Echo cancellation device, non-transitory computer readable medium storing echo cancellation program, and echo cancellation

A non-transitory computer readable medium storing an echo cancellation program that suppresses an echo signal component corresponding to an output voice signal in an echo cancellation device,

• the echo cancellation device comprising:
• a voice output unit configured to output, to a space, the output voice signal in which frequency components equal to or higher than a predetermined target frequency are suppressed, as a first voice signal;
• a voice input unit configured to pick up a second voice signal propagating through the space and generate an acoustic signal including a frequency component higher than the predetermined target frequency;
• and
• an operation unit configured to execute a program,
• the echo cancellation program comprising:
• delay processing for delaying the output voice signal;
• voice section detection processing for detecting that the output voice signal delayed by the delay processing corresponds to a voice section including a voice signal component, and generating voice section information;
• echo signal reduction processing for updating a filter coefficient for setting a degree of suppression of the echo signal component from the acoustic signal, and generating, from the acoustic signal, a transmitting signal in which the echo signal component is reduced;
• and
• filter coefficient update determination processing for determining whether or not the acoustic signal includes an echo signal component corresponding to the output voice signal when the voice section information indicates the voice section, and updating the filter coefficient when the filter coefficient update determination processing determines that the acoustic signal includes the echo signal component,
• wherein in the filter coefficient update determination processing, a feature value of the acoustic signal is calculated and an instruction to update the filter coefficient is sent when a difference between a first feature value of a frequency band equal to or lower than the predetermined target frequency and a second feature value of the frequency band higher than the predetermined target frequency is equal to or greater than a preset update determination threshold.

An echo cancellation method that suppresses an echo signal component corresponding to an output voice signal in an echo cancellation device,

• the echo cancellation device comprising:
• a voice output unit configured to output, to a space, an output voice signal in which frequency components equal to or higher than a predetermined target frequency are suppressed, as a first voice signal;
• and
• a voice input unit configured to pick up a second voice signal propagating through the space and generate an acoustic signal including a frequency component higher than the predetermined target frequency,
• the echo cancellation method comprising:
• delaying the output voice signal;
• detecting that the delayed output voice signal corresponds to a voice section including a voice signal component and generating voice section information;
• updating a filter coefficient for setting a degree of suppression of the echo signal component from the acoustic signal, and generating, from the acoustic signal, a transmitting signal in which the echo signal component is reduced;
• calculating a feature value of the acoustic signal and calculating, as an echo signal determination value, a difference between a first feature value of a frequency band equal to or lower than the predetermined target frequency and a second feature value of the frequency band higher than the predetermined target frequency;
• and
• determining that the acoustic signal includes an echo signal component corresponding to the output voice signal when the voice section information indicates the voice section and the echo signal determination value is equal to or greater than a preset update determination threshold, and sending an instruction to update the filter coefficient.