the transfer function of the reference signal generation filter,
wherein the noise canceling adaptive filter is configured to generate the noise canceling sound signal by applying, to the sound source output sound signal, a transfer function X(z) adapted by an adaptive operation in accordance with the Filtered-X LMS algorithm using an output of the echo canceling adder as an error and an output of the reference signal generation filter as a reference signal,
wherein the audio feedback canceling section includes a first filter, a second filter configured to use an output of the first filter as an input, and an audio feedback canceling adder configured to add an output of the echo canceling adder to an output of the second filter and to output a result of the addition as the second area speech sound signal,
wherein the first filter is configured to receive an output of the audio feedback canceling adder as an input, and
wherein the transfer function update processing section is configured to update a transfer function of the first filter to a transfer function the same as the transfer function X(z) adapted by the adaptive operation performed by the noise canceling adaptive filter and to update a transfer function of the second filter to a transfer function that is the same as the transfer function Q(z) adapted by the adaptive operation performed by the echo canceling adaptive filter.

6. The communication support system according to claim 5 , wherein:
the echo canceling adaptive filter is configured to adapt the transfer function Q(z) by an adaptive operation in accordance with the LMS algorithm using the first area sound signal as a reference signal and an output of the echo canceling adder as an error.

7. The communication support system according to claim 6 , wherein:
a seat in the first area and a seat in the second area in a vehicle are different from each other.

Assignees

• Alps Alpine Co Ltd

Inventors

• Tachi Ryosuke

Classifications

• G10K2210/505

  Echo cancellation, e.g. multipath-, ghost- or reverberation-cancellation · CPC title

• G10K2210/3055

  Transfer function of the acoustic system · CPC title

• G10K2210/3046

  Multiple acoustic inputs, multiple acoustic outputs · CPC title

• G10K2210/3044

  Phase shift, e.g. complex envelope processing · CPC title

• G10K2210/3028

  Filtering, e.g. Kalman filters or special analogue or digital filters · CPC title