Communication support system

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.