Electronic appliance and voice signal processing method for use in the same
View Patent ↗An electronic appliance includes a speaker which outputs a first sound wave based on a first voice signal generated from the electronic appliance, and a microphone to detect a second sound wave on which a sound wave generated for control of the electronic appliance is superimposed to output a second voice signal. A first waveform generator generates a first waveform signal based on the first voice signal, and a second waveform generator generates a second waveform signal based on the second voice signal. A waveform shaping unit outputs a third waveform signal in which the first waveform signal is enlarged in a time axis direction, and a subtracter subtracts the third waveform signal from the second waveform signal.
1. An electronic appliance comprising:
a speaker which subjects a first voice signal generated from the electronic appliance to electricity-sound conversion to output a converted first sound wave;
a sound detector which detects a second sound wave where a specific sound wave generated for control of the electronic appliance is superimposed on a third sound wave based on the first sound wave emitted from the speaker and which subjects the second sound wave to sound-electricity conversion to output a second voice signal, wherein the third sound wave is originally the same signal as the first sound wave but having different component and amplitude owing to a transmission characteristic along a path from the speaker to the sound detector;
a first waveform generator which subjects the first voice signal to predetermined signal processing to generate a first waveform signal;
a second waveform generator which subjects the second voice signal output from the sound detector to predetermined signal processing to generate a second waveform signal;
a waveform shaping unit which enlarges the first waveform signal in a time axis direction to output a third waveform signal;
a subtracter which subtracts the third waveform from the second waveform signal to output a fourth waveform signal of the specific sound wave;
wherein the first waveform generator includes a first offset component removal section to generate a voice signal, and a first absolute value forming circuit which forms an absolute value of the voice signal output from the first offset component removal section to output the first waveform signal, and
the second waveform generator includes a second offset component removal section to generate a voice signal in which an offset component is removed from the second voice signal, and a second absolute value forming circuit which forms an absolute value of the voice signal output from the second offset component removal section to output the second waveform signal.
2. The electronic appliance according to claim 1 , wherein the waveform shaping unit includes a plurality of retaining units which retain the first waveform signals for a predetermined time, and an extractor which extracts maximum values of the plurality of first waveform signals output from the plurality of retaining units and which synthesizes the plurality of extracted maximum values in time series to generate the third waveform signal.
3. A voice signal processing method comprising:
an electricity-sound conversion step of subjecting a first voice signal generated from an electronic appliance to electricity-sound conversion to output a first sound wave by a speaker;
a sound detecting step of detecting a second sound wave in which a specific sound wave generated for control of the electronic appliance is superimposed on a third sound wave based on the first sound wave emitted from the speaker by a sound detector, wherein the third sound wave is originally the same signal as the first sound wave but having different component and amplitude owing to a transmission characteristic along a path from the speaker to the sound detector;
a sound-electricity conversion step of subjecting the second sound wave to sound-electricity conversion to output a second voice signal;
a first waveform generation step of subjecting the first voice signal to predetermined signal processing to generate a first waveform signal;
a second waveform generation step of subjecting the second voice signal to predetermined signal processing to generate a second waveform signal;
a waveform shaping step of enlarging the first waveform signal in a time axis direction to output a third waveform signal;
a subtraction step of Subtracting the third waveform signal from the second waveform signal to output a fourth waveform signal of the specific sound wave;
wherein the first waveform generation step includes a first offset component removal step of generating a voice signal in which an offset component is removed from the first voice signal, and a first absolute value forming step of forming an absolute value of the voice signal output in the first offset component removal step to output the first waveform signal, and
the second waveform generation step includes a second offset component removal step of generating a voice signal in which an offset component is removed from the second voice signal, and a second absolute value forming step of forming an absolute value of the voice signal output in the second offset component removal step to output the second waveform signal.
4. The voice signal processing method according to claim 3 , further comprising:
a retaining step of retaining the plurality of first waveform signals for a predetermined time, respectively; and
an extraction step of extracting maximum values of the plurality of first waveform signals and synthesizing the plurality of extracted maximum values in time series to generate the third waveform signal.