WO2005008910A1 - 通話装置 - Google Patents
通話装置 Download PDFInfo
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- WO2005008910A1 WO2005008910A1 PCT/JP2004/009697 JP2004009697W WO2005008910A1 WO 2005008910 A1 WO2005008910 A1 WO 2005008910A1 JP 2004009697 W JP2004009697 W JP 2004009697W WO 2005008910 A1 WO2005008910 A1 WO 2005008910A1
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- end signal
- audio
- echo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M9/00—Arrangements for interconnection not involving centralised switching
- H04M9/08—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
- H04M9/082—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic using echo cancellers
Definitions
- the present invention relates to a communication device, and more particularly to a communication device capable of reliably suppressing echo even when the relative position between a microphone and a speaker changes.
- a conventional communication device has a single microphone, a speaker and a microphone
- the conventional communication device disclosed in Japanese Patent Application Laid-Open No. 2000-244600 is located on the near end side of a voice switch 51 that performs simultaneous call processing.
- a first echo canceller 52 is provided, and a second echo canceller 53 is provided on the opposite side of the first echo canceler 52 with the voice switch 51 interposed therebetween.
- the first echo canceler 52 generates a pseudo echo based on the transfer function of the sound propagation path from the speech power 54 set to the first echo canceller 52 to the microphone 55, and a subtracter 58 By subtracting the pseudo echo from the near-end signal output from the microphone 55, the echo output due to the sound output from the speaker 54 being collected by the microphone 55 is suppressed. .
- the second echo canceller 53 is for suppressing the echo generated when the sound collected by the microphone goes around to the speed side when performing “2-4 wire conversion”. In the “4-wire communication device”, the second echo canceller 53 and the voice switch 51 are unnecessary.
- the coefficients of the transfer function set in the first echo canceller 52 and the second echo canceller 53 are sequentially updated according to the temporal change of the propagation path.
- a first microphone having a different distance from a speaker.
- a well-known type that includes a microphone and a second microphone, and effectively suppresses echo contained in the output of the other microphone based on the output of one microphone and microphone.
- the output of the speaker 54 is detected by the first microphone 55 and the second microphone 56. It has become.
- the echo suppression characteristics of the echo canceller 57 installed after the first microphone 55 indicate the sound propagation from the speaker 54 to the first microphone 55 and the second microphone 56. Based on the transfer function of the path, the difference between the output of the first microphone 55 and the output of the second microphone 56, which is the output of the subtractor 58, is set to be minimized.
- JP-A-2000-244670 and JP-A-8-223275 disclose that the echo suppression characteristic of the echo canceller is determined based on the sound propagation path from the speaker to the microphone. Have been.
- the echo canceller disclosed in JP-A-2000-244670 and JP-A-8-223275 described above is applied to a communication device capable of changing the It can be seen that it is necessary to change according to the relative position between the force and the microphone.
- JP-A-2000-244670 and JP-A-8-223275 do not disclose or suggest changing the echo suppression characteristic according to the relative position between the speaker and the microphone.
- the echo cancellers disclosed in JP-A-2000-244670 and JP-A-8-223275 are applied to a communication device capable of changing a relative position between a speaker and a microphone, the speaker and the microphone become incompatible.
- the relative position of is changed, the echo suppression characteristics of the echo canceller It does not match the propagation path of the voice after the relative position between the speech force and the microphone is changed, and the echo suppression performance is degraded and the communication quality is degraded.
- the present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a communication device capable of maintaining high echo suppression performance even when the relative position between a speaker and a microphone is changed and enabling high-quality communication.
- the purpose is to provide. Disclosure of the invention
- the communication device includes a housing having a reference point, a voice output means for outputting a near-end signal as far-end voice, a voice input means for receiving near-end voice, and a voice output means for outputting the voice.
- Echo suppression means for suppressing the echo generated when the input far-end voice is input to the voice input means, wherein the voice output means comprises a first distance predetermined from the reference point.
- a far-end signal conversion unit that converts the far-end signal into the far-end voice.
- the voice input unit is installed at a predetermined second distance from the reference point.
- a first near-end voice conversion unit that converts the input near-end voice to a first near-end signal, and is installed at a predetermined position based on the first near-end voice conversion unit, Converting the input near-end voice into a second near-end signal
- a second near-end voice conversion unit wherein the echo suppression means includes: the far-end signal conversion unit and one of the first near-end voice conversion unit or the second near-end voice conversion unit.
- a current value detection unit that detects a current value of a parameter that defines a relative position between: the far-end voice converted by the far-end signal conversion unit; The present value detection is performed based on a first function having a propagation time propagating to a conversion section as a dependent variable and a second function having a propagation time propagating to the second near-end speech conversion section as a dependent variable.
- a first propagation time calculating unit that calculates the first propagation time and the second propagation time corresponding to the current value detected by the unit, and a first propagation time calculating unit that calculates the first propagation time and the second propagation time.
- D that is changed according to the first propagation time and the second propagation time Echo has a configuration including a first suppression after the near-end signal output unit for outputting a first near-end signal after suppression which is suppressed by over suppression characteristics.
- the first post-suppression near-end signal output unit calculates the first near-end signal converted by the first near-end voice conversion unit into the first propagation time.
- a first near-end signal delay unit that delays based on the first propagation time calculated by the unit; and a second near-end signal converted by the second near-end voice conversion unit.
- a second near-end signal delay unit that delays based on the second propagation time calculated by the propagation time calculation unit, and a first delayed near-end signal delayed by the first near-end signal delay unit And a first output unit for outputting a difference between the second delayed near-end signal delayed by the second near-end signal delay unit.
- the echo suppression unit may further include: a frequency distribution of the first post-suppression near-end signal output from the first post-suppression near-end signal output unit; It has a configuration provided with a first equalizer that equalizes to an equalization characteristic corresponding to the detected current value.
- the echo suppression unit may be configured to convert the first near-end signal converted by the first near-end voice conversion unit and the second near-end voice conversion unit by the second near-end voice conversion unit.
- a first near-end position that is a position of the near-end relative to one of the first near-end sound conversion unit or the second near-end sound conversion unit
- a first near-end person position detecting unit that detects a near-end person position
- Second equalization for equalizing characteristics corresponding to the current value detected by the value detection unit and the first near-end person position detected by the first near-end person position detection unit And a part.
- the echo suppression means may include a current position of the near end based on the far end signal conversion unit based on the current value detected by the current value detection unit.
- a second near-end person position detecting unit that detects a second near-end position that is a position, and a frequency of the first post-suppression near-end signal output from the first post-suppression near-end signal output unit.
- a third equalizer is a third equalizer.
- the communication device includes: a housing having a reference point; audio output means for outputting a far-end signal as far-end audio; audio input means for receiving near-end audio; And echo suppression means for suppressing echo generated when the far-end voice output from the voice input means is input to the voice input means, wherein the voice output means includes a first predetermined voice signal from the reference point.
- a far-end signal converter for converting the far-end signal into the far-end voice, the voice input means being disposed at a second predetermined distance from the reference point;
- a first near-end speech converter for converting the input near-end speech into a first near-end signal, and a first near-end speech converter provided at a predetermined position based on the first near-end speech converter.
- the input near-end voice is converted to a second near-end signal
- a second near-end audio converter for converting, the echo suppressing means is any one of the far-end signal converter and the first near-end audio converter or the second near-end audio converter.
- a current value detection unit that detects a current value of a parameter that defines a relative position between the first and the second near-end voice conversion units, wherein the parameter is an independent variable, and the near-end voice propagates to the first near-end voice conversion unit.
- a third function having a third propagation time as a dependent variable and a fourth function having a fourth propagation time at which the near-end speech propagates to the second near-end speech converter as a dependent variable.
- a second propagation time calculator that calculates the third propagation time and the fourth propagation time corresponding to the current value detected by the current value detector. Is changed according to the third propagation time and the fourth propagation time calculated in A residual voice signal extraction unit for extracting a residual voice signal according to the residual voice signal extraction characteristic, the first near-end signal converted by the first near-end voice conversion unit, and the second near-end The residual audio signal extracted by the residual audio signal extraction unit is subtracted from one of the second near-end signals converted by the audio conversion unit to obtain a second suppressed near-end signal. And a second post-suppression near-end signal output unit.
- the residual voice signal extraction unit calculates the first near-end signal converted by the first near-end voice conversion unit by the second propagation time calculation unit.
- a third near-end signal delay unit that delays based on the third propagation time, and the second near-end signal converted by the second near-end speech conversion unit is converted to the second propagation time.
- a fourth near-end signal delay unit that delays based on the fourth propagation time calculated by the calculation unit; a third delayed near-end signal delayed by the third near-end signal delay unit; A residual audio signal output unit that outputs a difference between the fourth delayed near-end signal delayed by the fourth near-end signal delay unit as a residual audio signal, and the second post-suppression near-end signal output unit Is based on the residual audio signal output from the residual audio signal output unit, Signals other than the signal corresponding to the near-end audio included in either the converted first near-end signal or the second near-end signal converted by the second near-end audio converter A disturbing sound signal estimating unit for estimating the disturbing sound signal, and the first near-end signal converted by the first near-end sound converting unit or converted by the second near-end sound converting unit.
- a fifth near-end signal delay unit that delays one of the second near-end signals by a time required for estimating the interfering sound signal in the interfering sound signal estimating unit; and a fifth near-end signal delaying unit.
- An output unit, and the disturbing sound signal estimation characteristic of the disturbing sound signal estimating unit is changed to the second suppressed near-end signal.
- Square time average has a structure comprising an update unit which sequentially updates the optimum disturbing sound signal estimation properties that make minimum.
- the echo suppression means may include an initial characteristic for setting an initial interference sound signal estimation characteristic of the updating unit in accordance with the current value detected by the current value detection unit. It has a configuration including a setting unit.
- the disturbing sound signal estimation characteristics of the disturbing sound signal estimating unit quickly converge to the optimum disturbing sound signal estimation characteristics for minimizing the mean squared value of the near-end signal after suppression. Be suppressed.
- the echo suppression unit may be configured to convert the first near-end signal converted by the first near-end voice conversion unit and the second near-end voice conversion unit by the second near-end voice conversion unit. From the cross-correlation function with the second near-end signal, the first near-end voice conversion unit or the second near-end voice conversion unit is the position of the near-end person with respect to one of the first near-end voice conversion unit A first near-end person position detecting unit for detecting the near-end position of the second end, and a frequency distribution of the second post-suppression near-end signal output from the second post-suppression near-end signal output unit. A second equalization that equalizes to an equalization characteristic corresponding to the current value detected by the current value detection unit and the first near end position detected by the first near end person position detection unit. Part.
- the echo suppression means is based on the current value detected by the current value detection unit, and is a position of the near end relative to the far end signal conversion unit.
- a second near-end position detecting unit that detects a second near-end position, and a frequency distribution of the second post-suppression near-end signal output from the second post-suppression near-end signal output unit,
- a third equalization for equalizing to an equalization characteristic corresponding to the current value detected by the current value detection unit and the second near-end person position detected by the second near-end position detection unit Part.
- the second near-end position detection unit Is simpler than the configuration of the first near end position detection unit.
- the communication device includes: a housing having a reference point; audio output means for outputting a far-end signal as far-end audio; audio input means for receiving near-end audio; And echo suppression means for suppressing echo generated when the far-end voice output from the voice input means is input to the voice input means, wherein the voice output means includes a first predetermined voice signal from the reference point.
- a far-end signal converter that is installed at a distance and converts the far-end signal into the far-end voice
- the voice input means is a second predetermined from the reference point
- a first near-end audio converter that is installed at a distance and converts the input near-end audio to a first near-end signal
- a predetermined near-end audio converter that is based on the first near-end audio converter.
- a second near-end audio converter that is installed at a position where the input is near-end and converts the input near-end audio into a second near-end signal
- the echo suppression unit includes a first near-end audio converter.
- the first near-end signal and the second near-end signal based on the first near-end signal converted by the second near-end signal conversion unit and the second near-end signal converted by the second near-end voice conversion unit.
- An echo component detection unit that detects an echo component signal that is a signal other than the signal corresponding to the genuine near-end voice included in common with the near-end signal; and the first near-end voice converter converted by the first near-end voice conversion unit From one of the near-end signal and the second near-end signal converted by the second near-end voice converter,
- a third post-suppression near-end signal output unit that subtracts the echo component signal detected by the echo one-component detection unit and outputs a third post-suppression near-end signal.
- the echo component signal means a signal other than the signal corresponding to the near-end voice, and includes not only the echo in the near-end signal but also a signal corresponding to any noise such as background noise.
- the echo component detection unit may be configured to convert the first near-end signal converted by the first near-end voice conversion unit and the second near-end voice conversion unit
- a true near-end speech estimating unit for estimating a true near-end signal corresponding to a true near-end speech commonly included in the second near-end signal; Either a first near-end signal or the second near-end signal converted by the second near-end speech converter is used for the true near-end signal estimation in the true near-end speech estimator.
- a sixth near-end signal delay unit that delays by time, a sixth delayed near-end signal that is the near-end signal delayed by the sixth near-end signal delay unit, and an estimation by the true near-end speech estimation unit.
- the difference between the genuine near-end signals thus obtained is defined as a first echo component signal that is a signal other than the genuine near-end signal.
- An echo component signal output unit that outputs the first near-end voice based on the echo component signal output from the echo component signal output unit.
- the first near-end signal converted by the conversion unit or the second near-end signal converted by the second near-end voice conversion unit And a first near-end speech conversion unit for estimating a second echo one-component signal that is a signal other than the signal corresponding to the near-end speech included in one of the signals.
- the echo signal in the echo component estimation unit Either the first near-end signal or the second near-end signal converted by the second near-end voice conversion unit, the echo signal in the echo component estimation unit A seventh near-end signal delay unit that delays by a time required for estimating the component, and a signal from the seventh delayed near-end signal that is the near-end signal delayed by the seventh near-end signal delay unit.
- a third output unit that subtracts the second echo component signal estimated by the component estimation unit and outputs a third post-suppression near-end signal.
- an echo component signal that is a signal other than the signal corresponding to the near-end voice is extracted, and the extracted echo component signal is subtracted from the near-end signal. Even when the relative position with respect to the voice converter changes, echo and background noise in the near-end signal are suppressed, and a communication device capable of high-quality communication can be realized.
- the communication device of the present invention may further include: a first near-end signal converted by the first near-end voice conversion unit and a second near-end signal converted by the second near-end voice conversion unit.
- a first adaptive filter that performs adaptive filter processing so as to minimize the absolute value of the signal output from the echo component output unit for any one of the echo component output units;
- a second adaptive filter that performs adaptive filter processing on the echo component signal output from the first component signal output unit so as to minimize the absolute value of the signal output from the third output unit.
- the echo suppression means may include a parameter for defining a relative position between the far-end signal converter and one of the first near-end audio converter or the second near-end audio converter.
- a current value detection unit for detecting a value and the current value detection unit A first initial value determining unit that determines an initial value of a first filter coefficient, which is a parameter of the adaptive filter processing performed by the first adaptive filter, according to the current value of the output parameter; And a second initial value determining unit that determines an initial value of a second filter coefficient which is a parameter of the adaptive filter processing performed by the second adaptive filter according to the current value of the parameter detected by the second adaptive filter. are doing.
- the first initial value determining unit and the second initial value determining unit perform the first filter counting and the second filter counting according to the current position of the parameter detected by the current detecting unit.
- the far-end sound becomes the near-end sound in a short time.
- the echo and background noise in the near-end signal generated by the mixing are suppressed, and a communication device capable of high-quality communication can be realized.
- the echo suppression unit may be configured such that when a predetermined near-end signal of the first near-end signal or the second near-end signal is more prominent than the far-end signal. And instructing the first adaptive filter to update the first filter coefficient, and wherein the far-end signal is a predetermined near-end signal of the first near-end signal or the second near-end signal.
- the second adaptive filter includes an adaptive control unit that instructs the second adaptive filter to update the second filter coefficient when the second adaptive filter is superior to the end signal. With this configuration, the adaptive control unit instructs the first adaptive filter and the second adaptive filter to update the first filter count and the second filter coefficient based on the far-end signal and the near-end signal.
- FIG. 1 is a functional configuration diagram of a communication device according to a first embodiment of the present invention.
- FIG. 2 is a hardware configuration diagram of the communication device according to the first embodiment of the present invention.
- FIG. 3 is a configuration diagram when the communication device according to the present invention is applied to a mobile phone.
- FIG. 4 is a flowchart illustrating the operation of the communication device according to the first embodiment of the present invention.
- FIG. 5 is a functional configuration diagram of the communication device according to the first embodiment including a first equalization unit.
- FIG. 6 is a flowchart illustrating the operation of the communication apparatus according to the first embodiment including the first equalizing unit.
- FIG. 7 is a flowchart illustrating the operation of the first equalizer of the communication device according to the first embodiment.
- FIG. 8 is a graph showing the equalization characteristics of the first equalizer of the communication device according to the first embodiment.
- FIG. 9 is a functional configuration diagram of the communication device according to the first embodiment including a second equalizer.
- FIG. 10 is a flowchart for explaining the operation of the communication apparatus according to the first embodiment including the second equalizer.
- FIG. 11 is a flowchart for explaining the operation of the second equalizer of the communication device according to the first embodiment.
- FIG. 12 is a functional configuration diagram of the communication device of the first embodiment including the third equalizer of the communication device of the first embodiment.
- FIG. 13 is a graph showing the equalization characteristics of the third equalization unit of the communication device according to the first embodiment.
- FIG. 14 is a functional configuration diagram of the communication device according to the second embodiment of the present invention.
- FIG. 15 is a flowchart illustrating the operation of the communication device according to the second embodiment of the present invention.
- FIG. 16 is a flowchart for explaining the operation of the echo suppressing means of the communication device according to the second embodiment of the present invention.
- FIG. 17 is a functional configuration diagram of the communication device of the second embodiment including an initial characteristic setting unit.
- FIG. 18 is a flowchart for explaining the operation of the communication apparatus according to the second embodiment including an initial characteristic setting unit.
- FIG. 19 is a functional configuration diagram of the communication device of the second embodiment including the second equalizer.
- FIG. 21 is a functional configuration diagram of a communication device of a second embodiment including a third equalizer.
- FIG. 21 is a block diagram of a communication device of a third embodiment according to the present invention. It is a figure
- FIG. 23 is a flowchart illustrating the operation of the communication device according to the third embodiment of the present invention.
- FIG. 24 is a diagram illustrating an effect obtained by the communication device according to the third embodiment of the present invention.
- FIG. 25 is a configuration diagram of a conventional telephone device.
- FIG. 26 is a configuration diagram of a conventional telephone device. BEST MODE FOR CARRYING OUT THE INVENTION
- the “reference point” is a reference that defines a relative position between the far-end signal conversion unit and one of the first near-end sound conversion unit and the second near-end sound conversion unit.
- a hinge connecting the two partial housings is a reference point.
- the “reference position” is a position of a near-end person with reference to one of the far-end signal conversion unit, the first near-end sound conversion unit, and the second near-end sound conversion unit. It is determined at the design stage, assuming normal use conditions.
- a reference position based on one of the first near-end voice converter and the second near-end voice converter is the first reference position
- a reference position based on the far-end signal converter is the second reference position. This is the second reference position.
- the communication device includes a voice output unit 11 that outputs a far-end signal as far-end voice, and a voice input unit that receives near-end voice. 12 and an echo suppressing means 13 for suppressing an echo generated when the far-end voice output from the voice output means 11 is input to the voice input means 12.
- the audio output unit 11 includes a far-end signal conversion unit 112 that is installed at a predetermined first distance from the reference point and converts a far-end signal into far-end audio.
- the voice input means 12 is provided at a second predetermined distance from the reference point, and converts the input near-end voice into a first near-end signal.
- 2 1 and 1 A second near-end audio converter 1 2 2 which is installed at a predetermined position based on the near-end audio converter 1 2 1 and converts the input near-end audio to a second near-end signal. including.
- the echo suppression means 13 is a relative position between the far-end signal converter 112 and either the first near-end voice converter 121 or the second near-end voice converter 122.
- Current value detector 131 which detects the current value of the parameter defining the distance, far-end signal converter 1 12, and first near-end audio converter 1 2 1 or second near-end audio converter 1 2
- the parameter that defines the relative position with either one of the two is set as an independent variable, and the far-end speech converted by the far-end signal converter 1 1 2 propagates to the 1st near-end voice converter 1 2 1
- the first function having the dependent propagation time (hereinafter referred to as the “first propagation time”) as the dependent variable and the propagation time (hereinafter referred to as the “second propagation time”) to the second near-end speech converter 1 2 2
- the first propagation time and the second propagation time corresponding to the current value detected by the current value detection unit 13 1 based on the second function with
- the first propagation time calculating section 132 for calculating the
- the first post-suppression near-end signal output unit 130 converts the first near-end signal converted by the first near-end voice conversion unit 121 into a first propagation time calculation unit 133
- the first near-end signal delay unit 133 that delays based on the first propagation time calculated in and the second near-end signal converted by the second near-end voice converter 122 Delayed by the second near-end signal delay unit 13 4 which is delayed based on the second propagation time calculated by one propagation time calculation unit 13 2, and by the first near-end signal delay unit 13 3
- a first output section 135 for outputting a difference signal between the first delayed near-end signal obtained and the second delayed near-end signal delayed by the second near-end signal delay section 134.
- FIG. 1 shows a functional configuration of a communication device according to the first embodiment of the present invention, which includes a first near-end signal delay section 133 and a second near-end signal delay section 134.
- the propagation time of the voice from the far-end signal converter 1 1 2 to the first near-end voice converter 1 2 1 or the second near-end voice converter 1 2 2 is negligible.
- the corresponding first near-end signal delay section 133 or second near-end signal delay section 134 may be omitted.
- the signal is delayed by the first near-end signal delay unit 1333.
- First delay The difference between the extended near-end signal and the second near-end signal converted by the second near-end voice conversion unit 122 is output from the first output unit 135.
- the communication device includes the first near-end signal delay unit 133 and the second near-end signal delay unit 134
- the difference between the first delayed near-end signal delayed by the end signal delay section 133 and the second delayed near-end signal delayed by the second near-end signal delay section 134 is It is output from the output unit 135.
- the far-end signal converter 1 1 2 of the audio output unit 11 is composed of a far-end signal amplifier 2 11 and a speaker 2 12.
- the first near-end audio converter 1 2 1 of the audio input means 1 is a first microphone 2 2 1 and a first near-end signal amplifier 2 2 3
- the second near-end audio converter 1 2 Reference numeral 22 denotes a second microphone 222 and a second near-end signal amplifier 222, respectively.
- the echo current value detecting unit 1 3 1 suppression means 1 3, the far-end signal converting unit 1 1 2 and the first near-end voice converting portion 1 2 1 or the second near-end voice conversion unit 1 2 2 Any detector can be used as long as it can detect a parameter that defines a relative position with respect to any one of them and convert it into an electric signal, and a mouthpiece encoder, a potentiometer, or the like can be applied.
- a parameter that defines the relative position between the far-end signal conversion unit 112 and either the first near-end audio conversion unit 121 or the second near-end audio conversion unit 122 is not necessarily required. It is not necessary to detect at least one specific relative position, and a switch in which the open / close state is reversed when at least one specific relative position is reached may be applied.
- the echo suppression means 13 detects the near-end signals output from the first near-end signal amplifier 22 3 and the second near-end signal amplifier 22 4 and the current value detection section 13 1
- An analog-to-digital converter (hereinafter simply referred to as AZD converter) that converts parameters into digital values, and a digital-to-analog converter (hereinafter simply D / A) that converts near-end signals after echo suppression to analog signals 2 3 4).
- Memory 2 3 1, CPU 2 3 2, A / D converter 2 3 3, and D / A converter 2 3 4 are connected to bus 2 3 5 It is more electrically coupled to each other.
- the current value detection unit 13 1 is configured by a switch, a digital input interface may be provided, and the current value may be read via the digital input interface.
- the first propagation time in the echo suppression means 13 when the communication device according to the present invention is applied to a mobile phone having a housing composed of two partial housings It defines the relative position between the far-end signal converter 1 1 2 used in the calculator 1 3 2 and the first near-end audio converter 1 2 1 or the second near-end audio converter 1 2 2
- the parameters are set as independent variables, and the sound output from at least one far-end signal converter 1 1 2 is converted into the first near-end sound converter 1 2 1 and the second near-end sound converter 1 2 2 respectively.
- a specific example of a function whose propagation time is a dependent variable will be described.
- a mobile phone 30 composed of a casing composed of two partial casings has a first partial casing 32 and a second partial casing 3 connected by a hinge 31 which is a substantially central reference point.
- the first partial housing 3 2 is provided with the speed force 2 12 included in the far-end signal converter 1 1 2, and the second partial housing 3 3 is provided with the first near-end audio
- the first microphone 221 included in the converter 122 and the second microphone 222 included in the second near-end voice converter 122 are stored.
- the angle 0 is equal to the speaker 2 1 2 and the first microphone 2 2 1 and This is a parameter that defines a relative position between the second microphone 222 and one of the second microphones.
- Time T 1 required for sound to propagate from speaker 2 1 2 to first microphone 2 2 1, and sound propagates from speaker 2 1 2 to second microphone 2 2 2 The time T2 required to determine the relative position between the speaker 21 and one of the microphones 22 1 and 22 2 is defined by the equations (1) and (2), respectively.
- equation 1 As a function of the angle 6 [Equation 1]
- T, ia + b z + 2ab- cos0 / v (1)
- step S401 it is determined whether a call termination condition is satisfied, such as an on-hook state, etc. (step S401). If it is determined that the call termination condition is satisfied, the echo suppression means 13 is determined. Ends the operation. Conversely, if it is determined that the call termination condition is not satisfied, it is determined that the call is in progress, and the call is started based on whether or not the level of the near-end signal is equal to or higher than a predetermined level. It is determined whether or not the operation has been performed (step S402). Next, if it is determined in step S402 that the call has not been started, the process returns to the determination (step S401) of whether or not the call termination condition is satisfied.
- a call termination condition such as an on-hook state, etc.
- step S402 when it is determined in step S402 that the call has started, the far-end signal conversion unit 112 and the first near-end voice conversion unit 1 detected by the current value detection unit 13 1 2
- the current value of the parameter defining the relative position to either the 1 or 2nd near-end voice converter 1 2 2 is sent from the current value detector 1 3 1 via the AZD converter 2 3 3. Is read (step S403).
- a parameter defining a relative position between the far-end signal conversion unit 112 and either the first near-end voice conversion unit 121 or the second near-end voice conversion unit 122 is calculated.
- the first propagation time and the second propagation time corresponding to the current value are calculated by substituting the current value read in step (step S404). This processing corresponds to the operation of the first propagation time calculation unit 132.
- the near-end signal is divided into a first near-end sound converter 2 2 3 and a second near-end sound converter 2 2 4 is read via the AZD converter 233 (step S405), and the near-end signal is delayed by the propagation time (step S406).
- the delay section may be configured with a FIR (finite impulse response) filter.
- This processing corresponds to the operation of the first near-end signal delay unit 133 and the second near-end signal delay unit 134.
- step S407 This processing corresponds to the operation of the first output unit 135.
- step S406 to step S408 corresponds to the operation of the first post-suppression near-end signal output unit 130.
- the suppressed near-end signal is converted into an analog signal by the D / A converter 234 and output (step S408).
- step S409 it is determined whether or not the call is terminated based on whether or not the level of the near-end signal is lower than a predetermined level (step S409), and the level of the near-end signal is determined in advance. If it is determined that the call has not ended at the level higher than or equal to the specified level, the process returns to the reading of the near-end signal (step S405). Conversely, when it is determined that the call is terminated when the level of the near-end signal is lower than or equal to the predetermined level, whether the call termination condition is satisfied is determined by whether the terminal is in an on-hook state or the like. The process returns to the determination (step S401).
- the first propagation time calculated by the first propagation time calculation unit 132 is defined as the delay time of the first near-end signal delay unit 133, and the first propagation time calculation unit 1
- the second propagation time calculated in 32 is set as the delay time of the second near-end signal delay unit 134.
- one of the far-end signal conversion unit 112 and the first near-end voice conversion unit 121 or the second near-end voice conversion unit 122 (for example, the first near-end voice conversion unit)
- the transmission time of the voice to the section 1 2 1) is fixed delay time, and the far-end signal conversion section 1 1 2 It is desirable to separately set the difference between the propagation time of the sound to the second unit (for example, the second near-end sound conversion unit 122) and the fixed delay time as a variable delay time.
- the relative position of the far-end signal converter 112 and one of the first near-end voice converter 122 or the second near-end voice converter 122 during a call can be assumed in advance. Not only can the delay time be fixed to a predetermined time, but also the case where the positional relationship between the audio output means 11 and the audio input means 12 is changed and the variable delay time becomes negative This is because it is easy.
- the communication device includes a current value detection unit 131, a first propagation time calculation unit 132 in the echo suppression unit 13, Since one near-end signal delay section 13 3 and second near-end signal delay section 13 4 and first output section 13 5 are provided, the current far-end signal conversion section 1 1 2 Even if the relative position between either the first near-end speech converter 122 or the second near-end speech converter 122 is changed, the echo is reliably suppressed. It is possible to do.
- the communication apparatus includes an echo suppression unit 13 that includes a first post-suppression near-end signal output unit 130,
- the frequency distribution of the first post-suppression near-end signal output from the first post-suppression near-end signal output unit 130 is changed to an equalization characteristic corresponding to the current value detected by the current value detection unit 1331.
- a first equalization unit 13 6 for equalization may be provided.
- FIG. 6 is a flowchart for explaining the operation of the echo suppression means 13 including the first equalization section 1336.
- the frequency distribution of the near-end signal after suppression is equalized.
- the operation of the first equalizer 1336 (step S4100) to be performed is added.
- the operation of the first equalizing unit 1336 is realized by executing a program stored in the memory 231.
- step S401 to step S407 the processing from step S401 to step S407, and the processing after step S408 are the same as those in FIG. 4, and a description thereof will be omitted.
- the operation of the first equalizer 1336 will be described with reference to the flowchart of FIG. 7.
- the current value The equalization characteristic corresponding to the current value detected by the detection unit 13 1 is stored in the memory 2 31 in advance.
- the calculation is performed using the equalization characteristics (step S411), and the frequency distribution of the near-end signal is equalized (step S412).
- the above processing corresponds to the operation of the first equalizing unit 1336.
- FIG. 8 the operation of the first equalizer 1336 when the communication device according to the present invention is applied to a mobile phone having a housing composed of two partial housings will be described. explain. FIG.
- the solid line, the dashed line, and the broken line show the case where the angle 0 formed by the first partial housing 32 with respect to the second partial housing 33 is 0 degrees, 30 degrees, and 60 degrees, respectively.
- the data of this graph is stored in the memory 231 in advance.
- the current value detection unit 13 1 detects that the angle 0 formed by the first partial housing 32 with respect to the second partial housing 33 is 30 degrees, Is selected, and using this equalization characteristic, the frequency distribution of the first post-suppression near-end signal output from the first output section 135 is equalized.
- the angle detected by the current value detection unit 13 1 is an angle that is not stored in the memory in advance such as 0 force, for example, 45 degrees, it corresponds to the stored angle close to that angle.
- the equalization characteristic is calculated from the equalization characteristic by an interpolation method or the like.
- the equalization characteristic changes in the subsequent stage of the first post-suppression near-end signal output unit 130 according to the current value detected by the current value detection unit 1331 Since the first equalizer 1336 is provided, the communication quality deteriorates even if the relative position between the audio output means 11 and the audio input means 12 changes and the frequency distribution of the near-end signal after suppression deteriorates. Can be prevented.
- the echo suppressing means 13 includes a first near-end voice conversion section 122 and a second near-end voice conversion section.
- a first near-end position detecting unit 13 that detects the position of the near end from a cross-correlation function between the first near-end signal and the second near-end signal output from the unit 122 7, the frequency distribution of the first post-suppression near-end signal output from the first post-suppression near-end signal output unit 130 is the current value detected by the current value detection unit 131, and
- a second near-equalizer 1 38 for equalizing to an equalization characteristic corresponding to the first near-end position detected by the first near-end position detector 13 7; .
- FIG. 10 is a flowchart for explaining the operation of the echo suppressor 13 including the second equalizer 1338.
- a second equalization process (step S420) for equalizing the frequency distribution of the suppressed near-end signal is added to the flowchart of FIG. Note that the processing from step S401 to step S407, and the processing after step S408 are the same as those in FIG. 4, and a description thereof will be omitted.
- a non-signal section in which the far end does not speak is detected. This detection is generally made based on whether or not the level of the far-end signal is equal to or less than a fixed threshold.However, when noise is superimposed on the far-end signal, the threshold is determined. The average value of the far-end signal at a predetermined time may be used.
- the whitening cross-correlation function It is advantageous to determine whether the maximum value is equal to or greater than the reference value (0.5 to 0.7).
- the whitening cross-correlation function is defined as the first near-end signal converted by the first near-end audio converter 121 and the second near-end signal converted by the second near-end audio converter 122.
- the cross vector between the near-end signal of the first near-end signal and the power of the first near-end signal converted by the first near-end sound conversion unit 121 and the second near-end sound conversion unit 1 2 2 This is a function that has been normalized by the product of the power of the second near-end signal converted by and inverse Fourier transformed.
- the first near end signal and the second near end already read from the first near end speech converter 121 are read.
- the first near-end audio converter 1 2 1 or the second near-end audio converter 1 2 2 is obtained by the whitening cross-correlation function between the second near-end signals read from the audio converter 1 2 2.
- the first near end position which is the position of the near end based on either one of the above, is calculated (step S 4 21). This processing corresponds to the operation of the first near-end person position detection unit 1337.
- the first near-end person position detected by the first near-end position detection unit 1337 and the equalization characteristic corresponding to the current value detected by the current value detection unit 13 1 are stored in the memory 2 in advance.
- 31 is calculated using the equalization characteristics stored in step 1 (step S422), and the frequency distribution of the near-end signal after suppression is equalized using this equalization characteristic (step S42). 3).
- the above processing is This corresponds to the operation of the second equalizing section 1338.
- the first near end position detecting section 1337 and the second equalizing section 1338 are provided in the echo suppression means 13, so that the first Even if the near end position of the near end deviates from the first reference position, the communication quality is prevented from deteriorating by equalizing the frequency distribution of the near end signal after suppression with the equalization characteristics according to the deviation. It is possible to do.
- the communication device based on the current value detected by the current value detection unit 131, the far-end signal conversion unit 112 A second near-end position detection unit 13 9 that detects a second near-end position, which is the current position of the near end, based on the first near-end signal output unit 13 0
- a third equalizing section 140 for equalizing to an equalizing characteristic corresponding to the near end position of the third person.
- the near-end person is assumed to be located at the second reference position based on the far-end signal conversion unit 112 opposite to the far-end signal conversion unit 112, and the equalization is performed.
- the characteristics are calculated.
- the near end receives an angle ⁇ (see FIGS. 3 and 1) with respect to the second partial housing 33. (See 2).
- the angle ⁇ and the near-end audio Propagation time that propagates to the first near-end voice conversion unit 1 2 1 and the 'second near-end voice conversion unit 1 2 2 It is a function of the angle ⁇ formed. Therefore, from the current value detected by the current value detection unit 131, the angle near-end speech is propagated to the first near-end speech conversion unit 1 2 1 and the second near-end speech conversion unit 1 2 2. Can be calculated.
- the dashed line, the broken line and the solid line in each graph represent the case where the angles formed by the near end with respect to the second partial housing 33 are 90 degrees, 120 degrees and 150 degrees, respectively.
- the frequency distribution of the near-end signal after suppression is shown.
- the angle 0 formed by the first partial housing 32 with respect to the second partial housing 33 which is the current value detected by the current value detection unit 13 1 is 30 degrees
- the frequency distribution of the suppressed near-end signal is equalized using this equalization characteristic.
- the equalization characteristics are not stored in the memory 231 in advance, the equalization characteristics are stored using the stored equalization characteristics by interpolation or the like. Can be calculated.
- the second near end position detecting section 13 9 and the third equalizing section 140 are provided in the echo suppressing means 13, the near end Even if the user position deviates from the second reference position, it is possible not only to prevent the call quality from deteriorating but also to simplify the configuration of the second near-end position detection section 1339. Become.
- the communication device comprises: a voice output unit 11 for outputting a far-end signal as far-end voice; a voice input unit 12 for receiving near-end voice; and a voice output unit. And echo suppression means for suppressing echo generated when the far-end voice output from the voice input means is input to the voice input means.
- the audio output unit 11 includes a far-end signal conversion unit 112 that is installed at a predetermined first distance from the reference point and converts a far-end signal into far-end audio.
- the voice input means 12 is provided at a second predetermined distance from the reference point, and converts the input near-end voice into a first near-end signal.
- 21 and a second near-end audio converter that is installed at a predetermined position based on the first near-end audio converter 1 21 and converts the input near-end audio to a second near-end signal Parts 1 and 2 are included.
- the echo suppression means 13 comprises a far-end signal converter 1 1 2 and a first near-end voice converter 1 2 1 or Is a current value detector 131, which detects the current value of a parameter that defines a relative position with respect to one of the second near-end voice converters 122, Is a third function with the third propagation time propagating to the first near-end speech converter 122 as the dependent variable, and the fourth function where the near-end speech is propagated to the second near-end speech converter 122.
- a second propagation time that calculates a third propagation time and a fourth propagation time corresponding to the current value detected by the current value detection unit 131 based on a fourth function that uses the propagation time of The residual audio signal is extracted from the residual audio signal extraction characteristics that are changed according to the third propagation time and the fourth propagation time calculated by the calculation unit 141 and the second propagation time calculation unit 141.
- the first near-end signal converted by the first near-end sound converter 121 and the second near-end signal The near-end speech converter in which the residual speech signal extracted by the residual speech signal extraction unit 150 is subtracted from one of the second near-end signals converted by the speech conversion unit 122 to suppress the residual speech And a second post-suppression near-end signal output unit 151 that outputs the second post-suppression near-end signal. Then, the residual audio signal extracting unit 150 converts the first near-end signal converted by the first near-end audio converting unit 121 into the third near-end signal calculated by the second propagation time calculating unit 141.
- a third near-end signal delay unit that delays based on the propagation time of the second near-end signal, and a second propagation time calculation unit that converts the second near-end signal converted by the second near-end voice conversion unit 122 into a second near-end signal
- the fourth near-end signal delay section 1443 that is delayed based on the fourth propagation time calculated in 141, and the third near-end signal delay section 144 that is delayed by the third near-end signal delay section 142
- a residual audio signal output section 144 for outputting a difference between the delayed near-end signal and the fourth delayed near-end signal delayed by the fourth near-end signal delay section 144 as a residual audio signal.
- the second post-suppression near-end signal output section 151 is converted by the first near-end audio conversion section 121 based on the residual audio signal output from the residual audio signal output section 144.
- the signal is a signal other than the signal corresponding to the near-end audio included in either the converted first near-end signal or the second near-end signal converted by the second near-end audio converter 122.
- a disturbing sound signal estimating unit for estimating a disturbing sound signal, a first near-end signal or a second near-end sound converting unit converted by the first near-end sound converting unit.
- a fifth near-end signal delay unit 144 that delays one of the second near-end signals converted in step by the time required for estimating the interfering sound signal in the interfering sound signal estimating unit Subtracting the disturbing sound signal estimated by the disturbing sound signal estimating unit 145 from the fifth delayed near-end signal, which is the near-end signal delayed by the near-end signal delaying unit 146 of FIG.
- the second output section 1 4 7 for outputting a near-end signal after suppression, interference sound signal estimation unit 1 4 5 interference sound
- An updating unit 148 for sequentially updating the signal estimation characteristic to an optimal interference sound signal estimation characteristic that minimizes the squared time average value of the second suppressed near-end signal.
- the propagation time required for the near-end speech to propagate to the first near-end speech converter 1 2 1 and the second near-end speech converter 1 2 2 Is calculated (step S430). This is because if the near-end person is located at the second reference position, which is a position separated by a predetermined distance in front of the far-end signal conversion unit 112, the near-end sound will The propagation time propagating to one near-end voice converter 1 2 1 and the second near-end voice converter 1 2 2 is calculated by the first near-end voice converter 1 2 1 or the second near-end voice converter. This is because the angle can be expressed as a function of the angle 0 formed by the sound output means 11 with respect to either one of 1 and 2. This processing corresponds to the operation of the second propagation time calculation unit 141.
- the propagation time for the near-end voice to propagate to the first near-end voice conversion unit 122 and the second near-end voice conversion unit 122 is the first near-end person position in the first embodiment. It may be calculated by the whitening cross-correlation function already described as the operation of the detector 1337, but immediately after the near-end starts to speak, the propagation time is not sufficiently estimated and the communication quality may be degraded. There is.
- the propagation time is calculated assuming that the near end is located at the second reference position, if the near end is located at a position shifted from the second reference position, the call quality will be degraded. Therefore, when the near end is not speaking, the near end calculates the propagation time as being located at the second reference position, and otherwise calculates the propagation time based on the whitening cross-correlation function. It may be issued.
- the near-end signals are read from the first near-end signal amplifier 222 and the second near-end signal amplifier 222 through the AZD converter 233 (step S405), and the echo and Background noise is suppressed (step S440).
- step S408 is the same as the operation of the echo suppression unit of the first embodiment, and a description thereof will be omitted.
- step S440 of the second embodiment will be described with reference to FIG. 16.
- the near-end person's voice is converted to the first near-end voice conversion unit 122 and the second
- the near-end signal is delayed according to the propagation time before the signal propagates to the near-end voice conversion unit 122 (step S444).
- This processing corresponds to the operation of the third near-end signal delay section 142 and the fourth near-end signal delay section 144.
- step S4442 by taking the difference between the first delayed near-end signal, which is the near-end signal delayed by the third near-end signal delay section 1442 and the fourth near-end signal delay section 144, The voice of the near-end person included in the near-end signal is deleted, and the residual voice signal is output (step S4442). Note that this processing corresponds to the operation of the residual audio signal output unit 144.
- a well-known adaptive filter responds to the interfering sound in which the far-end voice and the background noise included in the first near-end signal or the second near-end signal are mixed.
- a disturbance sound signal which is a signal to be changed, is estimated (step S444). This processing corresponds to the operation of the disturbance sound signal estimation unit 144.
- one of the first near-end signal and the second near-end signal for example, the first near-end signal converted by the first near-end voice conversion unit 121 is converted into an interference sound signal estimation unit 1
- the processing is delayed by a time corresponding to the processing time required for estimating the disturbing sound signal (step S444). This processing corresponds to the operation of the fifth near-end signal delay unit 146.
- step S445 the interfering sound signal is subtracted from the delayed near-end signal, and a suppressed near-end signal in which echo and background noise are suppressed is output (step S445).
- This processing corresponds to the operation of the second output unit 147.
- Step S444 This processing corresponds to the operation of the disturbance sound signal estimation characteristic updating unit 148.
- FRLS Fast Recursive Least Squares
- the communication apparatus includes a current value detection unit 131, a second propagation time calculation unit 141, an echo suppression unit 13, Third near end signal delay Extension section 14 2 and fourth near-end signal delay section 14 3, residual audio signal output section 1 4 4, disturbing sound signal estimation section 1 4 5, and fifth near-end signal delay section 1 4 6, a second output unit 147, and an update unit 148, so that the current far-end signal conversion unit 112, the first near-end voice conversion unit 121, and the second
- the echo and background noise generated by mixing the near-end speech contained in the near-end signal with the far-end speech in accordance with the relative position between the two near-end speech converters 122 can be reliably suppressed. It becomes possible.
- the echo suppression means 13 updates the echo in accordance with the current value detected by the current value detection section 13 1.
- An initial characteristic setting section 149 for setting the initial disturbance sound signal estimation characteristic of the section 148 may be included.
- step S401 to step S430 the operation of the echo suppression means 13 including the initial characteristic setting section 149 will be described.
- the processing from step S401 to step S430 is performed in the second embodiment. Since it is the same as the echo suppression means 13 of FIG.
- the current value is detected by the current value detection unit 131 based on the initial disturbance sound signal estimation characteristics stored in the memory 231 in advance.
- the initial disturbing sound signal estimation characteristic corresponding to the current value is calculated and set as the initial value of the disturbing sound signal estimating characteristic of the updating section 148 (step S431). This processing corresponds to the operation of the initial characteristic setting unit 149. If the initial disturbing sound signal estimation characteristic corresponding to the present value detected by the present value detecting unit 13 1 is not stored in the memory 231, the initial disturbing sound previously stored in the memory 23 1 is used. Based on the signal estimation characteristics, the initial disturbing sound signal estimation characteristics are calculated by interpolation or the like.
- step S405 is the same as that in the flowchart of FIG.
- the interference sound estimation characteristic of the interference sound signal estimation section 144 is quickly suppressed, and the near-end signal of the near-end signal is suppressed. It is possible to converge to the optimum disturbing sound signal estimation characteristic that minimizes the mean square time value, and it is possible to more reliably suppress echo and background noise.
- the echo suppression means 13 includes a first near-end voice conversion section 122 From the cross-correlation function between the one near-end signal and the second near-end signal converted by the second near-end voice converter 122, the first A first near end that detects a first near end position that is a position of the near end based on one of the near end speech conversion unit 1 2 1 and the second near end speech conversion unit 1 2 2
- the current value detector 1331 detects the frequency distribution of the second post-suppression near-end signal output from the user position detector 1337 and the second post-suppression near-end signal output unit 151.
- a second equalizer 138 that equalizes the current value and the equalized characteristic corresponding to the first near-end position detected by the first near-end position detector 1337. May be provided.
- step S420 the flow rate between the step S440 and the step S408 is A second equalization process (step S420) is executed.
- the operation of the second equalization process (step S420) will be described with reference to the flowchart of Fig. 11.
- the speech input means based on the peak interval of the whitening cross-correlation function between the near-end signals read from the first near-end speech conversion section 122 and the second near-end speech conversion section 122, the speech input means
- the first near end position which is the position of the near end based on 1 2, is calculated (step S 4 21). This process corresponds to the operation of the first near-end person position detection unit 1337.
- the equalization characteristics corresponding to the first near-end position detected by the first near-end position detection unit 13 and the current value detected by the current value detection unit 13 1 are stored in the memory 23 in advance. Is calculated using the equalization characteristics stored in step 1 (step S 4 22), and the equalization process of the near-end signal after suppression is executed using this equalization characteristics (step S 4 2 3 ). The above two processings correspond to the operation of the second equalizing unit 138.
- the first near-end person position detecting section 13 7 and the second equalizing section 13 8 are provided in the echo suppressing means 13, so that the near-end Even if the caller position deviates from the first reference position, it is possible to prevent the call quality from deteriorating.
- the echo suppression means 13 is distant based on the current value detected by the current value detector 13 1.
- a second near-end position detection unit 13 9 for detecting a second near-end position which is a position of the near end based on the end signal conversion unit 112, and a second post-suppression near end
- the frequency distribution of the near-end signal is equalized according to the current value detected by the current value detection unit 131, and the second near-end position detected by the second near-end position detection unit 1339.
- a third equalization unit 140 for equalizing the characteristics may be provided.
- the near end is located at the second reference position directly opposite to the far end signal conversion unit 112, and the equalization characteristic is determined based on the current value detected by the current value detection unit 131. Is determined.
- the near-end person uses the sound output means 11 opposed to the sound output means 11 as a reference. It is calculated as being located at the second reference position.
- the second near end position detecting section 13 9 and the third equalizing section 140 are provided in the echo suppressing means 13, the near end Even if the user position deviates from the second reference position, the frequency distribution of the near-end voice can be maintained at the reference frequency distribution that is the frequency distribution of the near-end voice when the near-end is at the second reference position.
- the configuration of the second near-end person position detection unit 1339 can be simplified than the configuration of the first near-end position detection unit 1337.
- variable delay time set in the first propagation time calculation unit or the second propagation time calculation unit is referred to as the far-end signal conversion unit and the first near-end audio signal.
- the calculation has been described as being calculated from the geometrical positional relationship with one of the conversion unit and the second near-end voice conversion unit, the variable delay time is calculated based on the fact that the impulse signal is output from the far-end signal conversion unit. It is also possible to calculate based on the cross-correlation function of the impulse response output from the one near-end speech converter and the second near-end speech converter.
- the description of the specific configuration of the first equalizer, the second equalizer, and the third equalizer is omitted, but a well-known FIR (finite impulse response) is used.
- a filter or an IIR (infinite impulse response) filter can be applied.
- the use of the FIR filter makes it possible to set the equalization characteristics precisely, and the use of the IIR filter makes it possible to reduce the amount of calculation.
- Equalization characteristics can be determined for each frequency band using a well-known puncture filter. Furthermore, it is clear that the processing of the echo suppression means of the first and second embodiments can be executed in the time domain or in the frequency domain.
- the amount of computation can be reduced as compared with processing in the time domain, but since the audio signal is converted into the frequency domain for each frame of a predetermined time length, the frame processing is performed. A time delay corresponding to the length occurs.
- one speaker is used as the far-end signal converter, but if it can be regarded as equivalently one far-end signal converter, a plurality of speakers may be used. It is clear that the invention can be applied.
- the communication device includes a voice output unit 11 for outputting a far-end signal as far-end voice, a voice input unit 12 for receiving near-end voice, and a voice output.
- An echo suppression means 13 for suppressing an echo generated when the far-end voice output from the means 11 is input to the voice input means 12.
- the audio output unit 11 includes a far-end signal conversion unit 112 that is installed at a predetermined first distance from the reference point and converts a far-end signal into far-end audio.
- the voice input means 12 is provided at a second predetermined distance from the reference point, and converts the input near-end voice into a first near-end signal. 21 and a second near-end voice that is installed at a predetermined position based on the first near-end voice converter 121 and converts the input near-end voice into a second near-end signal And a conversion unit 122.
- the echo suppressor 13 includes a first near-end signal converted by the first near-end voice converter 12 1 and a second near-end signal converted by the second near-end voice converter 12 2. And an echo component detector 160 that detects an echo component signal other than the signal corresponding to the genuine near-end voice, which is commonly included in the first near-end signal and the second near-end signal, based on From one of the first near-end signal converted by the first near-end voice conversion unit 122 and the second near-end signal converted by the second near-end voice conversion unit 122, The echo detected by the echo component detector 160 A third post-suppression near-end signal output unit 170 that subtracts one component signal and outputs a third post-suppression near-end signal is included.
- the echo component signal means a signal other than the signal corresponding to the near-end voice, and is not limited to the echo included in the narrow-end signal in a narrow sense, but includes a signal corresponding to any noise such as background noise.
- the communication device of the present embodiment When the communication device of the present embodiment is applied to a mobile phone having a housing composed of two partial housings, as shown in FIG. 3, the communication device has a hinge 31 and a hinge 3 as shown in FIG. 1 has two partial housings 3 2 and 3 3 joined together by a hinge 31, and the opening angle ⁇ ⁇ , which is an angle formed by the two partial housings 3 2 and 3 3, can be variably changed by a hinge 31. ing .
- a display 341 may be provided in the housing.
- the direction indicated by reference numeral 352 indicates the direction of the speaker as viewed from the communication device.
- the echo component detecting section 160 is configured to convert the first near-end signal converted by the first near-end sound converting section 121 and the second near-end signal converted by the second near-end sound converting section 122.
- a true near-end speech estimator for estimating a genuine near-end signal corresponding to a genuine near-end speech commonly included in the end signal, and a first near-end converted by the first near-end speech converter 122 A sixth signal that delays one of the signal and the second near-end signal converted by the second near-end speech converter 122 by the time required for estimating the true near-end signal in the true near-end speech estimator.
- An echo component signal output unit 165 that outputs a difference between the near-end signals as a first echo component signal that is a signal other than the true near-end signal.
- the genuine near-end speech estimating unit includes a first near-end signal converted by the first near-end speech conversion unit 121 and a second near-end converted by the second near-end speech conversion unit 122.
- a first adaptive filter 163 that performs adaptive filter processing on any of the signals, and a first filter count that stores a first filter count that is a parameter of the adaptive filter processing performed by the first adaptive filter 163.
- the first adaptive filter 163 performs adaptive filter processing such that the absolute value of the differential signal output from the echo component signal output unit 165 is minimized. I do.
- the third post-suppression near-end signal output unit 170 outputs the first near-end voice conversion unit 1221 based on the echo component signal output from the echo component signal output unit 165.
- a second echo which is a signal other than the signal corresponding to the near-end voice included in one of the one near-end signal and the second near-end signal converted by the second near-end voice converter 122
- Estimate component signal An echo component estimator, and a first near-end signal converted by the first near-end voice converter 121 or a second near-end signal converted by the second near-end voice converter 122 Is delayed by a seventh near-end signal delay unit 176 that delays the time required for estimating the signal component of the echo in the echo component estimation unit, and a seventh near-end signal delay unit 176 Subtracting the second echo one-component signal estimated by the echo one-component estimator from the seventh delayed near-end signal, which is the obtained near-end signal, and outputting a third suppressed near-end signal And an output unit 1 75 of the system
- the echo component estimator includes a second adaptive filter 173 that performs adaptive filtering on the echo component signal output from the echo component signal output unit 165, and an adaptive filter that is performed by the second adaptive filter 173.
- a second coefficient storage unit 174 that stores a second filter coefficient that is a parameter of the filter processing, and the second adaptive filter 173 is output from a third output unit 175.
- the adaptive filter processing is performed so that the absolute value of the difference signal is minimized.
- the echo suppression means 13 further includes a far-end signal conversion unit 112 and a first near-end speech conversion unit 121 or a second near-end speech conversion unit.
- the current value detector 131 which detects the current value of the parameter that defines the relative position to either one of the end voice converters 1 2 2, and the current value of the parameter detected by the current value detector 131, The value of the adaptive filter processing performed by the first adaptive filter 163 according to the value
- 3 includes a second initial value determining unit 171, which determines an initial value of a second filter coefficient which is a parameter of the adaptive filter processing performed by the third unit 3.
- the echo suppression means 13 further updates the first filter coefficient when a predetermined near-end signal of the first near-end signal or the second near-end signal is superior to the far-end signal.
- the second An adaptive control unit 181 for instructing the second adaptive filter 173 to update the filter coefficient is included.
- the output signal from the second near-end voice converter 122 is input to the first adaptive filter 163.
- a first coefficient storage unit 164 is connected to the first adaptive filter 163.
- Output signal from sixth near-end signal delay section 16 6 and first adaptation The output signal from the filter 163 is input to the echo component signal output unit 165.
- the output signal from the echo component signal output unit 165 is input to the first adaptive filter 163 and the second adaptive filter 173.
- a second coefficient storage unit 174 is connected to the second adaptive filter 173 to read out the filter coefficients.
- the output signal from the seventh near-end signal delay unit 176 and the output signal from the second adaptive filter 173 are input to the third output unit 175.
- the output signal from the third output unit 175 is input to the second adaptive filter 173 and sent to the far end as an echo suppression signal.
- the hinge 31 is connected to a current value detection unit 1331 as state detection means, and the current value detection unit 131 detects a current value of a parameter such as the opening angle ⁇ ⁇ ⁇ of the hinge 31.
- the output signal of the current value detector 13 1 is input to the first initial value determiner 16 1 and the second initial value determiner 17 1.
- the output signal of the first initial value determining unit 16 1 is input to the first adaptive filter 16 3, and the output signal of the second initial value determining unit 17 1 is input to the second adaptive filter 17 3 Is done.
- the far-end signal from the far-end signal conversion unit 112 is input to the adaptive control unit 181.
- the second near-end signal from the second near-end voice converter 122 is also input to the adaptive controller 181, and the output signal of the adaptive controller 181 is supplied to the first adaptive
- the signals are output to the filter 16 3 and the second adaptive filter 17 3, respectively.
- the echo suppression means 13 determines whether or not a force that satisfies the call termination condition for terminating the operation by turning off the power of the communication device (S501) is satisfied. If it is determined, the operation is terminated. If it is determined that the condition is not satisfied, the operation is continued, and the process proceeds to step S502.
- step S501 If it is determined in step S501 that the call termination condition is not satisfied, it is determined whether or not the call has been started based on whether or not the level of the near-end signal is equal to or higher than a predetermined level. The determination is made by the echo suppression means 13 (S502). When it is determined in S502 that the call has started, the process proceeds to S503, and when it is determined that the call has not started, the process returns to step S501.
- the current shape of the housing is detected by the current value detection unit 1331 (S503).
- the shape of the current housing The shape detection is performed by detecting and calculating the opening angle 0 of the housing using the current value detection unit 13 1 connected to the hinge 31.
- the current value detection unit 13 1 may be any device that can convert the magnitude of the opening angle 0 into an electric signal, and can be realized using, for example, a rotary encoder, a variable resistor, or the like.
- the current value detection unit 13 1 is not necessarily connected to one of the far-end signal conversion unit 112 and the first near-end sound conversion unit 121 or the second near-end sound conversion unit 122. It is not necessary to continuously calculate the parameter that defines the relative position of, but the angle may be calculated discretely.
- the current value detection unit 1331 may detect only two states, such as an open state and a closed state, using a switch or the like.
- the initial value of the first filter coefficient and the initial value of the second filter coefficient are respectively determined by the first initial value determination unit 16 It is determined by the first and second initial value determining unit 171 and is set in the first adaptive filter 163 and the second adaptive filter 173 (S504).
- the first initial value determination unit 161 outputs a signal corresponding to the opening angle of the housing (hereinafter, referred to as an opening angle signal) to the first adaptive filter 1663,
- One adaptive filter 163 reads out a filter coefficient corresponding to the above-mentioned opening angle signal from the filter coefficients stored in the first coefficient storage section 164.
- the first coefficient storage unit 164 stores in advance filter coefficients corresponding to a predetermined number of opening angles, and the first adaptive filter 163 is specified by the input opening angle signal Based on the opening angle, the filter coefficient at the closest angle may be read out by the internal interpolation method or the like.
- the second initial value determination unit 171 outputs an opening angle signal corresponding to the opening angle of the housing to the second adaptive filter 173, and the second adaptive filter 173 outputs The filter coefficient corresponding to the opening angle signal is read from the filter coefficients stored in the second coefficient storage unit 174.
- the second coefficient storage unit 174 stores in advance filter coefficients corresponding to a predetermined number of opening angles, and the second adaptive filter 173 is specified by the input opening angle signal Based on the opening angle, the filter coefficient at the closest angle may be read out by interpolation or the like.
- step S506 When the initial value of the filter coefficient is determined in step S504, the near-end speech is collected by the first near-end speech converter 1 2 1 and the second near-end speech converter 1 2 2, A first near-end signal and a second near-end signal are generated (S505).
- the processing after step S506 can be performed by analog signal processing, but is generally performed by digital signal processing. . Therefore, in the following, it is assumed that the first near-end signal and the second near-end signal are converted from analog signals into digital signals by AD conversion means (not shown).
- processing after step S506 is performed by digital signal processing
- a configuration in which the communication device includes an element such as a microcomputer or a digital signal processor (DSP) is generally used.
- DSP digital signal processor
- the processing after step S506 shall be described in the program mounted on the microcomputer or the DSP.
- the first near-end signal and the second near-end signal that have been converted to digital signals are converted to the time domain or temporarily to the frequency domain, and the subsequent processing is performed.
- sample processing is performed for each sampling cycle in the AD conversion means.
- frame processing is performed to collectively process input signals in frames having a fixed time width.
- the first near-end signal and the second near-end signal of the digital signal are generated in step S505
- the first near-end signal is generated by the sixth near-end signal delay unit 1666 for a predetermined time.
- the delay is added, and the second near-end signal is subjected to adaptive filter processing by the first adaptive filter 163 (S506).
- the amount of delay added by the sixth near-end signal delay unit 166 it is appropriate to set the amount of delay added by the sixth near-end signal delay unit 166 to be equal to the coefficient length of the first adaptive filter 163.
- the tap length of the first adaptive filter 16 3 is set to about half of the tap length.
- the filtering processing is performed by a method of convolving the output signal of the second near-end voice converter 122 with the coefficient of the first filter.
- step S506 a delay is added to the first near-end signal, and the adaptive filter processing is performed on the second near-end signal, the signal after the delay addition and the signal after the adaptive filter processing are echo-formed.
- the difference signal between these signals is input to the minute signal output section 16 5 and the echo component signal output section 16 5 (S507).
- the difference calculated by the echo component signal output unit 165 is fed back to the first adaptive filter 163, and the second adaptive filter 163 controls the second adaptive filter 163 to minimize the absolute value of the difference signal.
- adaptive filter processing is performed on the near-end signal.
- the first near-end signal is added with a predetermined time delay by a seventh near-end signal delay unit 176, and is output from the echo component signal output unit 165.
- the delay amount added by the seventh near-end signal delay unit 176 is set to be equal to the coefficient length of the second adaptive filter 173. Specifically, it is preferable to set the length to about half the tap length of the second adaptive filter 173.
- the filter / lettering processing is performed by a method of convoluting the coefficient of the second filter with the output signal from the echo component signal output unit 165.
- step S508 a delay is added to the first near-end signal, and the output signal from the echo component signal output unit 165 is subjected to adaptive filter processing.
- the difference calculated by the third output unit 175 is fed back to the second adaptive filter 173, and the second adaptive filter 173 sets the echo component signal so as to minimize the absolute value of the difference signal.
- the output signal from the output section 165 is subjected to adaptive filter processing.
- step S509 The signal generated in step S509 is output to the far end as an echo suppression signal (S510).
- the first filter coefficient and the second filter coefficient are updated (S511).
- the update of the filter coefficient is performed when the adaptive control section 181 determines whether or not to update the filter coefficient of each of the adaptive filters 163 and 173 and determines that the update is to be performed.
- the adaptive control unit 18 1 determines that the near-end signal is superior to the far-end signal input from the far end, the adaptive control unit 18 1 reduces the output power of the echo component signal output unit 16 5 to the minimum.
- the output power of the third output unit 1 75 becomes minimum.
- the adaptive control unit 181 which updates the filter coefficients of the second adaptive filter 17 3, simply makes a decision that the power of the near-end signal exceeds a predetermined first threshold and the far-end If the correlation between the signal and the output signal of the second near-end voice converter 122 is high, it is determined that the far-end signal is dominant, and the power of the far-end signal is equal to the predetermined second power. If the threshold value is not exceeded and the power of the output signal of the second near-end speech converter 122 exceeds a predetermined third threshold value, it is preferable to determine that the near-end speaker speech is dominant. It is.
- the whitening between the far-end signal and the output signal of the second near-end audio converter 122 is described. The determination can be made based on whether or not the maximum value of the cross-correlation function is equal to or greater than a predetermined value.
- the adaptive control unit 18 1 determines that the power of the output signal of the second near-end voice conversion unit 122 exceeds a predetermined first threshold, and that the power of the far-end signal is a predetermined second threshold. If the signal exceeds the threshold, it is determined that the far-end signal is more dominant than the near-end signal, the power of the far-end signal does not exceed the third predetermined threshold, and the second near-end voice converter 1 2 2 If the power of the output signal exceeds a predetermined fourth threshold, it may be determined that the near-end signal is superior to the far-end signal. By performing control in this manner, the filter coefficients of the first adaptive filter 163 are updated when the near end speaker is dominant.
- the echo component signal output unit 165 converts the far-end signal by the far-end signal conversion unit 112 and outputs the far-end voice to the second near-end voice conversion unit 122.
- the signal corresponding to the embedded sound is included, the signal corresponding to the near-end speaker's voice will output a suppressed signal. Therefore, a signal having a strong echo component is output from the echo component signal output unit 165.
- the filter coefficients of the second adaptive filter 1 73 will be updated if the far-end signal is dominant.
- the output signal of the seventh near-end signal delay unit 176 includes the far-end voice output from the far-end signal conversion unit 112 in the second near-end signal.
- the echo wrapped around the voice conversion unit 122 and the near-end signal which is the signal of the near-end speaker voice are included, the echo component included in the input signal of the second adaptive filter 173 is canceled. Is done.
- the output of the third output unit 175 is output with the near-end speaker's voice emphasized. Will be done.
- a method of updating the filter coefficients of the first adaptive filter 163 and the second adaptive filter 173 a method based on known adaptive signal processing is appropriate. For example, a learning identification method, a FRLS method, or the like is used. Can be used.
- step S511 it is determined whether the voice call has ended based on the level of the near-end signal or the like (S512), and it is determined that the voice call has ended. In this case, the process proceeds to step S513, and if it is determined that the process has not been completed, the process returns to step S503 to repeat the above process.
- the processing in steps S503 and S504 may be omitted.
- step S512 the filter coefficient of the first adaptive filter 163 is stored in the first coefficient storage 164 in association with the opening angle detected by the current value detector 131. Then, the filter coefficient of the second adaptive filter 173 is stored in the second coefficient storage unit 174 in association with the opening angle detected by the current value detection unit 131, and the process returns to step S501. Repeat the above process.
- FIG. 24 is a diagram illustrating an example of an output waveform of an audio signal output from the far-end signal conversion unit 112 when an audio signal is included in the far-end signal.
- FIGS. 24 (a) to (c) show the case where the audio signal output from the far-end signal conversion unit 112 has no distortion, that is, the far-end signal is linearly converted to far-end audio.
- the example of the output waveform in the case is shown.
- FIG. 24 (a) is a diagram showing a signal waveform of a signal output to the far end when the echo suppression processing is not performed.
- the voice output from the far-end signal converter 112 is sent to the first near-end voice converter 121 and the second near-end voice converter 122. Therefore, as shown in Fig. 24 (a), the voice signal resulting from the wraparound voice is superimposed as an echo on the signal output to the far end.
- FIG. 24 (b) is a diagram showing a signal waveform of a signal output to the far end when an echo canceller based on a conventional learning identification method is used. It can be seen that the echo can be sufficiently suppressed even when the conventional echo canceller is used.
- FIG. 24 (c) is a diagram illustrating a signal waveform of a signal output to the far end when the communication device according to the third embodiment of the present invention is used. Call according to the third embodiment of the present invention It can be seen that the echo can be sufficiently suppressed even when the device is used.
- FIG. 24 (d) is a diagram showing a signal waveform of a signal output to the far end when the echo suppression processing is not performed. It can be seen that there is a large amplitude echo when the echo suppression processing is not performed.
- FIG. 24 (e) shows a signal waveform of a signal output to the far end when a conventional echo canceller is used. It can be seen that when the conventional echo canceller is used, some echoes can be suppressed, but unerased parts remain. Since the conventional echo canceller performs linear echo suppression processing, it is necessary to appropriately perform echo prediction for a non-linear system such as one in which the output signal of the far-end signal converter 112 has distortion. Cannot be done in principle. Since the estimated echo deviates from the true echo due to the non-linearity and remains without being suppressed, when the conventional echo canceller is used, the echo remains unerased.
- FIG. 24 (f) is a diagram showing a signal waveform of a signal output to the far end when the communication device according to the third embodiment of the present invention is used.
- the communication apparatus according to the third embodiment of the present invention it can be seen that although the echo has not been completely eliminated, the echo cancellation remains less than the conventional echo canceller.
- the communication apparatus provides an adaptive filter such that the first adaptive filter is configured to minimize the absolute value of the difference signal output from the echo component signal output unit.
- the first echo component corresponding to the current relative position between the far-end signal conversion unit and the near-end voice conversion unit is detected, and the second adaptive filter is included in the near-end signal. Since the second output component generates the second echo component and the third output portion removes the echo component, even if the current relative position between the far-end signal conversion unit and the near-end speech conversion unit is changed, Ko One suppression performance is maintained, and high-quality calls can be made.
- the first initial value determining unit and the second initial value determining unit determine the initial values of the first filter coefficient and the second filter coefficient according to the current value of the parameter detected by the current value detecting unit. Therefore, even if the current relative position between the far-end signal converter and the near-end voice converter is changed, echo suppression performance is maintained shortly after the call starts, and high-quality calls can be made. Further, the adaptive control unit instructs the first adaptive filter and the second adaptive filter to update the first filter coefficient and the second filter coefficient based on the far-end signal and the near-end signal. Therefore, even if the current relative position between the far-end signal converter and the near-end voice converter is changed, the echo suppression performance can be improved in a short time. Maintained and high quality calls can be made.
- the first near-end audio converter 1 2 1 is arranged at a position closer to the far-end signal converter than the second near-short audio converter 1 2 2.
- the present invention is not limited to this.
- the second near-short sound converter 122 may be arranged at a position closer to the far-end signal converter than the first near-end sound converter 122.
- the communication device according to the present invention can be applied to applications such as a communication device capable of performing high-quality communication without deteriorating echo suppression performance even when the relative position of a speaker and a microphone is changed.
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Telephone Function (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
- Circuit For Audible Band Transducer (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/545,587 US20060245583A1 (en) | 2003-07-17 | 2004-07-01 | Speech communication apparatus |
EP04747166A EP1655856A1 (en) | 2003-07-17 | 2004-07-01 | Speech communication apparatus |
Applications Claiming Priority (4)
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JP2003-276181 | 2003-07-17 | ||
JP2003276181 | 2003-07-17 | ||
JP2004-172528 | 2004-06-10 | ||
JP2004172528A JP2005051744A (ja) | 2003-07-17 | 2004-06-10 | 通話装置 |
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WO2005008910A1 true WO2005008910A1 (ja) | 2005-01-27 |
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PCT/JP2004/009697 WO2005008910A1 (ja) | 2003-07-17 | 2004-07-01 | 通話装置 |
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US (1) | US20060245583A1 (ja) |
EP (1) | EP1655856A1 (ja) |
JP (1) | JP2005051744A (ja) |
WO (1) | WO2005008910A1 (ja) |
Families Citing this family (12)
Publication number | Priority date | Publication date | Assignee | Title |
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US8380773B2 (en) * | 2005-02-18 | 2013-02-19 | Netlogic Microsystems, Inc. | System and method for adaptive nonlinear filtering |
WO2007049643A1 (ja) | 2005-10-26 | 2007-05-03 | Nec Corporation | エコー抑圧方法及び装置 |
JP5228407B2 (ja) * | 2007-09-04 | 2013-07-03 | ヤマハ株式会社 | 放収音装置 |
JP5034819B2 (ja) | 2007-09-21 | 2012-09-26 | ヤマハ株式会社 | 放収音装置 |
JP5293305B2 (ja) * | 2008-03-27 | 2013-09-18 | ヤマハ株式会社 | 音声処理装置 |
US9654609B2 (en) | 2011-12-16 | 2017-05-16 | Qualcomm Incorporated | Optimizing audio processing functions by dynamically compensating for variable distances between speaker(s) and microphone(s) in an accessory device |
US9300266B2 (en) * | 2013-02-12 | 2016-03-29 | Qualcomm Incorporated | Speaker equalization for mobile devices |
CN105991857A (zh) * | 2015-02-12 | 2016-10-05 | 中兴通讯股份有限公司 | 一种实现参考信号调整的方法及装置 |
US9894439B1 (en) * | 2017-01-31 | 2018-02-13 | Dell Products L.P. | Adaptive microphone signal processing for a foldable computing device |
US10200540B1 (en) * | 2017-08-03 | 2019-02-05 | Bose Corporation | Efficient reutilization of acoustic echo canceler channels |
CN111736797B (zh) * | 2020-05-21 | 2024-04-05 | 阿波罗智联(北京)科技有限公司 | 负延时时间的检测方法、装置、电子设备及存储介质 |
CN111883153B (zh) * | 2020-06-28 | 2024-02-23 | 厦门亿联网络技术股份有限公司 | 一种基于麦克风阵列的双端讲话状态检测方法及装置 |
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2004
- 2004-06-10 JP JP2004172528A patent/JP2005051744A/ja not_active Withdrawn
- 2004-07-01 WO PCT/JP2004/009697 patent/WO2005008910A1/ja not_active Application Discontinuation
- 2004-07-01 EP EP04747166A patent/EP1655856A1/en not_active Withdrawn
- 2004-07-01 US US10/545,587 patent/US20060245583A1/en not_active Abandoned
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US20060245583A1 (en) | 2006-11-02 |
EP1655856A1 (en) | 2006-05-10 |
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