Audio processing apparatus, audio processing method, and recording medium

An audio processing method implemented by a computer, the method comprising:

• receiving an audio signal from a microphone serving to collect sound in a space;
• determining whether a level of a reference signal is equal to or greater than a threshold, the reference signal being a reproduction signal reproduced by a speaker serving to output audio sound to the space;
• outputting, as an output signal to a speech recognition device, a removal signal obtained by removing an audio component of the reference signal from the audio signal;
• outputting, as an output signal to the speech recognition device, a replacement signal in place of the removal signal in response to determining that the level of the reference signal is equal to or greater than the threshold, the replacement signal being at least one of comfort noise and a mute signal;
• and
• outputting, to a display, information representing that speech recognition is being stopped, the information being output in response to determining that the level of the reference signal is equal to or greater than the threshold.

A non-transitory computer-readable recording medium on which programmed instructions are recorded, the programmed instructions causing a computer to execute processing, the processing comprising:

• receiving an audio signal from a microphone serving to collect sound in a space,
• determining whether a level of a reference signal is equal to or greater than a threshold, the reference signal being a reproduction signal reproduced by a speaker serving to output audio sound to the space,
• outputting, as an output signal to a speech recognition device, a removal signal obtained by removing an audio component of the reference signal from the audio signal, and
• outputting, as an output signal to the speech recognition device, a replacement signal in place of the removal signal in response to determining that the level of the reference signal is equal to or greater than the threshold, the replacement signal being at least one of comfort noise and a mute signal,
• wherein the threshold is a value that matches a level of the reproduction signal at which distortion starts to occur in an audio sound output from the speaker in response to the level of the reproduction signal being gradually increased.