JP5032959B2 - Acoustic input device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To emphasize and output sound from a sound source present in an object direction. <P>SOLUTION: A phase difference correction part 20 extracts discrete values of first and second observation signals generated by first and second directional microphones 10 and 11, and shifts only the phase difference in the case where a sound source is present in the object direction with respect to the discrete value of the second observation signal. A sound source direction determination part 21 calculates first and second observation power values being power values of the first and second observation signals. When at least one of the first and second observation power values is not larger than a threshold value, it is determined that the sound source is not present in the object direction and, when both the first and second observation power values are larger than the threshold value and a relative ratio of the first and second observation power values is smaller than another threshold value, it is determined that the sound source is present in the object direction. An output calculation part 22 outputs a synthesized signal of the first and second observation signals by amplifying it with a large amplification factor when the sound source is present in the object direction, and outputs the synthesized signal by amplifying it with a small amplification factor when the sound source is not present in the object direction. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an acoustic input device that emphasizes and outputs sound from a sound source that exists in a predetermined target direction.

  As an acoustic input device that collects sound from a sound source, for example, it is provided in a door phone sub unit of an interphone system, and the sound (sound) of a specific speaker (sound source) existing in front of the door phone sub unit is collected. There is something to do. In the acoustic input device provided in such a door phone sub unit, only the voice of the speaker is collected, and the sound other than the voice of the speaker (for example, reflected sound from the wall surface or ambient noise) is not collected. Therefore, it is necessary to predict in advance the direction in which the speaker exists (target direction) and to direct the directivity to the predicted target direction.

  As a conventional acoustic input device that collects sound from a sound source that exists in a target direction, there is one that collects sound using a single directional microphone. The directional microphone can collect sound from a sound source that exists in a sound collection region with a somewhat small directivity angle.

  As another example of a conventional acoustic input device that collects sound from a sound source, Patent Document 1 discloses a omnidirectional microphone that is a pressure microphone, a bidirectional microphone that is a speed microphone, and a non-directional microphone. A sound source direction determination apparatus is disclosed that includes a phase comparator that determines whether the phase of the waveform signal of the bidirectional microphone is advanced or delayed with respect to the waveform signal of the directional microphone.

  In the sound source direction determination apparatus of Patent Document 1, the waveform signal of the bidirectional microphone (speed microphone) is omnidirectional when the sound source is present on the front side of two microphones (omnidirectional microphone and bidirectional microphone). When the sound source is present on the back side of the two microphones, the phase is delayed by 90 degrees from the waveform signal of the omnidirectional microphone. When the phase comparator determines that the phase of the waveform signal of the bi-directional microphone is ahead of the waveform signal of the omnidirectional microphone, the phase comparator determines that the sound source is present on the front side, while the waveform signal of the omnidirectional microphone If it is determined that the sound source is slow, it is determined that the sound source exists on the back side.

From the above, according to the sound source direction determination device of Patent Document 1, it can be determined whether the sound source exists on the front side or the back side of the two microphones.
JP 2003-333680 A (paragraphs 0028 to 0048 and FIGS. 1 to 3)

  However, the conventional sound input device using a single microphone can collect and output sound from a sound source that exists within a certain range, but it is not sufficient from a practical point of view. There is a problem that noise and the like existing outside the target direction are emphasized and output in the same manner as the sound from the sound source existing in the target direction (for example, the voice of a specific speaker).

  As a conventional means for solving the above problem, it is conceivable to lengthen the acoustic tube of the microphone, but it is not practical. In addition, although signal processing such as noise removal may be performed, a new problem of excessive calculation amount occurs.

  Moreover, although the sound source direction determination device of Patent Document 1 can determine whether a sound source exists on the front side or the back side of two microphones, the sound source is detected from a sound source that exists in a specific target direction. The sound could not be output with emphasis.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an acoustic input device that can emphasize and output sound from a sound source existing in a target direction.

According to the first aspect of the present invention, each has a sound collection region having a predetermined directivity angle, receives a sound wave from a sound source existing in the sound collection region, generates an observation signal based on the received sound wave, A first directional microphone and a second directional microphone installed in close proximity so that parts of the sound region overlap each other including a predetermined target direction, and the first directional microphone to the first The observation signal is received, the second observation signal is received from the second directional microphone, the phase difference between the received first observation signal and the second observation signal is determined, and the sound source exists in the target direction. A phase difference correction unit that corrects only a phase difference between the first observation signal and the second observation signal, and the first observation signal and the second observation after correction by the phase difference correction unit. The sound source exists in the target direction using a signal A sound source direction determination unit that determines whether or not the sound source direction determination unit determines that the sound source is present in the target direction, and the first observation signal generated by the first directional microphone and the A synthesized signal of the first observation signal and the second observation signal after the phase difference from the second observation signal generated by the second directional microphone is corrected by the phase difference is a first signal. When the sound source direction determination unit determines that the sound source does not exist in the target direction, the synthesized signal is amplified with an amplification factor smaller than the first amplification factor. An output calculation unit that outputs the first observation signal after being corrected by the phase difference correction unit as a first observation power value, and after being corrected by the phase difference correction unit The power of the second observation signal Was the second observation power value, the sound source direction determination unit, none of the previous SL the second observation power value and the first observation power value is greater than a predetermined threshold value, and the first observation If the condition that the relative ratio between the power value and the second observed power value is less than a predetermined set value is satisfied, it is determined that the sound source exists in the target direction. If the condition is not satisfied, the sound source It is determined that the target direction does not exist.

The invention of claim 2 has a sound collection region having a predetermined directivity angle, receives a sound wave from a sound source existing in the sound collection region, generates an observation signal based on the received sound wave, A first directional microphone and a second directional microphone installed in close proximity so that parts of the sound region overlap each other including a predetermined target direction, and the first directional microphone to the first The observation signal is received, the second observation signal is received from the second directional microphone, the phase difference between the received first observation signal and the second observation signal is determined, and the sound source exists in the target direction. A phase difference correction unit that corrects only a phase difference between the first observation signal and the second observation signal, and the first observation signal and the second observation after correction by the phase difference correction unit. The sound source exists in the target direction using a signal A sound source direction determination unit that determines whether or not the sound source direction determination unit determines that the sound source is present in the target direction, and the first observation signal generated by the first directional microphone and the A synthesized signal of the first observation signal and the second observation signal after the phase difference from the second observation signal generated by the second directional microphone is corrected by the phase difference is a first signal. When the sound source direction determination unit determines that the sound source does not exist in the target direction, the synthesized signal is amplified with an amplification factor smaller than the first amplification factor. and an output calculation unit for outputting Te, the sound source direction determination unit includes a discrete value x2 of the first discrete value x1 and the second observation signal observed signal after being corrected by the phase difference correcting unit Use the phase represented by Equation 3 Seeking function _{R ij (i, j = 1,2} ), if satisfying the cross-correlation function _{R 12} is equal to or higher than a predetermined value set based on the autocorrelation function _{R 11} or autocorrelation function _{R 22,} While it is determined that the sound source exists in the destination direction, if the condition is not satisfied, it is determined that the sound source does not exist in the destination direction.

According to a third aspect of the present invention, each has a sound collection region of a predetermined directivity angle, receives a sound wave from a sound source existing in the sound collection region, generates an observation signal based on the received sound wave, A first directional microphone, a second directional microphone, and the first directional microphone and the first directional microphones, which are disposed close to each other so as to overlap each other including a predetermined target direction . An omnidirectional microphone installed at an intermediate position between the two directional microphones for receiving a sound wave from the sound source and generating a reference observation signal based on the received sound wave, and a first directional microphone from the first directional microphone An observation signal is received, a second observation signal is received from the second directional microphone, a phase difference between the received first observation signal and the second observation signal is present, and a sound source exists in the target direction. First observation of the case A phase difference correction unit that corrects only a phase difference between the signal and the second observation signal, and the first observation signal and the second observation signal that have been corrected by the phase difference correction unit, A sound source direction determining unit that determines whether or not a sound source exists in the target direction; and when the sound source direction determining unit determines that the sound source exists in the target direction, the sound source is generated by the first directional microphone. The first observation signal and the second observation signal after the phase difference between the first observation signal and the second observation signal generated by the second directional microphone is corrected by the phase difference. When the synthesized signal with the observation signal is amplified and output at the first amplification factor, and the sound source direction determining unit determines that the sound source does not exist in the target direction, the synthesized signal is converted into the first signal. Amplify with an amplification factor smaller than the amplification factor. And an output calculation unit for outputting the phase difference correcting unit, the reference further receives the observation signals, the phase difference between the first observation signal thus received a reference observation signal the received, to the intended direction only the phase difference between the reference observation signal and the first observation signal when the sound source is present and correct, the power value first observation power value of the first observation signal after being corrected by the phase difference correcting unit The power value of the second observation signal after correction by the phase difference correction unit is set as a second observation power value, and the power value of the reference observation signal after correction by the phase difference correction unit is a reference observation power value, the sound source direction determination unit is included in the first range of relative ratio before Symbol first observation power value is set in advance for the previous Kimoto quasi observed power value and the reference observation the relative ratio before Symbol second observation power value for power values Determines that the sound source exists in the target direction when the condition is included in the preset second range, and determines that the sound source does not exist in the target direction when the condition is not satisfied. It is characterized by that.

The invention of claim 4 has a sound collection region having a predetermined directivity angle, receives a sound wave from a sound source existing in the sound collection region, generates an observation signal based on the received sound wave, A first directional microphone, a second directional microphone, and the first directional microphone and the first directional microphones, which are disposed close to each other so as to overlap each other including a predetermined target direction . An omnidirectional microphone installed at an intermediate position between the two directional microphones for receiving a sound wave from the sound source and generating a reference observation signal based on the received sound wave, and a first directional microphone from the first directional microphone An observation signal is received, a second observation signal is received from the second directional microphone, a phase difference between the received first observation signal and the second observation signal is present, and a sound source exists in the target direction. First observation of the case A phase difference correction unit that corrects only a phase difference between the signal and the second observation signal, and the first observation signal and the second observation signal that have been corrected by the phase difference correction unit, A sound source direction determining unit that determines whether or not a sound source exists in the target direction; and when the sound source direction determining unit determines that the sound source exists in the target direction, the sound source is generated by the first directional microphone. The first observation signal and the second observation signal after the phase difference between the first observation signal and the second observation signal generated by the second directional microphone is corrected by the phase difference. When the synthesized signal with the observation signal is amplified and output at the first amplification factor, and the sound source direction determining unit determines that the sound source does not exist in the target direction, the synthesized signal is converted into the first signal. Amplify with an amplification factor smaller than the amplification factor. And an output calculation unit for outputting the phase difference correcting unit includes a first discrete value of the observed signal is extracted at predetermined time intervals, the second observation signal of discrete values the predetermined said received said it received extracted with time intervals, the discrete values of the further received the reference observation signal the reference observation signal is extracted at the predetermined time interval, the discrete value of the first observation signal the extraction and the second observation signal a phase difference, the only phase difference between the first observation signal and the second observation signal when target direction to the sound source is present and correct, discrete values of the reference observation signal the extraction and the first observation signal the phase difference is corrected by a phase difference between the reference observation signal and the first observation signal when the sound source is present in the target direction, the sound source direction determination unit, said after being corrected by the phase difference correcting unit The discrete value x1 of the first observation signal is compensated by the phase difference correction unit. Correlation function represented by the number 4 using discrete values x0 of the reference observation signal after being corrected in discrete value x2 and the phase difference correction unit of the second observation signal after Tadashisa R _{ij (i,} j = 0, 1, 2) and determined, is included in the first range of relative ratio of the cross-correlation function _{R 01} for the autocorrelation function _{R 00} is preset cross-correlation function _{R 02} for said autocorrelation function _{R 00} If the relative ratio satisfies the condition included in the preset second range, it is determined that the sound source exists in the target direction, and if the condition is not satisfied, the sound source does not exist in the target direction. It is characterized by determining.

The invention of claim 5 has a sound collection region having a predetermined directivity angle, receives sound waves from a sound source existing in the sound collection region, generates an observation signal based on the received sound waves, A first directional microphone and a second directional microphone installed in close proximity so that parts of the sound region overlap each other including a predetermined target direction, and the first directional microphone to the first The observation signal is received, the second observation signal is received from the second directional microphone, the phase difference between the received first observation signal and the second observation signal is determined, and the sound source exists in the target direction. A phase difference correction unit that corrects only a phase difference between the first observation signal and the second observation signal, and the first observation signal and the second observation after correction by the phase difference correction unit. The sound source exists in the target direction using a signal A sound source direction determination unit that determines whether or not the sound source direction determination unit determines that the sound source is present in the target direction, and the first observation signal generated by the first directional microphone and the A synthesized signal of the first observation signal and the second observation signal after the phase difference from the second observation signal generated by the second directional microphone is corrected by the phase difference is a first signal. When the sound source direction determination unit determines that the sound source does not exist in the target direction, the synthesized signal is amplified with an amplification factor smaller than the first amplification factor. The sound source direction determining unit determines whether the sound source exists in the vicinity of the target direction when it is determined that the sound source does not exist in the target direction, The output calculation unit is When the sound source direction determination unit determines that the sound source is present in the vicinity of the target direction, the composite signal has a gain of a continuous change characteristic that monotonously decreases from the first gain as the distance from the target direction increases. Is amplified and output.

The invention of claim 6 has a sound collection region having a predetermined directivity angle, receives a sound wave from a sound source existing in the sound collection region, generates an observation signal based on the received sound wave, A first directional microphone, a second directional microphone, and the first directional microphone and the first directional microphones, which are disposed close to each other so as to overlap each other including a predetermined target direction . An omnidirectional microphone installed at an intermediate position between the two directional microphones for receiving a sound wave from the sound source and generating a reference observation signal based on the received sound wave, and a first directional microphone from the first directional microphone An observation signal is received, a second observation signal is received from the second directional microphone, a phase difference between the received first observation signal and the second observation signal is present, and a sound source exists in the target direction. First observation of the case A phase difference correction unit that corrects only a phase difference between the signal and the second observation signal, and the first observation signal and the second observation signal that have been corrected by the phase difference correction unit, A sound source direction determining unit that determines whether or not a sound source exists in the target direction; and when the sound source direction determining unit determines that the sound source exists in the target direction, the sound source is generated by the first directional microphone. The first observation signal and the second observation signal after the phase difference between the first observation signal and the second observation signal generated by the second directional microphone is corrected by the phase difference. When the synthesized signal with the observation signal is amplified and output at the first amplification factor, and the sound source direction determining unit determines that the sound source does not exist in the target direction, the synthesized signal is converted into the first signal. Amplify with an amplification factor smaller than the amplification factor. And an output calculation unit for outputting the phase difference correcting unit, the reference further receives the observation signals, the phase difference between the first observation signal thus received a reference observation signal the received, to the intended direction only the phase difference between the reference observation signal and the first observation signal when the sound source is present and correct, the power value first observation power value of the first observation signal after being corrected by the phase difference correcting unit The power value of the second observation signal after being corrected by the phase difference correction unit is set as the second observation power value, and the power value of the reference observation signal after being corrected by the phase difference correction unit was a reference observation power value, the sound source direction determination unit, none of the previous SL the second observation power value and the first observation power value is greater than a predetermined threshold value, and the first observation power value and the relative proportions of the second observation power value is predetermined 1 When the cross-correlation function between the first observation signal and the second observation signal is equal to or greater than the set value of the first observation signal , the autocorrelation function of the first observation signal or the autocorrelation function of the second observation signal When a condition that is equal to or greater than a predetermined second set value that is obtained is satisfied, the sound source is determined to be present in each of the target direction and other regions other than the target direction, while when the condition is not satisfied, sound source is determined not to exist in the target direction, the sound source is the target direction and when it is determined to exist in each of the other regions, the first observation power value relative to the previous Kimoto quasi observed power value is included in the range ratio preset, and when the relative ratio of the second observation power value for the reference observation power value is not included in the range, the first directional out of the other region Wherein determining that the sound source is present in the sound collecting area of Ikurohon, relative ratio of the second observation power value for the reference observation power value included in the range and the first observation with respect to the reference observation power value When the relative ratio of the power values is not included in the range, it is determined that the sound source exists in the sound collection region of the second directional microphone among the other regions .

According to a seventh aspect of the present invention, in the sixth aspect of the invention, the output calculation unit is configured such that the sound source direction determination unit includes the sound collection region of the first directional microphone or the second directivity among the other regions . When it is determined that the sound source exists in any of the sound collection areas of the microphone, the observation signal of the directional microphone in which the sound source does not exist in the sound collection area is amplified by the first amplification factor and output. Features.

The invention of claim 8 is the invention of claim 6 , further comprising driving means for tilting a directional axis of the first directional microphone or the second directional microphone, and the sound source direction determination unit is configured such that the sound source is If it is present in the target direction and further determined to be present in either one of the sound collection region of the first directional microphone and the sound collection region of the second directional microphone among the other regions, first relative ratio of the observed power value and the second observation power value and controls the driving means until the condition is less than the first set value, the output calculation unit, after the driving of said driving means If the sound source to the sound collecting area of the first sound collecting areas of the directional microphone or the second directional microphone by the sound source direction determination unit is determined to exist, put after driving of said driving means While outputting the combined signal and the second observation signal and the first observation signal is amplified by the first amplification factor, it determines that the sound by the sound source direction determination unit is not present in the intended direction When the driving means is driven, the combined signal of the first observation signal and the second observation signal is amplified with a second amplification factor smaller than the first amplification factor and output. Features.

The invention of claim 9 has a sound collection region having a predetermined directivity angle, receives sound waves from a sound source existing in the sound collection region, generates an observation signal based on the received sound waves, A first directional microphone, a second directional microphone, and the first directional microphone and the first directional microphones, which are disposed close to each other so as to overlap each other including a predetermined target direction . An omnidirectional microphone installed at an intermediate position between the two directional microphones for receiving a sound wave from the sound source and generating a reference observation signal based on the received sound wave, and a first directional microphone from the first directional microphone An observation signal is received, a second observation signal is received from the second directional microphone, a phase difference between the received first observation signal and the second observation signal is present, and a sound source exists in the target direction. First observation of the case A phase difference correction unit that corrects only a phase difference between the signal and the second observation signal, and the first observation signal and the second observation signal that have been corrected by the phase difference correction unit, A sound source direction determining unit that determines whether or not a sound source exists in the target direction; and when the sound source direction determining unit determines that the sound source exists in the target direction, the sound source is generated by the first directional microphone. The first observation signal and the second observation signal after the phase difference between the first observation signal and the second observation signal generated by the second directional microphone is corrected by the phase difference. When the synthesized signal with the observation signal is amplified and output at the first amplification factor, and the sound source direction determining unit determines that the sound source does not exist in the target direction, the synthesized signal is converted into the first signal. Amplify with an amplification factor smaller than the amplification factor. And an output calculation unit for outputting the phase difference correcting unit, the reference further receives the observation signals, the phase difference between the first observation signal thus received a reference observation signal the received, to the intended direction only the phase difference between the reference observation signal and the first observation signal when the sound source is present and correct, the power value first observation power value of the first observation signal after being corrected by the phase difference correcting unit The power value of the second observation signal after correction by the phase difference correction unit is set as a second observation power value, and the power value of the reference observation signal after correction by the phase difference correction unit is a reference observation power value, the sound source direction determination unit, when both are greater than a predetermined threshold and before Symbol the second observation power value and the first observation power value, the said first observation signal The cross-correlation function with the second observation signal is the first correlation signal. Each of the regions other than the target direction and the target direction when the condition is equal to or greater than a predetermined set value obtained from the autocorrelation function of the observed signal or the autocorrelation function of the second observed signal while determined to exist, when not satisfied the condition, the sound source is determined not to exist in the target direction, if the sound source is determined to be present in each of the target direction and the other region, before Symbol when the relative ratio of the relative standards observed power value first observation power value, and respective relative ratios of the second observation power value for the reference observation power value is included in a predetermined range, said first It is determined that the sound source exists in each of the sound collection regions of the directional microphone and the second directional microphone.

The invention of claim 10 is the invention of claim 9 , further comprising driving means for tilting the directional axes of the first directional microphone and the second directional microphone, and the sound source direction determining unit is configured such that the sound source is If it is determined that the signal exists in the target direction and further exists in both the sound collection region of the first directional microphone and the sound collection region of the second directional microphone among the other regions, the other When the two sound sources in the region are separated from the target direction by a half or more of the maximum value of the directivity angle of the first directional microphone and the second directional microphone, the first observation power controls the said drive means relative ratio of the value second observation power value until the condition is below a predetermined setting value, the output calculation unit, the sound source direction determination unit after the driving of said driving means Therefore if the sound source to the sound collecting area and the sound collection region of the second directional microphone of the first directional microphone is determined to exist, the said first observation signal after the driving of said driving means while that amplifies and outputs a combined signal of the second observation signal in the first amplification factor, when the sound source by the sound source direction determination unit determines that there is no said target direction, said driving means A combined signal of the first observation signal and the second observation signal after driving is amplified with a second amplification factor smaller than the first amplification factor and output.

  According to the first aspect of the present invention, the observation signals from the two microphones are used to determine whether or not the sound source exists in the target direction, and the amplification factor when the sound source exists in the target direction (first amplification) By making the rate higher than the amplification factor when the sound source does not exist in the target direction, it is possible to emphasize and output the sound from the sound source existing in the target direction.

Further, according to the invention of claim 1, by evaluating the relative ratio of the first observation power value and the second observation power value, the sound source is determined with high accuracy whether or not present in the target direction Can do.

According to the invention of claim 2, it is determined whether or not the sound source exists in the target direction using the observation signals from the two microphones, and the amplification factor (first amplification) when the sound source exists in the target direction. By making the rate higher than the amplification factor when the sound source does not exist in the target direction, it is possible to emphasize and output the sound from the sound source existing in the target direction.
Further, according to the invention of claim 2, by evaluating the cross-correlation function of the discrete values of the discrete values of the first observation signal and the second observation signal, whether the sound source is present in the target direction It can be determined with high accuracy.

According to the invention of claim 3, it is determined whether or not the sound source exists in the target direction using the observation signals from the two microphones, and the amplification factor (first amplification) when the sound source exists in the target direction. By making the rate higher than the amplification factor when the sound source does not exist in the target direction, it is possible to emphasize and output the sound from the sound source existing in the target direction.
Further, according to the invention of claim 3, by placing an omnidirectional microphone to an intermediate position of the first directional microphone and the second directional microphones, the relative reference observation power value of the non-directional microphone 1 , 2 can be used to accurately determine whether the sound source exists in the target direction.

According to the invention of claim 4, it is determined whether or not the sound source exists in the target direction using the observation signals from the two microphones, and the amplification factor (first amplification) when the sound source exists in the target direction. By making the rate higher than the amplification factor when the sound source does not exist in the target direction, it is possible to emphasize and output the sound from the sound source existing in the target direction.
Further, according to the invention of claim 4, by using the cross-correlation function between the autocorrelation function and the reference observation signals in the first and second observation signal of the reference observation signal, high to reduce the effects of uncorrelated noise The S / N ratio can be set, and the determination accuracy of whether or not the sound source exists in the target direction can be improved.

According to the fifth aspect of the present invention, it is determined whether or not the sound source exists in the target direction using the observation signals from the two microphones, and the amplification factor (first amplification) when the sound source exists in the target direction. By making the rate higher than the amplification factor when the sound source does not exist in the target direction, it is possible to emphasize and output the sound from the sound source existing in the target direction.
Further , according to the invention of claim 5 , it is possible to prevent the amplification factor for amplifying the synthesized signal from becoming discontinuous depending on the direction in which the sound source exists, and as a result, the output signal is always a continuous value. Can do.

According to the sixth aspect of the present invention, it is determined whether or not the sound source exists in the target direction using the observation signals from the two microphones, and the amplification factor (first amplification) when the sound source exists in the target direction. By making the rate higher than the amplification factor when the sound source does not exist in the target direction, it is possible to emphasize and output the sound from the sound source existing in the target direction.
Further, according to the invention of claim 6, the first directional microphone and one sound source in the sound collecting areas overlap area of the second directional microphones exist, the first directional microphone and the second directional It can be determined that another sound source exists only in one of the sound collection regions of the directional microphone.

According to the invention of claim 7 , it is possible to amplify and output the signal from the sound source in the target direction.

According to the invention of claim 8 , the signal from the sound source in the target direction can be amplified and output.

According to the invention of claim 9, it is determined whether or not the sound source exists in the target direction by using the observation signals from the two microphones, and the amplification factor (first amplification) when the sound source exists in the target direction. By making the rate higher than the amplification factor when the sound source does not exist in the target direction, it is possible to emphasize and output the sound from the sound source existing in the target direction.
Further, according to the invention of claim 9, the first directional microphone and one sound source in the sound collecting areas overlap area of the second directional microphones exist, the first directional microphone and the second directional It can be determined that another sound source exists only in one of the sound collection regions of the directional microphone.

According to the invention of claim 10 , it is possible to emphasize and output the signal from the sound source in the target direction.

(Embodiment 1)
First, the structure of the acoustic input device of Embodiment 1 is demonstrated using FIGS. As shown in FIG. 1, the acoustic input device includes a sound collecting unit 1 that collects sound from a sound source (not shown), and an observation signal x1 (t that will be described later based on the sound collected by the sound collecting unit 1 ), X2 (t), and a signal processing unit 2 that calculates an output signal y (k, m).

  The sound collection unit 1 includes a first directional microphone 10 and a second directional microphone 11 each having a sound collection region with predetermined directivity angles α1 and α2. As shown in FIG. 2B, the first directional microphone 10 and the second directional microphone 11 are configured such that a part of each sound collection area is in a specific target direction (the first directional microphone 10 in FIG. 2B). The directional microphone 10 and the second directional microphone 11 are disposed close to each other so as to overlap each other.

  As shown in FIG. 1, each of the first and second microphones 10 and 11 installed as described above receives a sound wave from a sound source, and an observation signal x1 (which is an electric signal based on the received sound wave). t), x2 (t). The first observation signal x1 (t) is output from the first directional microphone 10 to the signal processing unit 2, and the second observation signal x2 (t) is output from the second directional microphone 11 to the signal processing unit 2. .

  Incidentally, as shown in FIG. 3, the characteristics of the first and second directional microphones 10 and 11 are the first and second observed power values Px1 (k) described later at the position of the angle φ from the central axis A1 of the directivity. ), Px2 (k) is high and almost constant when 0 ° ≦ | φ | <φ1, decreases rapidly as the angle φ increases when φ1 ≦ | φ | <φ2, and decreases when φ2 <| φ | It is constant. In FIG. 2B, the angle θ of the region where the sound collection regions overlap is 0 ° <θ <min (α1, α2). In addition, the angle which becomes a half value of the sensitivity of φ = 0 ° is defined as a directivity angle α1 (α2).

  Although the first directional microphone 10 and the second directional microphone 11 of the present embodiment have the same sensitivity, even if the sensitivities are different, the observation signal based on the received sound wave is used. What is corrected with the sensitivity coefficient may be the new observation signals x1 (t) and x2 (t). Specifically, when the sensitivity coefficient of the first directional microphone 10 is m1 and the sensitivity coefficient of the second directional microphone 11 is m2 (m1 ≠ m2), (the first directional microphone 10 receives the wave) (Observation signal xm1) based on the sound wave received by the second directional microphone 11 is defined as the first observation signal x1 (t) transmitted to the signal processing unit 2 May be the second observation signal x2 (t) transmitted to the signal processing unit 2. At this time, the sensitivity coefficients m1 and m2 are set to satisfy m1: m2 = √ (Px2): √ (Px1) using Px1 and Px2 described later. The same applies to the following description.

  The signal processing unit 2 shown in FIG. 1 receives the first and second observation signals x1 (t) and x2 (t) and receives the discrete value x1 (k, m) of the first observation signal and the second observation signal. Phase difference correction unit 20 for correcting the phase difference of discrete values x2 (k, m) of the first and second values based on discrete values x1 (k, m) and x2 (k, m) of the first and second observation signals. The sound source direction determination unit 21 that determines whether or not the sound source exists in the target direction using the observed power values Px1 (k) and Px2 (k) of 2, and the output signal according to the determination result of the sound source direction determination unit 21 and an output calculation unit 22 that outputs y (k, m).

  The phase difference correction unit 20 receives the first observation signal x1 (t) from the first directional microphone 10, and receives the received first observation signal x1 (t) as shown in FIG. 5B. The frame is divided into frames having a frame length L, and a discrete value x1 (k, m) of the first observation signal is extracted at each predetermined time interval Δt for each frame. Similarly, the second observation signal x2 (t) is received from the second directional microphone 11, and the second observation signal x2 (t) is divided into frames having the frame length L, and the second observation signal x2 (t) is divided into frames for each frame. A discrete value x2 (k, m) of the observed signal is extracted at a predetermined time interval Δt. The discrete values x1 (k, m) and x2 (k, m) of the first and second observation signals are the mth discrete values in the kth frame.

  The phase difference correction unit 20 that has extracted the discrete values x1 (k, m) and x2 (k, m) of the first and second observation signals and the extracted discrete value x1 (k, m) of the first observation signal. The phase difference between the discrete values x2 (k, m) of the second observation signal is the phase difference between the first observation signal x1 (t) and the second observation signal x2 (t) when a sound source is present in the target direction. Only correct.

  For example, when the target direction is a direction B inclined by an angle φ from the central axis A of the first directional microphone 10 and the second directional microphone 11 as shown in FIG. As shown in FIG. 2, when the sound source S exists in the target direction, the first directional microphone 10 and the second directional microphone 11 are installed close to each other, so that the sound waves from the sound source S are incident substantially in parallel. To do. Therefore, a phase difference 2dsinφ (2d: distance between the first directional microphone 10 and the second directional microphone 11) is generated between the first observation signal x1 (t) and the second observation signal x2 (t). . If the speed of sound is c, a time lag occurs by the time τ = 2dsinφ / c (see FIG. 5A). From the above, as shown in FIG. 5B, the discrete value x2 (k, m) of the second observation signal is delayed by the time τ, and the new discrete value x2 ′ (k, m, By setting m) = x2 (k, m−τ / Δt), the phase difference between the discrete value x1 (k, m) of the first observation signal and the discrete value x2 (k, m) of the second observation signal Can be corrected.

  In the present embodiment, as shown in FIG. 2B, since the target direction is the direction of the central axis A of the first directional microphone 10 and the second directional microphone 11, the sound source is directed to the target direction. Since there is no phase difference between the first observation signal x1 (t) and the second observation signal x2 (t) in the presence of S1, x2 ′ (k, m) = x2 (k, m). .

  Discrete values x1 (k, m) and x2 '(k, m) of the first and second observation signals corrected by the phase difference correction unit 20 are output to the sound source direction determination unit 21.

  The sound source direction determination unit 21 shown in FIG. 1 calculates an average value for a predetermined time (frame length) of the sum of squares of the discrete value x1 (k, m) of the first observed signal for each frame as shown in Equation 5. The first observed power value Px1 (k) is calculated, and the average value of the second sum of squares of the discrete value x2 ′ (k, m) of the second observed signal is calculated for each frame to obtain the second The observed power value is Px2 (k). In Equation 5, i = 1 and 2.

  The sound source direction determination unit 21 that has calculated the first and second observed power values Px1 (k) and Px2 (k) uses the first and second observed power values Px1 (k) and Px2 (k) to determine whether the sound source is It is determined whether or not it exists in the target direction.

  Here, as shown in FIG. 2B, in a region where the sound collection region of the first directional microphone 10 and the sound collection region of the second directional microphone 11 overlap (φ1 in FIG. 2B), The relative ratio between the first observed power value Px1 (k) and the second observed power value Px2 (k) is small, and the first observed power value Px1 in a region other than the above (for example, φ2 in FIG. 2B). The relative ratio between (k) and the second observed power value Px2 (k) increases.

Therefore, the sound source direction determination unit 21 shown in FIG. 1 has both the first and second observation power values Px1 (k) and Px2 (k) larger than the predetermined threshold value Pth, and the first observation power value Px1 (k ) And the second observed power value Px2 (k) | 10log ₁₀ (Px1 (k) / Px2 (k)) | (dB) is 0 or more and less than the predetermined set value ε (dB) (0 ≦ | 10log) _{When the condition of 10} (Px1 (k) / Px2 (k)) | <ε) is satisfied, it is determined that the sound source exists in the target direction. On the other hand, when the above condition is not satisfied, the sound source direction determination unit 21 determines that the sound source does not exist in the target direction.

  The output calculation unit 22 receives the first observation signal x1 (t) from the first directional microphone 10 and the second observation signal x2 (t) from the second directional microphone 11, and outputs a digital signal processor ( (Hereinafter referred to as “DSP”), the discrete values x1 (k, m) and x2 (k, m) of the first and second observation signals from the first and second observation signals x1 (t) and x2 (t). ), The discrete value x2 (k, m) of the second observation signal is delayed by time τ, and the new discrete value x2 ′ (k, m) = x2 (k, m− τ / Δt), and the sum (x1 (k, m) + x2 ′ (k, m)) of the discrete values x1 (k, m) and x2 ′ (k, m) of the first and second observation signals is obtained. In this embodiment, since no delay occurs, x2 ′ (k, m) = x2 (k, m).

  When the sound source direction determination unit 21 determines that the sound source exists in the target direction, the output calculation unit 22 has a discrete value x1 (k, m) of the first observation signal and a discrete value x2 ′ of the second observation signal. A composite signal (x1 (k, m) + x2 ′ (k, m)) of (k, m) is amplified with a first amplification factor G1 and output as an output signal y (k, m) of a digital output signal. On the other hand, when the sound source direction determination unit 21 determines that the sound source does not exist in the target direction, the output calculation unit 22 performs the first amplification on the combined signal (x1 (k, m) + x2 ′ (k, m)). Amplification is performed at a second amplification factor G2 smaller than the factor G1, and the result is output as an output signal y (k, m).

  Next, the operation of the acoustic input device of this embodiment will be described with reference to FIG. First, when the first and second microphones 10 and 11 of the sound collection unit 1 receive a sound wave from a sound source, the first and second observation signals x1 (t) and x2 (t) are signal-processed from the sound collection unit 1. Transmitted to part 2. In the signal processing unit 2, the phase difference correction unit 20 extracts the discrete values x1 (k, m) and x2 (k, m) of the first and second observation signals (S1, S2). Thereafter, the phase difference correction unit 20 shifts the phase difference of the second observation signal by the phase difference when the sound source exists in the target direction with respect to the discrete value x2 (k, m) of the second observation signal. A discrete value x2 ′ (k, m) is set (S3).

The sound source direction determination unit 21 calculates the first and second observation power values Px1 (k) and Px2 (k) for each frame (S4, S5). Thereafter, the sound source direction determination unit 21 examines whether or not the condition that both the first and second observation power values Px1 (k) and Px2 (k) are larger than the threshold value Pth is satisfied (S6). If the above condition is not satisfied, it is determined that the sound source is present in the direction other than the target direction (outside the sound collection area) (S9). On the other hand, when the above condition is satisfied, the sound source direction determination unit 21 examines whether or not the condition that the relative ratio | 10log ₁₀ (Px1 (k) / Px2 (k)) | is less than the threshold ε is satisfied (S7). If the above condition is satisfied, it is determined that the sound source exists in the target direction (in the sound collection area) (S8). If the above condition is not satisfied, it is determined that the sound source exists in a direction other than the target direction (S9).

  When it is determined that the sound source exists in the target direction, the output calculation unit 22 outputs G1 (x1 (k, m) + x2 ′ (k, m)) as the output signal y (k, m) (S10), When it is determined that the sound source does not exist in the target direction, G2 (x1 (k, m) + x2 ′ (k, m)) is amplified and output as the output signal y (k, m) (S11).

  As described above, according to the present embodiment, the observation signals (first observation signal x1 (k, m), second observation) from the two microphones (first directional microphone 10 and second directional microphone 11). Signal x2 (k, m)) is used to determine whether the sound source exists in the target direction, and the amplification factor (first amplification factor G1) when the sound source exists in the target direction By making it larger than the amplification factor (second amplification factor G2) when it does not exist in the direction, the sound from the sound source existing in the target direction can be emphasized and output.

Further, by evaluating the relative ratio | 10log ₁₀ (Px1 (k) / Px2 (k)) | between the first observed power value Px1 (k) and the second observed power value Px2 (k), the sound source It can be accurately determined whether or not it exists in the direction.

  Furthermore, by setting the two microphones 10 and 11 so that the sound collecting areas partially overlap each other, sharper directivity can be obtained as compared with a single directional microphone.

  In addition, the directivity angles α1 and α2 of the first and second directional microphones 10 and 11 of the first embodiment may have various directivity angles. Specifically, it is not limited to the one shown in FIG. 2, but as shown in FIG. 7 (with a directivity angle of 90 °) or as shown in FIG. 8 (with a directivity angle of 180 °). But you can. The same applies to the following embodiments.

  As a modification of the first embodiment, the output calculation unit 22 illustrated in FIG. 1 does not output the digital signal output signal y (k, m), but the first observation signal x1 (t) 2 (x1 (t) + x2 ′ (t)) is amplified with a new second observation signal x2 ′ (t) = x2 (t−τ) obtained by delaying the second observation signal x2 (t) by time τ. May be output. That is, when it is determined that the sound source exists in the target direction, the output calculation unit 22 outputs the output signal y (t) = G1 (x1 (t) + x2 ′ (t)), and the sound source exists in the target direction. When it is determined not to output, the output signal y (t) = G2 (x1 (t) + x2 ′ (t)) (G2 <G1) is output. The same applies to the following embodiments.

(Embodiment 2)
In the acoustic input device according to the second embodiment, the sound source direction determination unit 21 illustrated in FIG. 1 has the cross-correlation function R ₁₂ of the discrete values x1 (k, m) and x2 ′ (k, m) of the first and second observation signals. The difference from the sound input device of the first embodiment is that (Equation 6) is calculated for each frame. The correlation function R _{ij in Equation} 6 is an autocorrelation function when i = j, and a cross-correlation function when i ≠ j. In addition, about the component similar to Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

As shown in FIG. 9, the cross-correlation function R ₁₂ is large in an area where the sound collection areas of the first directional microphone 10 and the second directional microphone 11 overlap (−θ / 2 <φ <θ / 2). It takes a value and becomes a small value in other areas than the above. Therefore, the sound source direction determination unit 21 determines that the sound source exists in the target direction when the condition that the cross-correlation function R ₁₂ > threshold Rth is satisfied, and determines that the sound source does not exist in the target direction when the above condition is not satisfied. judge.

The determination of the threshold value Rth, the discrete values x1 (k, m) of the first observation signal discrete value x2 (k, m) of the autocorrelation function _{R 11} or the second observation signal of the autocorrelation function _{R 22} of Used. Since the autocorrelation functions R ₁₁ and R ₂₂ are large values regardless of the direction in which the sound source exists, Rth = ζR _ii (i = 1, 2) and 0 <ζ <1 are determined.

As described above, according to this embodiment, the discrete values x1 (k, m) of the first observation signal discrete value x2 '(k, m) of the second observation signal by evaluating the cross-correlation function R ₁₂ in It is possible to accurately determine whether or not the sound source exists in the target direction.

(Embodiment 3)
As shown in FIG. 10A, the acoustic input device according to the third embodiment is installed in the sound collection unit 1a at an intermediate position between the first directional microphone 10 and the second directional microphone 11, and the sound wave from the sound source. Is different from the acoustic input device of the first embodiment (see FIG. 1) in that it includes a non-directional microphone 12 that generates a reference observation signal that is an electric signal based on the received sound wave. In addition, about the component similar to Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The omnidirectional microphone 12 of the present embodiment uses the one having the same sensitivity as that of the first and second directional microphones 10 and 11, but it is based on the received sound wave even if the sensitivity is different. The observation signal corrected with the sensitivity coefficient may be used as a new observation signal x0 (t). Specifically, when the sensitivity coefficient of the omnidirectional microphone 12 is m0, (the observation signal based on the sound wave received by the omnidirectional microphone 12 × m0) is the reference observation signal transmitted to the signal processing unit 2a. x0 (t) may be used. At this time, the sensitivity coefficient m0 is set to satisfy m0: m1 = √ (Px1): √ (Px0) using Px0 described later. The same applies to the following description.

  In the signal processing unit 2a of the present embodiment, as shown in FIG. 11, the phase difference correction unit 20a receives the reference observation signal x0 (t) from the omnidirectional microphone 12, and receives the received reference observation signal x0 (t). Discrete values x0 (k, m) are extracted at a predetermined time interval Δt, and the discrete reference values x0 (k, m) of the extracted reference observation signals are used as reference observation signals x0 (t) when a sound source exists in the target direction. And the first observation signal x1 (t) are shifted by the phase difference.

  In addition, the sound source direction determination unit 21a calculates an average value in a predetermined time (frame length L) of the square sum of the discrete values x0 (k, m) of the reference observation signal shifted by the phase difference correction unit 20a to perform the reference observation. The power value is Px0 (k). If the distance from the omnidirectional microphone 12 to the sound source is constant, the reference observation power value Px0 (k) is constant regardless of the direction of the sound source.

  The sound source direction determination unit 21a that has calculated the reference observation power value Px0 (k) has a relative ratio (Px1 (k) / Px0 (k) of the first observation power value Px1 (k) to the reference observation power value Px0 (k). ) Is included in the preset first range, and the relative ratio (Px2 (k) / Px0 (k)) of the second observed power value Px2 (k) to the reference observed power value Px0 (k) is preset. If the condition included in the second range is satisfied, it is determined that the sound source exists in the target direction. On the other hand, when the above condition is not satisfied, the sound source direction determination unit 21a determines that the sound source does not exist in the target direction.

  Here, the first range of the present embodiment is a range greater than the initially set threshold value δ and 1 or less (δ <Px1 (k) / Px0 (k) ≦ 1). The second range of the present embodiment is also a range greater than the initially set threshold value δ and 1 or less (δ <Px2 (k) / Px0 (k) ≦ 1).

  As described above, according to the present embodiment, the reference observation power value Px0 of the omnidirectional microphone 12 is provided by installing the omnidirectional microphone 12 at an intermediate position between the first directional microphone 10 and the second directional microphone 11. By using the first and second observed power values Px1 (k) and Px2 (k) for (k), it can be accurately determined whether or not the sound source exists in the target direction.

(Embodiment 4)
In the acoustic input device according to the fourth embodiment, the sound source direction determination unit 21a illustrated in FIG. 11 includes the first and second observation signals x1 (k, m), x2 (k, m) and the reference observation signal x0 (k, m). Is used to determine the correlation function R _ij (i, j = 0,1,2,2) expressed by Equation 7 and determine whether or not the sound source exists in the target direction using this correlation function R _ij Thus, it is different from the acoustic input device of the third embodiment. In addition, about the component similar to Embodiment 3, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The correlation function R _{ij in Equation} 7 is an autocorrelation function when i = j, and a cross-correlation function when i ≠ j.

The sound source direction determination unit 21a of the present embodiment is different from the embodiment 3, the reference observation signal x0 (k, m) a reference observation signal x0 (k, m) for the autocorrelation function _{R 00} between the first observation signals x1 The relative ratio (R ₀₁ / R ₀₀ ) of the cross-correlation function R ₀₁ of (k, m) is included in the first preset range, and the reference observation signal x 0 (k, m) with respect to the autocorrelation function R ₀₀ When the relative ratio (R ₀₂ / R ₀₀ ) of the cross-correlation function R ₀₂ between the second observation signal x 2 (k, m) satisfies the condition included in the preset second range, the sound source is in the target direction. It is determined that it exists. On the other hand, when the above condition is not satisfied, the sound source direction determination unit 21a determines that the sound source does not exist in the target direction.

Here, the first range of the present embodiment is a range greater than the initially set threshold value ξ and 1 or less (ξ <R ₀₁ / R ₀₀ ≦ 1). The second range of the present embodiment is also a range greater than the initially set threshold value ξ and 1 or less (ξ <R ₀₂ / R ₀₀ ≦ 1).

As described above, according to the present embodiment, the autocorrelation function R _{00 of the} reference observation signal x 0 (k, m), the reference observation signal x 0 (k, m), and the first and second observation signals x 1 (k, m), x 2. By using the cross-correlation functions R ₀₁ and R ₀₂ of (k, m), the influence of uncorrelated noise can be reduced and a high S / N ratio can be achieved, and whether or not the sound source exists in the target direction. The determination accuracy can be increased.

(Embodiment 5)
In the acoustic input devices of the first and third embodiments, the output signal y (k, m) (the power value Py (k) of the output signal is not as shown in FIG. 10B) with respect to the direction in which the sound source exists. It will be continuous.

  Therefore, in the sound input device according to the fifth embodiment, when the sound source direction determination unit 21 illustrated in FIG. 1 determines that the sound source does not exist in the target direction, the sound input device determines whether the sound source exists in the vicinity of the target direction. On the other hand, when the output calculation unit 22 determines that the sound source exists in the vicinity of the target direction by the sound source direction determination unit 21, a continuous change that monotonously decreases between the first amplification factor G1 and the second amplification factor G2. The sound input device is different from the sound input device according to the first embodiment in that the synthesized signal is amplified and output with the amplification factor of the characteristic. In addition, about the component similar to Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

As shown in FIG. 12, the amplification factor G is such that both the first and second observation power values Px1 (k) and Px2 (k) are larger than a predetermined threshold value Pth, and the relative ratio | 10log ₁₀ (Px1 (k) / Px2 (k)) | is 0 or more and less than the threshold value ε (0 ≦ | 10log ₁₀ (Px1 (k) / Px2 (k)) | <ε), as in the first embodiment, the first gain G1 Become.

On the other hand, when the relative ratio | 10log ₁₀ (Px1 (k) / Px2 (k)) | is equal to or greater than the threshold ε, first, the relative ratio | 10log ₁₀ (Px1 (k) / Px2 (k)) | When the threshold is less than ε1 (ε1> ε) (ε ≦ | ₁₀ log ₁₀ (Px1 (k) / Px2 (k)) | <ε), it is determined that the sound source exists in the vicinity of the target direction, and the gain G decreases monotonously. It varies according to the function f. Subsequently, when the relative ratio | 10log ₁₀ (Px1 (k) / Px2 (k)) | is equal to or greater than the threshold ε1 (ε1 ≦ | 10log ₁₀ (Px1 (k) / Px2 (k)) |), the sound source is in the target direction. Is determined to be present at a distant position, and the amplification factor G becomes the second amplification factor G2.

  As described above, according to the present embodiment, it is possible to prevent the amplification factor G for amplifying the combined signal (x1 (k, m) + x2 ′ (k, m)) from becoming discontinuous depending on the direction in which the sound source exists. As a result, the output signal y (k, m) (power value Py (k) of the output signal) can always be a continuous value (see FIG. 13).

As for the acoustic input device of the second embodiment, the amplification factor G is the first amplification factor G1 as in the second embodiment when the cross-correlation function R ₁₂ > threshold value Rth as shown in FIG. .

On the other hand, if it is not the cross-correlation function _{R 12>} threshold Rth, first, when the cross-correlation function _{R 12} is the threshold value Rth1 (Rth1 <Rth) greater than threshold value Rth following (Rth1 _{<R 12} ≦ Rth), the sound source is object direction It is determined that it exists in the vicinity, and the amplification factor G varies according to the monotonically increasing function e. Subsequently, when the cross-correlation function _{R 12} is 0 or larger than the threshold Rth1 less (0 ≦ _{R 12} ≦ Rth1), the sound source is determined to be present at a position distant from the destination direction, the gain G is a second amplification factor G2 It becomes. Note that the sensitivities of the first directional microphone 10, the second directional microphone 11, and the omnidirectional microphone 12 are all equal.

  In the acoustic input device according to the third embodiment, the amplification factor G has a relative ratio (Px1 (k) / Px0 (k)) and a relative ratio (Px2 (k) / Px0 (k) as shown in FIG. ) Is greater than the threshold value δ and equal to or less than 1 (δ <Px1 (k) / Px0 (k) ≦ 1 and δ <Px2 (k) / Px0 (k) ≦ 1), as in the third embodiment. A gain G1 of 1.

  On the other hand, when the relative ratio (Px1 (k) / Px0 (k)) and the relative ratio (Px2 (k) / Px0 (k)) are not within the above ranges, first, the relative ratio (Px1 (k) / Px0 (k) )) Or the relative ratio (Px2 (k) / Px0 (k)) is greater than the threshold δ1 (δ1 <δ) and less than or equal to the threshold δ (δ1 <Px1 (k) / Px0 (k) ≦ δ or δ1 <Px2 When (k) / Px0 (k) ≦ δ), it is determined that the sound source exists in the vicinity of the target direction, and the amplification factor G varies according to the monotonically increasing function g. Subsequently, either the relative ratio (Px1 (k) / Px0 (k)) or the relative ratio (Px2 (k) / Px0 (k)) is 0 or more and the threshold δ1 or less (0 ≦ Px1 (k) / Px0 (k) ) ≦ δ1 or 0 ≦ Px2 (k) / Px0 (k) ≦ δ1), it is determined that the sound source exists at a position away from the target direction, and the amplification factor G becomes the second amplification factor G2. Note that the sensitivities of the first directional microphone 10, the second directional microphone 11, and the omnidirectional microphone 12 are all equal.

In the acoustic input device according to the fourth embodiment, as shown in FIG. 16, the amplification factor G has a relative ratio (R ₀₁ / R ₀₀ ) and a relative ratio (R ₀₂ / R ₀₀ ) that are both higher than a threshold ξ. In the case of large 1 or less (ξ <R ₀₁ / R ₀₀ ≦ 1 and ξ <R ₀₂ / R ₀₀ ≦ 1), the first amplification factor G1 is obtained as in the fourth embodiment.

On the other hand, when the relative ratio (R ₀₁ / R ₀₀ ) and the relative ratio (R ₀₂ / R ₀₀ ) are not in the above ranges, first, the relative ratio (R ₀₁ / R ₀₀ ) or the relative ratio (R ₀₂ / R ₀₀ ) If either threshold ξ1 (ξ1 <ξ) greater than threshold value xi] or less _{(ξ1 <R 01 / R 00} ≦ ξ or _{ξ1 <R 02 / R 00 ≦} ξ) of determining a sound source is present in the vicinity of the target direction The amplification factor G varies according to the monotonically increasing function h. Subsequently, either the relative ratio (R ₀₁ / R ₀₀ ) or the relative ratio (R ₀₂ / R ₀₀ ) is 0 or more and the threshold ξ1 or less (0 ≦ R ₀₁ / R ₀₀ ≦ ξ 1 or 0 ≦ R ₀₂ / R ₀₀ ≦ In the case of ξ1), it is determined that the sound source exists at a position away from the target direction, and the amplification factor G becomes the second amplification factor G2. Note that the sensitivities of the first directional microphone 10, the second directional microphone 11, and the omnidirectional microphone 12 are all equal.

  As described above, even in the acoustic input device as in the third and fourth embodiments, the amplification factor G for amplifying the combined signal (x1 (k, m) + x2 ′ (k, m)) as in the fifth embodiment. Can be prevented from becoming discontinuous depending on the direction in which the sound source exists. As a result, unlike FIG. 10B, the output signal y (k, m) (power value Py (k) of the output signal) is obtained. It can always be a continuous value.

(Embodiment 6)
In the first to fifth embodiments, the case of one sound source has been described. In the sixth embodiment, the case of two sound sources will be described. Here, as a combination of a plurality of sound sources, (1) only a target sound source exists, (2) a target sound source and one noise source exist, and (3) a target sound source and two noise sources exist. (4) No target sound source and no noise source, (5) No target sound source and only one noise source, (6) No target sound source and two noise sources May exist. Among them, the combination of the two sound sources is the case of (2) and (6). Specifically, as shown in FIG. 17A, the target sound source S exists in an area where the sound collection areas of the first directional microphone 10 and the second directional microphone 11 overlap, and the first directional microphone. A case where the noise source N1 exists only in the ten sound collection regions will be described.

In the case shown in FIG. 17A, among the sound source direction determination conditions of the first embodiment, Px1 (k)> Pth (first condition) and Px2 (k)> Pth (second condition) are satisfied, The second observation signal x2 (t) of the second directional microphone 11 includes only a signal based on the target sound source S, whereas the first observation signal x1 (t) of the first directional microphone 10 includes Since not only the target sound source S but also a signal based on the noise source N1 is included, | 10log ₁₀ (Px1 (k) / Px2 (k) | <ε (third condition) is not satisfied.

As described above, when the first and second conditions are satisfied but the third condition is not satisfied, the sound source direction determination condition R ₁₂ > Rth (fourth condition) of the second embodiment is further used. The target sound source S exists in an area where the sound collection areas of the first and second directional microphones 10 and 11 overlap, and the noise source N1 exists only in the sound collection area of the first directional microphone 10. However, since the signal based on the target sound source S is included in the observation signals x1 (t) and x2 (t) of both the first and second directional microphones 10 and 11, the fourth condition is satisfied. Therefore, the sound source direction determination unit 21 can determine that the target sound source S exists in an area where the sound collection regions of the first and second directional microphones 10 and 11 overlap.

  Subsequently, the sound source direction determination unit 21 needs to determine in which sound collection area the noise source N1 is present among the first and second directional microphones 10 and 11. Therefore, as shown in FIG. 17A, the omnidirectional microphone 12 is disposed between the first directional microphone 10 and the second directional microphone 11. Since the omnidirectional microphone 12 is omnidirectional, the reference observation signal x0 (t) includes a signal based on both the target sound source S and the noise source N1. Therefore, the sound source direction determination unit 21 among the observed power values Px1 (k) and Px2 (k) of the first and second directional microphones 10 and 11, δ <Pxi (k) / Px0 (k) ≦ 1 ( i = 1, 2) It is determined that the noise source N1 is present in the sound collection region of the first and second directional microphones 10 and 11 satisfying (fifth condition).

  When it is determined that the target sound source S exists in the area where the sound collection areas of the first and second directional microphones 10 and 11 overlap and the noise source N1 exists only in the sound collection area of the first directional microphone 10, The output calculation unit 22 amplifies the discrete value x2 (k, m) of the second observation signal of the second directional microphone 11 including only the signal based on the target sound source S with the amplification factor G1, and outputs the output signal y (k , M) = G1 × x2 (k, m) is output.

  On the other hand, when it is determined that the target sound source S does not exist in the area where the sound collection areas of the first and second directional microphones 10 and 11 overlap, the output calculation unit 22 selects the first and second directional microphones 10 and 11. A composite signal (x1 (k, m) + x2 (k, m)) of the discrete values x1 (k, m) and x2 (k, m) of the 11 observation signals is amplified with an amplification factor G2 (G1> G2). Output signal y (k, m) = G2 (x1 (k, m) + x2 (k, m)) is output.

  As described above, according to the present embodiment, the target sound source S exists in the area where the sound collection areas of the first and second directional microphones 10 and 11 overlap, and the noise source N1 is the first and second directional microphones 10 and 11. Even when the signal exists only in one of the sound collection regions, only the signal based on the target sound source S can be amplified and output.

  As a modification of the sixth embodiment, the output signal y (k, m) can be output as follows. The sound source direction determination unit 21 includes the target sound source S in an area where the sound collection areas of the first and second directional microphones 10 and 11 overlap, and the noise source N1 is present only in the sound collection area of the first directional microphone 10. If it is determined that it exists, the first and second directional microphones 10 and 11 are observed after the directional axis of the first directional microphone 10 is tilted until the third condition is satisfied as shown in FIG. A composite signal (x1 (k, m) + x2 (k, m)) of the discrete values x1 (k, m) and x2 (k, m) of the signal is amplified by the amplification factor G1, and the output signal y (k, m) = G1 (x1 (k, m) + x2 (k, m)) is output. The case where the target sound source S does not exist in the area where the sound collection areas of the first and second directional microphones 10 and 11 overlap is the same as that in the sixth embodiment.

(Embodiment 7)
In the sixth embodiment, the case of two sound sources has been described. In the seventh embodiment, the case of three sound sources will be described. The combination of the three sound sources is (3) only when the target sound source and the two noise sources exist, but it is necessary to distinguish between the two sound sources ((2) and (6)). Specifically, as shown in FIG. 18A, the target sound source S exists in an area where the sound collection areas of the first and second directional microphones 10 and 11 overlap, and the sound collection of the first directional microphone 10 is performed. A case where the noise source N1 exists only in the area and the noise source N2 exists only in the sound collection area of the second directional microphone 11 will be described.

In the case shown in FIG. 18A, among the sound source direction determination conditions of the first embodiment, Px1 (k)> Pth (first condition) and Px2 (k)> Pth (second condition) are satisfied. The first observation signal x1 (t) of one directional microphone 10 includes a signal based on the target sound source S and the noise source N1, and the second observation signal x2 (t) of the second directional microphone 11 is included in the first observation signal x1 (t). Includes a signal based on the target sound source S and the noise source N2, and thus | 10log ₁₀ (Px1 (k) / Px2 (k) | <ε (third condition) is not always satisfied.

As described above, when the first and second conditions are satisfied but the third condition is not satisfied, the sound source direction determination condition R ₁₂ > Rth (fourth condition) of the second embodiment is further used. The target sound source S exists in an area where the sound collection areas of the first and second directional microphones 10 and 11 overlap, the noise source N1 exists only in the sound collection area of the first directional microphone 10, and the second Even when the noise source N2 exists only in the sound collection region of the directional microphone 11, the signal based on the target sound source S is the observation signal x1 (t of both the first and second directional microphones 10 and 11). ), X2 (t), the fourth condition is satisfied. Therefore, the sound source direction determination unit 21 can determine that the target sound source S exists in an area where the sound collection regions of the first and second directional microphones 10 and 11 overlap.

  Subsequently, the sound source direction determination unit 21 determines whether the noise source N1 is present in any one of the sound collection regions of the first and second directional microphones 10 and 11 as in the sixth embodiment, or in the present embodiment. Thus, it is necessary to determine whether different noise sources N1 and N2 exist in the sound collection areas of the first and second directional microphones 10 and 11, respectively. Therefore, as shown in FIG. 18A, the omnidirectional microphone 12 is disposed between the first directional microphone 10 and the second directional microphone 11. Since the omnidirectional microphone 12 is omnidirectional, the reference observation signal x0 (t) includes a signal based on the target sound source S and the noise sources N1 and N2, and the first directional microphone 10 includes the target sound source S and the noise source N1. Is included in the first observation signal x1 (t), and the second directional microphone 11 includes a signal based on the target sound source S and the noise source N2 in the second observation signal x2 (t). Therefore, the sound source direction determination unit 21 includes the omnidirectional microphone 12 and the first directivity when the noise sources N1 and N2 are outside the sound collection region of the first directional microphone 10 and the second directional microphone 11. The observed power values Px1 (k), Px2 (1) of the first and second directional microphones 10 and 11 with the ratio δ2 of the observed power values of the directional microphone 10 or the omnidirectional microphone 12 and the second directional microphone 11 as a threshold. k) satisfies δ2 <Pxi (k) / Px0 (k) ≦ δ (i = 1, 2) (fifth condition), respectively, the sound collecting areas of the first and second directional microphones 10 and 11 respectively. It is determined that different noise sources N1 and N2 exist.

  The target sound source S exists in an area where the sound collection areas of the first and second directional microphones 10 and 11 overlap, and the noise sources N1 and N2 are collected by the first directional microphone 10 and the second directional microphone 11, respectively. When it is determined that the sound source exists only in the sound region, as shown in FIG. 18A, the noise sources N1 and N2 are separated from the central axis of the area where the sound collection regions of the first and second directional microphones 10 and 11 overlap. When the distance is greater than Max (α1 / 2, α2 / 2), as shown in FIG. 18B, the directional axes of the first and second directional microphones 10 and 11 are tilted until the third condition is satisfied. Only signals based on the target sound source S can be collected by the first and second directional microphones 10 and 11. At this time, the output calculation unit 22 is a composite signal (x1 (k, m) + x2) of the discrete values x1 (k, m) and x2 (k, m) of the observation signals of the first and second directional microphones 10 and 11. (K, m)) is amplified with an amplification factor G1, and an output signal y (k, m) = G1 (x1 (k, m) + x2 (k, m)) is output.

  On the other hand, when it is determined that the target sound source S does not exist in the area where the sound collection areas of the first and second directional microphones 10 and 11 overlap, the output calculation unit 22 selects the first and second directional microphones 10 and 11. A composite signal (x1 (k, m) + x2 (k, m)) of the discrete values x1 (k, m) and x2 (k, m) of the first and second observation signals of 11 is amplified by a gain G2 (G1> G2 ) And output an output signal y (k, m) = G2 (x1 (k, m) + x2 (k, m)).

  As described above, according to the present embodiment, the target sound source S exists in the area where the sound collection areas of the first and second directional microphones 10 and 11 overlap, and the first directional microphone 10 and the second directional microphone 11 are present. Even when different noise sources N1 and N2 exist in the respective sound collection regions, signals based on the target sound source S can be emphasized and output.

  As shown in FIGS. 19A and 19B, at least one of the noise source N1 and the noise source N2 is Max from the central axis of the area where the sound collection areas of the first and second directional microphones 10 and 11 overlap. If they are not separated by (α1 / 2, α2 / 2) or more, even if the directional axes of the first and second directional microphones 10 and 11 are tilted, only the signal of the target sound source S cannot be collected. However, the signal based on the target sound source S is included in both the first and second observation signals x1 (t) and x2 (t), and the signal based on the noise source N1 is only in the first observation signal x1 (t). Since the signal based on the noise source N2 is included only in the second observation signal x2 (t), a composite signal (x1) of the discrete values x1 (k, m) and x2 (k, m) of the first and second observation signals. By amplifying (k, m) + x2 (k, m)) with the amplification factor G1 and outputting the signal, the signal based on the target sound source S can be emphasized as compared with the case where the sound is collected by the omnidirectional microphone 12 alone. .

  Note that the sound input devices of Embodiments 6 and 7 perform the determination operation as shown in FIG. 20 to (1) when only the target sound source exists, or (2) when there is the target sound source and one noise source. (3) When there is a target sound source and two noise sources, (4) When there is neither a target sound source nor a noise source, (5) When there is no target sound source and there is only one noise source, (6 ) The case where there is no target sound source and there are two noise sources can be determined separately.

It is a block diagram which shows the structure of the acoustic input device of Embodiment 1,2. It is a figure for demonstrating operation | movement of an acoustic input device same as the above. It is a figure for demonstrating the characteristic of a 1st directional microphone and a 2nd directional microphone in the acoustic input device of Embodiments 1-8. It is a figure for demonstrating phase adjustment in an acoustic input device same as the above. It is a figure for demonstrating phase adjustment in an acoustic input device same as the above. 3 is a flowchart illustrating an operation of the sound input device according to the first embodiment. It is a figure for demonstrating the characteristic of the modification of a 1st directional microphone and a 2nd directional microphone in the acoustic input device of Embodiments 1-8. It is a figure for demonstrating the characteristic of the other modification of a 1st directional microphone and a 2nd directional microphone in the acoustic input device of Embodiments 1-8. FIG. 10 is a diagram for explaining the operation of the acoustic input device according to the second embodiment. It is a figure for demonstrating operation | movement of the acoustic input device of Embodiment 3. It is a block diagram which shows the structure of the acoustic input device of Embodiment 3,4. It is a figure which shows the amplification factor in the acoustic input device of Embodiment 5. It is a figure which shows the output signal in an acoustic input device same as the above. It is a figure which shows the gain in the acoustic input device of the modification same as the above. It is a figure which shows the gain in the acoustic input device of the other modification same as the above. It is a figure which shows the gain in the acoustic input device of the other modification same as the above. FIG. 10 is a diagram for explaining the operation of the sound input device according to the sixth embodiment. FIG. 10 is a diagram for explaining the operation of the acoustic input device according to the seventh embodiment. It is a figure for demonstrating operation | movement of an acoustic input device same as the above. 10 is a flowchart illustrating an operation of the acoustic input device according to the sixth and seventh embodiments.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1a Sound collecting part 10 1st directional microphone 11 2nd directional microphone 12 Non-directional microphone 2, 2a Signal processing part 20, 20a Phase difference correction part 21, 21a Sound source direction determination part 22 Output calculation part

Claims (10)

Each generates an observation signal based on the sound waves received wave and the reception of sound waves from a sound source to be present in the sound collecting area having a sound collection region of the directivity angle of the constant Tokoro, between part of each sound collecting area A first directional microphone and a second directional microphone installed in close proximity so as to overlap each other including a predetermined target direction ;
The first observation signal is received from the first directional microphone, the second observation signal is received from the second directional microphone, and the order of the received first observation signal and second observation signal is received . a phase difference correcting unit for correcting only the phase difference between the first observation signal and the second observation signal when retardation of the sound source is present in the target direction,
And using said the first observation signal and the second observation signal after being corrected by the phase difference correcting unit, the sound source determines the sound source direction determination unit that determines whether present in the target direction,
When the sound source direction determination unit determines that the sound source exists in the target direction, the first observation signal generated by the first directional microphone and the second directional microphone generated by the first directional microphone While the phase difference from the second observation signal is corrected by the phase difference, the combined signal of the first observation signal and the second observation signal is amplified by the first amplification factor and output, If the sound source by the sound source direction determination unit determines that there is no in the target direction, the front Kigo forming signal and an output calculation unit for amplifying and outputting at said first amplification factor is smaller than the amplification factor ,
The power value of the first observation signal after being corrected by the phase difference correction unit is set as a first observation power value, and the power value of the second observation signal after being corrected by the phase difference correction unit is The second observed power value,
The sound source direction determination unit has both the first observation power value and the second observation power value larger than a predetermined threshold, and the first observation power value and the second observation power value. When the condition that the relative ratio is less than a predetermined value is satisfied, the sound source is determined to exist in the target direction. On the other hand, if the condition is not satisfied, the sound source is determined not to exist in the target direction. An acoustic input device. Each has a sound collection area of a predetermined directivity angle, receives a sound wave from a sound source existing in the sound collection area, generates an observation signal based on the received sound wave, and a part of each sound collection area A first directional microphone and a second directional microphone installed in close proximity so as to overlap each other including a predetermined target direction;
The first observation signal is received from the first directional microphone, the second observation signal is received from the second directional microphone, and the order of the received first observation signal and second observation signal is received. A phase difference correction unit that corrects the phase difference by a phase difference between the first observation signal and the second observation signal when a sound source is present in the target direction;
A sound source direction determination unit that determines whether or not the sound source is present in the target direction using the first observation signal and the second observation signal after being corrected by the phase difference correction unit;
When the sound source direction determination unit determines that the sound source exists in the target direction, the first observation signal generated by the first directional microphone and the second directional microphone generated by the first directional microphone While the phase difference from the second observation signal is corrected by the phase difference, the combined signal of the first observation signal and the second observation signal is amplified by the first amplification factor and output, When the sound source direction determination unit determines that the sound source does not exist in the target direction, an output calculation unit that amplifies and outputs the combined signal with an amplification factor smaller than the first amplification factor,
The sound source direction determination unit uses the discrete value x1 of the first observation signal and the discrete value x2 of the second observation signal after being corrected by the phase difference correction unit, and is a correlation function R expressed by Formula 1. _ij (i, j = 1, 2) is obtained, and when the cross-correlation function R ₁₂ satisfies a condition that is equal to or greater than a predetermined set value set based on the auto -correlation function R ₁₁ or the auto-correlation function R ₂₂ , there while determined to exist in the target direction, does not satisfy the condition, features and be Ruoto sound input device that determines that the sound source is not present in the target direction.

Each has a sound collection area of a predetermined directivity angle, receives a sound wave from a sound source existing in the sound collection area, generates an observation signal based on the received sound wave, and a part of each sound collection area A first directional microphone and a second directional microphone installed in close proximity so as to overlap each other including a predetermined target direction;
An omnidirectional microphone installed at an intermediate position between the first directional microphone and the second directional microphone to receive a sound wave from the sound source and generate a reference observation signal based on the received sound wave;
The first observation signal is received from the first directional microphone, the second observation signal is received from the second directional microphone, and the order of the received first observation signal and second observation signal is received. A phase difference correction unit that corrects the phase difference by a phase difference between the first observation signal and the second observation signal when a sound source is present in the target direction;
A sound source direction determination unit that determines whether or not the sound source is present in the target direction using the first observation signal and the second observation signal after being corrected by the phase difference correction unit;
When the sound source direction determination unit determines that the sound source exists in the target direction, the first observation signal generated by the first directional microphone and the second directional microphone generated by the first directional microphone While the phase difference from the second observation signal is corrected by the phase difference, the combined signal of the first observation signal and the second observation signal is amplified by the first amplification factor and output, When the sound source direction determination unit determines that the sound source does not exist in the target direction, an output calculation unit that amplifies and outputs the combined signal with an amplification factor smaller than the first amplification factor,
The phase difference correction unit further receives the reference observation signal, and uses the phase difference between the received reference observation signal and the received first observation signal as a reference observation signal when a sound source exists in the target direction. And correct the phase difference between the first observed signal and
The power value of the first observation signal after being corrected by the phase difference correction unit is set as a first observation power value, and the power value of the second observation signal after being corrected by the phase difference correction unit is As a second observation power value, the power value of the reference observation signal after being corrected by the phase difference correction unit as a reference observation power value,
The sound source direction determination unit includes a relative ratio of the first observation power value to the reference observation power value in a preset first range, and the second observation power with respect to the reference observation power value. If the relative ratio of values satisfies the condition included in the preset second range, it is determined that the sound source exists in the target direction, and if the condition is not satisfied, the sound source exists in the target direction. features and to Ruoto sound input device that determines not to. Each has a sound collection area of a predetermined directivity angle, receives a sound wave from a sound source existing in the sound collection area, generates an observation signal based on the received sound wave, and a part of each sound collection area A first directional microphone and a second directional microphone installed in close proximity so as to overlap each other including a predetermined target direction;
An omnidirectional microphone installed at an intermediate position between the first directional microphone and the second directional microphone to receive a sound wave from the sound source and generate a reference observation signal based on the received sound wave;
The first observation signal is received from the first directional microphone, the second observation signal is received from the second directional microphone, and the order of the received first observation signal and second observation signal is received. A phase difference correction unit that corrects the phase difference by a phase difference between the first observation signal and the second observation signal when a sound source is present in the target direction;
A sound source direction determination unit that determines whether or not the sound source is present in the target direction using the first observation signal and the second observation signal after being corrected by the phase difference correction unit;
When the sound source direction determination unit determines that the sound source exists in the target direction, the first observation signal generated by the first directional microphone and the second directional microphone generated by the first directional microphone While the phase difference from the second observation signal is corrected by the phase difference, the combined signal of the first observation signal and the second observation signal is amplified by the first amplification factor and output, When the sound source direction determination unit determines that the sound source does not exist in the target direction, an output calculation unit that amplifies and outputs the combined signal with an amplification factor smaller than the first amplification factor,
The phase difference correction unit extracts a discrete value of the received first observation signal at a predetermined time interval, extracts a discrete value of the received second observation signal at the predetermined time interval, and extracts the reference observation signal. And the discrete value of the reference observation signal is extracted at the predetermined time interval, and the phase difference between the extracted discrete value of the first observation signal and the second observation signal is expressed by the sound source in the target direction. The phase difference between the discrete value of the extracted reference observation signal and the first observation signal is corrected by the phase difference between the first observation signal and the second observation signal in the case where the sound source is present in the target direction. Correct only the phase difference between the reference observation signal and the first observation signal when present,
The sound source direction determination unit includes a discrete value x1 of the first observation signal after correction by the phase difference correction unit, and a discrete value x2 of the second observation signal after correction by the phase difference correction unit. And a correlation function R _ij (i, j = 0, 1, 2) expressed by the following equation (2) using the discrete value x0 of the reference observation signal after being corrected by the phase difference correction unit, and the autocorrelation function R _{A condition in which} a relative ratio of the cross-correlation function R _{01 with} respect to ₀₀ is included in a preset first range and a relative ratio of the cross-correlation function R _{02 with} respect to the autocorrelation function R ₀₀ is included in a preset second range. If satisfying, while determines that the sound source is present in the target direction, it does not satisfy the condition, features and be Ruoto sound input device that determines that the sound source is not present in the target direction.

Each has a sound collection area of a predetermined directivity angle, receives a sound wave from a sound source existing in the sound collection area, generates an observation signal based on the received sound wave, and a part of each sound collection area A first directional microphone and a second directional microphone installed in close proximity so as to overlap each other including a predetermined target direction;
The first observation signal is received from the first directional microphone, the second observation signal is received from the second directional microphone, and the order of the received first observation signal and second observation signal is received. A phase difference correction unit that corrects the phase difference by a phase difference between the first observation signal and the second observation signal when a sound source is present in the target direction;
A sound source direction determination unit that determines whether or not the sound source is present in the target direction using the first observation signal and the second observation signal after being corrected by the phase difference correction unit;
When the sound source direction determination unit determines that the sound source exists in the target direction, the first observation signal generated by the first directional microphone and the second directional microphone generated by the first directional microphone While the phase difference from the second observation signal is corrected by the phase difference, the combined signal of the first observation signal and the second observation signal is amplified by the first amplification factor and output, When the sound source direction determination unit determines that the sound source does not exist in the target direction, an output calculation unit that amplifies and outputs the combined signal with an amplification factor smaller than the first amplification factor,
The sound source direction determination unit determines whether the sound source exists in the vicinity of the target direction when it is determined that the sound source does not exist in the target direction.
When the sound source direction determination unit determines that the sound source exists in the vicinity of the target direction, the output calculation unit has a continuously changing characteristic that monotonously decreases from the first amplification factor as the distance from the target direction increases. features and to Ruoto sound input device to output an amplification factor and amplifies the combined signal. Each has a sound collection area of a predetermined directivity angle, receives a sound wave from a sound source existing in the sound collection area, generates an observation signal based on the received sound wave, and a part of each sound collection area A first directional microphone and a second directional microphone installed in close proximity so as to overlap each other including a predetermined target direction;
An omnidirectional microphone installed at an intermediate position between the first directional microphone and the second directional microphone to receive a sound wave from the sound source and generate a reference observation signal based on the received sound wave;
The first observation signal is received from the first directional microphone, the second observation signal is received from the second directional microphone, and the order of the received first observation signal and second observation signal is received. A phase difference correction unit that corrects the phase difference by a phase difference between the first observation signal and the second observation signal when a sound source is present in the target direction;
A sound source direction determination unit that determines whether or not the sound source is present in the target direction using the first observation signal and the second observation signal after being corrected by the phase difference correction unit;
When the sound source direction determination unit determines that the sound source exists in the target direction, the first observation signal generated by the first directional microphone and the second directional microphone generated by the first directional microphone While the phase difference from the second observation signal is corrected by the phase difference, the combined signal of the first observation signal and the second observation signal is amplified by the first amplification factor and output, When the sound source direction determination unit determines that the sound source does not exist in the target direction, an output calculation unit that amplifies and outputs the combined signal with an amplification factor smaller than the first amplification factor,
The phase difference correction unit further receives the reference observation signal, and uses the phase difference between the received reference observation signal and the received first observation signal as a reference observation signal when a sound source exists in the target direction. And correct the phase difference between the first observed signal and
The power value of the first observation signal after being corrected by the phase difference correction unit is set as a first observation power value, and the power value of the second observation signal after being corrected by the phase difference correction unit is The second observation power value, the power value of the reference observation signal after being corrected by the phase difference correction unit as a reference observation power value,
The sound source direction determination unit
Both the first observation power value and the second observation power value are greater than a predetermined threshold, and the relative ratio between the first observation power value and the second observation power value is a predetermined value. When the value is equal to or greater than a first set value, a cross-correlation function between the first observation signal and the second observation signal is an autocorrelation function of the first observation signal or a self-correlation of the second observation signal. When a condition that is equal to or greater than a predetermined second set value obtained from a correlation function is satisfied, the sound source is determined to be present in each of the target direction and other regions other than the target direction, but the condition is not satisfied , Determine that the sound source does not exist in the target direction,
When it is determined that the sound source exists in each of the target direction and the other region, a relative ratio of the first observation power value to the reference observation power value is included in a preset range, and the reference When the relative ratio of the second observed power value to the observed power value is not included in the range, it is determined that the sound source exists in a sound collection region of the first directional microphone among the other regions, The relative ratio of the second observed power value to the reference observed power value is included in the range, and the relative ratio of the first observed power value to the reference observed power value is not included in the range, other features and to Ruoto sound input device that determines that the sound source to the sound collecting area of the second directional microphone is present in the region. When the sound source exists in either the sound collection region of the first directional microphone or the sound collection region of the second directional microphone among the other regions by the sound source direction determination unit. The sound input device according to claim 6 , wherein if determined, an observation signal of a directional microphone in which the sound source does not exist in the sound collection region is amplified by the first amplification factor and output . Drive means for tilting the directional axis of the first directional microphone or the second directional microphone;
The sound source direction determination unit includes the sound source in the target direction, and a sound collection region of the first directional microphone or a sound collection region of the second directional microphone among the other regions. If it is determined that either one is present, the driving means is controlled until a condition that a relative ratio between the first observed power value and the second observed power value is less than the first set value is satisfied,
The output calculation unit determines that the sound source is present in the sound collection region of the first directional microphone and the sound collection region of the second directional microphone by the sound source direction determination unit after the driving unit is driven. In this case, a synthesized signal of the first observation signal and the second observation signal after driving the driving means is amplified and output with the first amplification factor, while the sound source direction determination unit When it is determined that the signal does not exist in the target direction, a second amplification smaller than the first amplification factor is obtained by combining a combined signal of the first observation signal and the second observation signal after driving the driving unit. The sound input device according to claim 6 , wherein the sound input device outputs the amplified signal at a rate . Each has a sound collection area of a predetermined directivity angle, receives a sound wave from a sound source existing in the sound collection area, generates an observation signal based on the received sound wave, and a part of each sound collection area A first directional microphone and a second directional microphone installed in close proximity so as to overlap each other including a predetermined target direction;
An omnidirectional microphone installed at an intermediate position between the first directional microphone and the second directional microphone to receive a sound wave from the sound source and generate a reference observation signal based on the received sound wave;
The first observation signal is received from the first directional microphone, the second observation signal is received from the second directional microphone, and the order of the received first observation signal and second observation signal is received. A phase difference correction unit that corrects the phase difference by a phase difference between the first observation signal and the second observation signal when a sound source is present in the target direction;
A sound source direction determination unit that determines whether or not the sound source is present in the target direction using the first observation signal and the second observation signal after being corrected by the phase difference correction unit;
When the sound source direction determination unit determines that the sound source exists in the target direction, the first observation signal generated by the first directional microphone and the second directional microphone generated by the first directional microphone While the phase difference from the second observation signal is corrected by the phase difference, the combined signal of the first observation signal and the second observation signal is amplified by the first amplification factor and output, When the sound source direction determination unit determines that the sound source does not exist in the target direction, an output calculation unit that amplifies and outputs the combined signal with an amplification factor smaller than the first amplification factor,
The phase difference correction unit further receives the reference observation signal, and uses the phase difference between the received reference observation signal and the received first observation signal as a reference observation signal when a sound source exists in the target direction. And correct the phase difference between the first observed signal and
The power value of the first observation signal after being corrected by the phase difference correction unit is set as a first observation power value, and the power value of the second observation signal after being corrected by the phase difference correction unit is As a second observation power value, the power value of the reference observation signal after being corrected by the phase difference correction unit as a reference observation power value,
The sound source direction determination unit
When both the first observation power value and the second observation power value are larger than a predetermined threshold, the cross-correlation function between the first observation signal and the second observation signal is When a condition that is equal to or greater than a predetermined set value obtained from the autocorrelation function of one observation signal or the autocorrelation function of the second observation signal is satisfied, the sound source is in the target direction and other regions other than the target direction. While determining that each exists, when the condition is not satisfied, it is determined that the sound source does not exist in the target direction,
When it is determined that the sound source exists in each of the target direction and the other region, a relative ratio of the first observation power value to the reference observation power value, and the second observation power to the reference observation power value When each of the relative ratios of the values is included in a preset range, it is determined that the sound source exists in each of the sound collection regions of the first directional microphone and the second directional microphone, be Ruoto sound input device. Drive means for inclining directional axes of the first directional microphone and the second directional microphone;
The sound source direction determination unit includes the sound source in the target direction, and further includes a sound collection region of the first directional microphone and a sound collection region of the second directional microphone among the other regions. If it is determined that the sound source exists in any of the two directions, the two sound sources in the other areas are separated from the target direction by at least one half of the maximum value of the directivity angles of the first directional microphone and the second directional microphone. And controlling the driving means until a condition that a relative ratio between the first observed power value and the second observed power value is less than a predetermined set value is satisfied,
The output calculation unit determines that the sound source is present in the sound collection region of the first directional microphone and the sound collection region of the second directional microphone by the sound source direction determination unit after the driving unit is driven. In this case, a synthesized signal of the first observation signal and the second observation signal after driving the driving means is amplified and output with the first amplification factor, while the sound source direction determination unit When it is determined that the signal does not exist in the target direction, a second amplification smaller than the first amplification factor is obtained by combining a combined signal of the first observation signal and the second observation signal after driving the driving unit. The sound input device according to claim 9 , wherein the sound input device outputs the amplified signal at a rate .

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