Apparatus and method for detecting acoustic feedback

An acoustic-feedback detection method comprising steps

• detecting a first signal level of sound signals obtained from a position in a sound-signal system in which a microphone and speaker are connected;
• extracting, from the sound signals of which the first signal level is detected, signals in a band having a bandwidth predetermined for each of at least one predetermined center frequency;
• detecting a second signal level of the signals in each band, the signals being extracted from the sound signals;
• determining whether or not acoustic feedback is occurring based on a threshold determined according to the detected signal level of the sound signals and a waveform of the detected second signal level of the signals in each band;
• detecting a third signal level of external sound signals to be supplied to a position in the sound-signal system;
• extracting, from the external sound signals, signals in a band having a bandwidth predetermined for each of the at least one center frequency;
• and
• detecting a fourth signal level of the signals in each band, the signals being extracted from the external sound signals;
• wherein in the determining step, whether or not acoustic feedback is occurring is determined based on a first result of the detection of the third signal level of the external sound signals and a second result of the detection of the fourth signal level of the signals in each band.

An acoustic-feedback detection apparatus comprising:

• at least one processor;
• a first level detecting section configured to detect a first signal level of sound signals obtained from a position in a sound-signal system in which a microphone and speaker are connected;
• a first extracting section configured to extract, from the sound signals of which the first signal level is detected, signals in a band having a bandwidth predetermined for each of at least one predetermined center frequency;
• a second level detecting section configured to detect a second signal level of the signals in each band, the signals being extracted by the first extracting section;
• a determining section configured to determine whether or not acoustic feedback is occurring based on a threshold determined according to the first signal level detected by the first level detecting section and a waveform of each second signal level detected by the second level detecting section;
• a third level detecting section configured to detect a third signal level of external sound signals to be supplied to a position in the sound-signal system;
• a second extracting section configured to extract, from the external sound signals, signals in the band having the bandwidth predetermined for each of the at least one center frequency;
• and
• a fourth level detecting section configured to detect a fourth signal level of the signals in each band, the signals being extracted by the second extracting section;
• wherein the determining section determines whether or not acoustic feedback is occurring based on a first output resulting from the detection performed by the third level detecting section and a second output resulting from the detection performed by the fourth level detecting section.