JP5032960B2 - Acoustic input device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To emphasize and output sound from a sound source present in an object region. <P>SOLUTION: A phase difference correction part 20 extracts discrete values of first and second observation signals generated by first and second microphone modules 10 and 11. A sound source position determination part 21 calculates first and second observation power values from the discrete values of the first and second observation signals. When at least one of the first and second observation values is not larger than a threshold value, it is determined that the sound source is not present in the object region and, when both the first and second observation power values are larger than the threshold value, it is determined that the sound source is present in the object region. An output calculation part 22 outputs a synthesized signal obtained by superposing the first and second observation signals after correcting only the phase difference in the case where the sound source is present in the object region when the sound source is not present in the object region, and outputs the synthesized signal by amplifying it with an amplification factor larger than that in the case where the sound source is not present in the object region when the sound source is present in the object region. <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 area.

  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 super-directional microphone having a sharp directivity. 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, although conventional sound input devices can collect sound by enhancing the sound from the sound source existing in the target direction, if both the sound source and other noise sources exist in the same target direction, There was a problem that it was not possible to separate the sound from the noise from the noise source.

  As a conventional means for solving the above problem, it is conceivable to perform signal processing such as noise removal. However, such signal processing causes a new problem that the amount of calculation becomes excessive.

  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 capable of enhancing and outputting sound from a sound source existing in a target area.

The invention according to claim 1 has a pair of microphone modules each having a sound collection area of a predetermined directivity angle, the pair of microphone modules are installed so that the sound collection areas intersect, and the pair of microphone modules Each of the microphone modules has a pair of directional microphones, each of the microphone modules having a predetermined directional angle. Receiving sound waves from the sound source that have a sound region and exist in the sound collection region, generate an observation signal based on the received sound waves, and a part of each sound collection region of the pair of directional microphones wherein an acoustic input device close to being placed so as to overlap include object area, from the sound source is placed at an intermediate position of the microphone module of the one pair And a non-directional microphone for generating a reference observation signal based on the reception by sound waves the reception waves, for each of the microphone module receives the observation signals from each of the pair of directional microphones, and the received 2 A phase difference correction unit that corrects a phase difference between the two observation signals by a phase difference between two observation signals when the sound source is present in a predetermined target direction, and a phase difference correction unit that has been corrected by the phase difference correction unit. A sound source position determination unit that determines whether or not the sound source exists in the target area using each observation signal; and when the sound source position determination unit determines that the sound source exists in the target area, A synthesized signal of the respective observation signals after the phase difference of the signal is corrected by the phase difference is amplified with a first amplification factor and output, while the sound source position determination unit performs the sound source Wherein if the target area is determined not to exist, and an output calculation unit for outputting the combined signal is amplified by the first amplification factor is smaller than the amplification factor, the phase difference correcting unit, the reference observation further receives a signal, the phase of the reference observation signal and the observed signal when either one of the phase difference of those said received reference observation signal and the received observation signal, the sound source is present in the target area Only the difference is corrected, and the power value of the observation signal for each microphone module after correction by the phase difference correction unit is set as an observation power value, and the reference observation signal after correction by the phase difference correction unit is corrected. the power value as a reference observation power value, the sound source position determination unit comprises a first range of relative ratio of one of the observed power value for the reference observation power value in hand microphone module is set in advance A first condition included in a range, a second condition in which a relative ratio of the other observed power value to the reference observed power value is included in a preset second range, and one of the reference observed power values in the other microphone module. The third condition in which the relative ratio of the observed power values is included in the preset third range, and the relative ratio of the other observed power value to the reference observed power value is included in the preset fourth range. If all four conditions are satisfied, it is determined that the sound source is present in the target area, while if any one of the first to fourth conditions is not satisfied, the sound source is not present in the target area. It is characterized by determining.

The invention of claim 2 has a pair of microphone modules each having a sound collection area of a predetermined directivity angle, the pair of microphone modules is installed so that the sound collection areas intersect, and the pair of microphone modules Each of the microphone modules has a pair of directional microphones, each of the microphone modules having a predetermined directional angle. Receiving sound waves from the sound source that have a sound region and exist in the sound collection region, generate an observation signal based on the received sound waves, and a part of each sound collection region of the pair of directional microphones wherein an acoustic input device close to being placed so as to overlap include object area, from the sound source is placed at an intermediate position of the microphone module of the one pair And a non-directional microphone for generating a reference observation signal based on the reception by sound waves the reception waves, for each of the microphone module receives the observation signals from each of the pair of directional microphones, and the received 2 A phase difference correction unit that corrects a phase difference between the two observation signals by a phase difference between two observation signals when the sound source is present in a predetermined target direction, and a phase difference correction unit that has been corrected by the phase difference correction unit. A sound source position determination unit that determines whether or not the sound source exists in the target area using each observation signal; and when the sound source position determination unit determines that the sound source exists in the target area, A synthesized signal of the respective observation signals after the phase difference of the signal is corrected by the phase difference is amplified with a first amplification factor and output, while the sound source position determination unit performs the sound source Wherein if the target area is determined not to exist, and an output calculation unit for outputting the combined signal is amplified by the first amplification factor is smaller than the amplification factor, the phase difference correcting unit, the received A discrete value of each observation signal is extracted at a predetermined time interval, the reference observation signal is further received , a discrete value of the reference observation signal is extracted at the predetermined time interval, and the sound source position determination unit is connected to each microphone module. Correlation function R _ij (i, j = 0, 1, 2, 3, 4) represented by Equation 4 is obtained using the discrete values x1 to x4 of the observed signal and the discrete value x0 of the reference observed signal for each. In the first microphone module, the first condition in which the relative ratio of the cross-correlation function R ₀₁ to the auto-correlation function R ₀₀ is included in a preset first range, the cross-correlation function R ₀ to the auto-correlation function R _{00 is The second condition in which} the relative ratio of 2 is included in the preset second range, and the relative ratio of the cross correlation function R _{03 to} the autocorrelation function R ₀₀ in the other microphone module is included in the preset third range. If the relative condition of the cross-correlation function R _{04 with} respect to the auto-correlation function R ₀₀ satisfies all the conditions of the fourth condition included in the preset fourth range, the sound source is placed in the target area. While it is determined that the sound source exists, if any one of the first to fourth conditions is not satisfied, it is determined that the sound source does not exist in the target area.

According to a third aspect of the invention, in the first or second aspect of the invention, when the sound source position determination unit satisfies any three conditions of the first to fourth conditions, the sound source region of the four directional microphones When it is determined that the sound source is present in a portion where three sound collection areas overlap and two conditions of the first to fourth conditions are satisfied, two sound collections of the sound collection areas of the four directional microphones When it is determined that the sound source is present in the overlapping area, and any one of the first to fourth conditions is satisfied, only one sound collection area is selected from the sound collection areas of the four directional microphones. It is determined that the sound source is present, and when none of the first to fourth conditions is satisfied, it is determined that the sound source is present in a region other than the sound collection region of the four directional microphones. .

According to a fourth aspect of the present invention, in the third aspect of the present invention, the output calculation unit includes the sound source in a portion where three sound collection regions of the four directional microphones are overlapped by the sound source position determination unit. If it is determined, the synthesized signal is amplified with a third amplification factor smaller than the first amplification factor and output, and the sound source position determination unit collects two of the sound collection regions of the four directional microphones. When it is determined that the sound source is present in a portion where sound regions overlap, the synthesized signal is amplified and output with a fourth amplification factor smaller than the third amplification factor, and four directivities are output by the sound source position determination unit. When it is determined that the sound source exists in only one sound collection region of the microphone sound collection regions, the synthesized signal is amplified and output with a fifth amplification factor smaller than the fourth amplification factor, Sound source When the position determination unit determines that the sound source is present in a region other than the sound collection region of the four directional microphones, the synthesized signal is amplified with a sixth amplification factor smaller than the fifth amplification factor. It is characterized by outputting.

The invention of claim 5 has a pair of sound generation regions each having a sound collection region with a predetermined directivity angle and receiving a sound wave from a sound source existing in the sound collection region and generating a reception signal based on the received sound wave. Each of the pair of microphone modules has a microphone module, and the pair of microphone modules is installed so that the respective sound collection areas cross each other, and the sound collection unit whose target area is the area where the sound collection areas overlap each other A sound source position determination unit that determines whether or not the sound source exists in the target area using the generated received signal, and the sound source position determination unit that determines that the sound source exists in the target area; A first amplification is performed on the combined signal of the two received signals after the phase difference between the two received signals is corrected by the phase difference between the two received signals when the sound source is present in the target region. rate On the other hand, when the sound source position determination unit determines that the sound source does not exist in the target area, the output is amplified and output with an amplification factor smaller than the first amplification factor. The sound source position determination unit determines whether or not the sound source exists in the vicinity of the target region when the sound source is determined not to exist in the target region, and the output calculation unit When the sound source position determination unit determines that the sound source is present in the vicinity of the target region, the gain of the continuous change characteristic monotonously decreases from the first gain as the distance from the target position increases. The synthesized signal is amplified and output.

A sixth aspect of the invention is characterized in that, in the invention of any one of the first to fifth aspects, the sound collection area of each of the microphone modules is variable.

The invention according to claim 7 is the invention according to any one of claims 1 to 5 , wherein a plurality of the sound collecting portions are arranged on the same straight line.

The invention according to claim 8 is the invention according to any one of claims 1 to 5 , characterized in that a plurality of the sound collecting portions are arranged in parallel.

The invention of claim 9 is the invention of any one of claims 1 to 5 , characterized in that a plurality of the sound collecting portions are arranged two-dimensionally.

The invention of claim 10 has a pair of microphone modules each having a sound collection area of a predetermined directivity angle, the pair of microphone modules are installed so that the sound collection areas intersect, and the pair of microphone modules Each of the microphone modules has a pair of directional microphones, each of the microphone modules having a predetermined directional angle. Receiving sound waves from the sound source that have a sound region and exist in the sound collection region, generate an observation signal based on the received sound waves, and a part of each sound collection region of the pair of directional microphones wherein an acoustic input device close to being placed so as to overlap include object area, or the sound source is placed at an intermediate position of the microphone module of the one pair And a non-directional microphone to generate the to reception of the sound wave reference observation signal based on sound waves the reception, for each of the microphone module receives the observation signals from each of the pair of directional microphones, and the received After the phase difference between the two observation signals is corrected by the phase difference correction unit that corrects the phase difference between the two observation signals when the sound source exists in a predetermined target direction, and after the phase difference correction unit corrects the phase difference A sound source position determination unit that determines whether or not the sound source exists in the target region using each of the observation signals, and when the sound source position determination unit determines that the sound source exists in the target region, The synthesized signal of each observation signal after the phase difference of the observation signal is corrected by the phase difference is amplified with a first amplification factor and output, while the sound source position determination unit If but determined not to exist in the target area, and an output calculation unit for outputting the combined signal is amplified by the first amplification factor is smaller than the amplification factor, the phase difference correcting unit, the reference further receives the observation signals, the reference observation signal and those 該観 measuring signal when either one of the phase difference between the reference observation signal the received and the received observation signals, sound source to the destination direction is present After correcting only the phase difference, the power value of the observation signal for each of the microphone modules after being corrected by the phase difference correction unit is the first to fourth observation power values, and after being corrected by the phase difference correction unit wherein a reference observation power value power value of the reference observation signal, the sound source position determination unit, any of the previous SL first to fourth observation power value is greater than the predetermined threshold, two observation power at each microphone module When the relative ratio of the values is equal to or greater than a predetermined first set value, the cross correlation function between the two observation signals in each microphone module is a predetermined second setting obtained from the autocorrelation function of each observation signal. When the condition that is greater than or equal to the value is satisfied, it is determined that the sound source exists in each of the target region and other regions other than the target region, and when the condition is not satisfied, the sound source does not exist in the target region. determining that, if the sound source to each microphone module is determined to present in each of the target region and the other region, at least one of the observed power values of the two observation power value for the previous Kimoto quasi observed power value when the ratio of the relative is included in a preset range, the sound source to at least one of the sound collecting area of the directional microphone of the one pair And judging to be present.

According to an eleventh aspect of the present invention, in the invention according to the tenth aspect , the output calculation unit is configured to add the sound source position determination unit to at least one of the sound collection regions of each directional microphone and the target region among the other regions. When it is determined that a sound source is present, an observation signal of a directional microphone in which the sound source does not exist in the sound collection region in the other region is amplified by the first amplification factor and output.

The invention of claim 12 is the invention of claim 11 , further comprising driving means for inclining a directivity axis of the first to fourth directional microphones, wherein the sound source position determination unit is configured such that the sound source is the sound source in each microphone module. and the target region, wherein among other areas if it is determined to be present in either preparative sound collecting area of the directional microphone of the one pair, the one pair of observations power value of the relative ratio of the first set value controlling said drive means satisfies the conditions to be less than, the output calculation section determines that the sound source to the sound collecting area of the directional microphone of the one pair by the sound source position determination unit after the driving of the drive means is present If it is, while outputting the combined signal of the observation signals of the one pair after driving of said driving means is amplified by the first amplification factor, the sound source before by the sound source position determination unit If it is determined not to exist in the target area, characterized in that amplifies and outputs the combined signal with the first amplification factor is smaller than the second amplification factor.

The invention of claim 13 has a pair of microphone modules each having a sound collection area of a predetermined directivity angle, the pair of microphone modules are installed so that the sound collection areas intersect, and the pair of microphone modules Each of the microphone modules has a pair of directional microphones, each of the microphone modules having a predetermined directional angle. Receiving sound waves from the sound source that have a sound region and exist in the sound collection region, generate an observation signal based on the received sound waves, and a part of each sound collection region of the pair of directional microphones wherein an acoustic input device close to being placed so as to overlap include object area, or the sound source is placed at an intermediate position of the microphone module of the one pair And a non-directional microphone to generate the to reception of the sound wave reference observation signal based on sound waves the reception, for each of the microphone module receives the observation signals from each of the pair of directional microphones, and the received After the phase difference between the two observation signals is corrected by the phase difference correction unit that corrects the phase difference between the two observation signals when the sound source exists in a predetermined target direction, and after the phase difference correction unit corrects the phase difference A sound source position determination unit that determines whether or not the sound source exists in the target region using each of the observation signals, and when the sound source position determination unit determines that the sound source exists in the target region, The synthesized signal of each observation signal after the phase difference of the observation signal is corrected by the phase difference is amplified with a first amplification factor and output, while the sound source position determination unit If but determined not to exist in the target area, and an output calculation unit for outputting the combined signal is amplified by the first amplification factor is smaller than the amplification factor, the phase difference correcting unit, the reference further receives the observation signal, a reference observation signal and those 該観 measuring signal when either one of the phase difference between the reference observation signal the received and the received observation signals, sound source to the destination direction is present phase Only the difference is corrected, and the power value of the observation signal for each of the microphone modules after being corrected by the phase difference correction unit is set as the first to fourth observation powers, and after the correction by the phase difference correction unit, the power value of the reference observation signal and a reference observation power value, the sound source position determination unit, in a case before Symbol both is greater than a predetermined threshold value of the first to fourth observation power value, the two at each microphone module When the cross-correlation function of the observation signal satisfies a condition that is equal to or greater than a predetermined set value obtained from the auto-correlation function of each observation signal, the sound source is in each of the target region and other regions other than the target region. while determining the present, when does not satisfy the condition, determines that the sound source is not present in the target area, it is determined that the sound source for each of the microphone module is present in each of the object region and the other region If, before when the relative ratio of at least one of the observed power values of the two observation power values for Kimoto quasi observed power value is included in a predetermined range, each of the sound collection region of the directional microphone of the one pair It is determined that the sound source exists.

The invention of claim 14 is the invention of claim 13 , further comprising driving means for inclining a directional axis of the first to fourth directional microphones, wherein the sound source position determination unit is configured such that in each microphone module, the sound source includes the sound source. and the target region, if it is determined that also exists in any of the sound collecting area of the directional microphone of the one pair of the other areas, the two sound sources each microphone module from the target area of the other regions 2 The driving means is controlled until a relative ratio of the two observation power values is less than a predetermined set value when the directivity angle is more than one half of the maximum value of the directivity angles of the two directional microphones. the output calculation unit was determined to be the sound source to the sound collecting area of the directional microphone of the one pair by the sound source position determination unit after the driving of the drive means is present If, while that amplifies and outputs in the first amplification factor a composite signal of the observation signal of said one pair after the driving of said driving means, when the sound source by the sound source position determination unit is not present in the target area If it is determined, the synthesized signal is amplified by a second amplification factor smaller than the first amplification factor and output.

According to the first aspect of the present invention, a pair of microphone modules are installed so that their sound collection areas intersect, a specific target area including not only the direction but also the distance is set, and the sound source exists in the target area. In this case, the sound from the sound source existing in the target area can be emphasized and output by amplifying and outputting with a larger amplification factor than when the sound source does not exist in the target area.
According to the first aspect of the present invention, since the target area is set using four directional microphones, the distance between the two directional microphones can be reduced in each microphone module. It can be made smaller than a microphone or a microphone array, and it is not necessary to extremely narrow the directivity angle of the microphone.
Furthermore, according to the invention of claim 1, by the omnidirectional microphones placed at the center of a pair of microphones module, used each observation power value for the reference observation power value from the non-directional microphone, sound source It can be accurately determined whether or not the target area exists.

According to the invention of claim 2, a pair of microphone modules are installed so that their sound collection areas intersect, a specific target area including not only a direction but also a distance is set, and a sound source exists in the target area In this case, the sound from the sound source existing in the target area can be emphasized and output by amplifying and outputting with a larger amplification factor than when the sound source does not exist in the target area.
According to the second aspect of the present invention, since the target area is set using four directional microphones, the distance between the two directional microphones can be reduced in each microphone module. It can be made smaller than a microphone or a microphone array, and it is not necessary to extremely narrow the directivity angle of the microphone.
Furthermore, according to the invention of claim 2 , by using the autocorrelation function of the reference observation signal or the cross-correlation function between the reference observation signal and each observation signal , the influence of uncorrelated noise is reduced and a high S / N ratio is obtained. And the accuracy of determining whether or not the sound source exists in the target area can be increased.

According to the invention of claim 3 , even if the sound source does not exist in the target area, it can be determined how far away the sound source is from the target area.

According to the invention of claim 4 , when the sound source does not exist in the target area, the larger the number of overlapping sound collecting areas of the plurality of directional microphones, the larger the amplification factor can be given, and the magnitude of the output signal. Can be changed.

According to the invention of claim 5, a pair of microphone modules are installed so that the respective sound collection areas intersect with each other, a specific target area including not only the direction but also the distance is set, and the sound source exists in the target area. In this case, the sound from the sound source existing in the target area can be emphasized and output by amplifying and outputting with a larger amplification factor than when the sound source does not exist in the target area.
Further, according to the invention of claim 5, it is possible to gain for amplifying the composite signal is prevented from becoming discontinuous by the location of the sound source, (power value of the output signal) as a result, the output signal Can always be a continuous value.

According to the invention of claim 6 , while changing the sound collection area of the microphone module, for example, by continuously collecting sound from adjacent areas in time, the aspect ratio of the target area is increased and the target area is expanded. Can be planned.

According to the invention of claim 7 , by arranging a plurality of sound collecting portions on the same straight line, it is possible to enlarge the target area by increasing the aspect ratio of the target area.

According to the invention of claim 8 , by arranging a plurality of sound collecting portions in parallel, not only the aspect ratio of the target region is increased, but also the target region is enlarged in the direction perpendicular to the sound collecting portion. Can do.

According to the ninth aspect of the present invention, for example, by providing the microphone modules so as to be arranged in a circle having a diameter between the microphone modules of the sound collecting unit, the sound collecting unit collects not only from the front region but also from the side region. Can make sound.

According to the invention of claim 10, a pair of microphone modules are installed so that their sound collecting areas intersect, a specific target area including not only the direction but also the distance is set, and the sound source exists in the target area. In this case, the sound from the sound source existing in the target area can be emphasized and output by amplifying and outputting with a larger amplification factor than when the sound source does not exist in the target area.
According to the invention of claim 10, since the target area is set using four directional microphones, the interval between the two directional microphones can be reduced in each microphone module. It can be made smaller than a microphone or a microphone array, and it is not necessary to extremely narrow the directivity angle of the microphone.
Further, according to the invention of claim 10 , there is one sound source in a region where the sound collection regions of the first to fourth directional microphones overlap, and within any one of the sound collection regions of the first to fourth directional microphones. It can be determined that there is another sound source.

According to the invention of claim 11 , the signal from the sound source in the target area can be amplified and output.

According to the twelfth aspect of the present invention, it is possible to amplify and output a signal from the sound source in the target area.

According to the invention of claim 13, a pair of microphone modules are installed so that the respective sound collection areas intersect, a specific target area including not only the direction but also the distance is set, and the sound source exists in the target area. In this case, the sound from the sound source existing in the target area can be emphasized and output by amplifying and outputting with a larger amplification factor than when the sound source does not exist in the target area.
According to the invention of claim 13, by setting the target area using four directional microphones, the distance between the two directional microphones can be reduced in each microphone module. It can be made smaller than a microphone or a microphone array, and it is not necessary to extremely narrow the directivity angle of the microphone.
Furthermore, according to according to the invention of claim 13, one of the sound source in the region where the sound collecting areas of the first to fourth directional microphone overlap exists, either collected in the area of the first to fourth directional microphone It can be determined that there is another sound source.

According to the fourteenth aspect of the present invention, it is possible to emphasize and output a signal from the sound source in the target area.

(Embodiment 1)
First, the structure of the acoustic input device of Embodiment 1 is demonstrated using FIG. 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 (received wave) that is described later based on the sound collected by the sound collecting unit 1. A signal processing unit 2 that calculates an output signal y (k, m) using signals xa (t) and xb (t).

The sound collection unit 1 includes a pair of microphone modules ( hereinafter referred to as “ one pair ”) each having a sound collection region with a predetermined directivity angle α1, α2 (see FIG. 2) (the first microphone module 10 and the second microphone module 2). Microphone module 11). The first microphone module 10 and the second microphone module 11 are very sharp in directivity such as a super-directional microphone, a microphone array, and a beam former, for example. As shown in FIG. The intersection of the central axes A1 and A2 of each sound collection area is set as the target position B, and the area where the sound collection areas overlap is set as the target area C.

  As shown in FIG. 1, each of the microphone modules 10 and 11 installed as described above receives sound waves from a sound source (not shown) existing in the sound collection region, and is based on the received sound waves. Observation signals xa (t) and xb (t) that are electrical signals are generated. The first observation signal xa (t) is output from the first microphone module 10 to the signal processing unit 2, and the second observation signal xb (t) is output from the second microphone module 11 to the signal processing unit 2.

  Although the first microphone module 10 and the second microphone module 11 of the present embodiment have the same sensitivity, even if the sensitivity is different, the observation signal based on the received sound wave is used as the sensitivity coefficient. What is necessary is just to use what was correct | amended by new observation signal xa (t), xb (t). Specifically, the sensitivity coefficient of the first microphone module 10 is ma, and the sensitivity coefficient of the second microphone module 11 is mb (ma ≠ mb) (observation based on the sound wave received by the first microphone module 10) (Signal × ma) is the first observation signal xa (t) transmitted to the signal processing unit 2, and (observation signal × mb based on the sound wave received by the second microphone module 11) is the signal processing unit 2 The second observation signal xb (t) transmitted to At this time, the sensitivity coefficients ma and mb are set so as to satisfy ma: mb = √ (Pxb): √ (Pxa) using Pxa and Pxb 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 xa (t) and xb (t) and receives the discrete value xa (k, m) of the first observation signal and the second observation signal. The phase difference correction unit 20 for correcting the phase difference of the discrete values xb (k, m) of the first and second values based on the discrete values xa (k, m) and xb (k, m) of the first and second observation signals. The sound source position determination unit 21 that determines whether or not the sound source exists in the target region using the observed power values Pxa (k) and Pxb (k) of 2, and the output signal according to the determination result of the sound source position 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 xa (t) from the first microphone module 10, divides the received first observation signal xa (t) into frames having a frame length L, Every time, the discrete value xa (k, m) of the first observation signal is extracted at a predetermined time interval Δt. Similarly, the second observation signal xb (t) is received from the second microphone module 11, and the second observation signal xb (t) is divided into frames having a frame length L, and the second observation signal xb (t) is divided into frames for each frame. A discrete value xb (k, m) of the observation signal is extracted at a predetermined time interval Δt. Note that the discrete values xa (k, m) and xb (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 xa (k, m) and xb (k, m) of the first and second observation signals and the extracted discrete values xa (k, m) of the first observation signal. The phase difference between the discrete values xb (k, m) of the second observation signal is the phase difference between the first observation signal xa (t) and the second observation signal xb (t) when a sound source is present in the target region. Only correct.

  For example, when the target position that is the intersection of the central axes of the sound collection areas in the target area is a direction inclined by an angle φ from the central axes of the first microphone module 10 and the second microphone module 11, Phase difference 2dsinφ (2d: distance between the first microphone module 10 and the second microphone module 11) between the first observation signal xa (t) and the second observation signal xb (t) when a sound source is present at Will occur. Assuming that the speed of sound is c, a time lag occurs by the time τ = 2dsinφ / c. Therefore, the discrete value xb (k, m) of the second observation signal is delayed by time τ, and the new discrete value xb ′ (k, m) = xb (k, m−τ / By setting Δt), the phase difference between the discrete value xa (k, m) of the first observation signal and the discrete value xb (k, m) of the second observation signal can be corrected.

  In the present embodiment, as shown in FIG. 2, since the target position is the direction of the central axis D of the first microphone module 10 and the second microphone module 11, there is a case where a sound source exists at the target position. Since no phase difference occurs between the first observation signal xa (t) and the second observation signal xb (t), xb ′ (k, m) = xa (k, m).

  The discrete values xa (k, m) and xb ′ (k, m) of the first and second observation signals corrected by the phase difference correction unit 20 are output to the sound source position determination unit 21.

  The sound source position determination unit 21 shown in FIG. 1 calculates, for each frame, an average value for a predetermined time (frame length) of the square sum of the discrete values xa (k, m) of the first observation signal as shown in Equation 5. The first observed power value Pxa (k) is calculated and the average value of the sum of squares of the discrete values xb ′ (k, m) of the second observed signal for a predetermined time is calculated for each frame. The observed power value Pxb (k) is assumed. In Equation 5, i = a, b.

  The sound source position determination unit 21 that has calculated the first and second observed power values Pxa (k) and Pxb (k) uses the first and second observed power values Pxa (k) and Pxb (k) to determine whether the sound source is It is determined whether or not the target area exists. Specifically, the sound source position determination unit 21 satisfies the condition that both the first and second observation power values Pxa (k) and Pxb (k) are larger than a predetermined threshold value Pth, and the sound source is set as the target region. It is determined that it exists. On the other hand, if the above condition is not satisfied, the sound source position determination unit 21 determines that the sound source does not exist in the target area.

  The output calculation unit 22 receives the first observation signal xa (t) from the first microphone module 10 and the second observation signal xb (t) from the second microphone module 11, and receives a digital signal processor (hereinafter “ DSP "), the discrete values xa (k, m) and xb (k, m) of the first and second observation signals are obtained from the first and second observation signals xa (t) and xb (t). The discrete value xb (k, m) of the second observation signal is delayed by the time τ, and the new discrete value xb ′ (k, m) = xb (k, m−τ / Δt), and the sum (xa (k, m) + xb ′ (k, m)) of the discrete values xa (k, m) and xb ′ (k, m) of the first and second observation signals is obtained. In the present embodiment, since no delay occurs, xb ′ (k, m) = xb (k, m).

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

  Next, the operation of the acoustic input device of this embodiment will be described. First, when the first and second microphone modules 10 and 11 of the sound collection unit 1 receive sound waves from the sound source, the first and second observation signals xa (t) and xb (t) are signals from the sound collection unit 1. It is transmitted to the processing unit 2. In the signal processing unit 2, the phase difference correction unit 20 extracts the discrete values xa (k, m) and xb (k, m) of the first and second observation signals. Thereafter, the phase difference correction unit 20 has a sound source in the target area (for example, the target position that is the intersection of the central axes of the sound collection areas) with respect to the discrete value xb (k, m) of the second observation signal. This is shifted by the phase difference of the case, and this is set as the discrete value xb ′ (k, m) of the second observation signal.

  The sound source position determination unit 21 calculates the first and second observation power values Pxa (k) and Pxb (k) for each frame. Thereafter, the sound source position determination unit 21 examines whether or not the condition that both the first and second observation power values Pxa (k) and Pxb (k) are larger than the threshold value Pth is satisfied. If the above condition is not satisfied, it is determined that the sound source does not exist in the target area. On the other hand, when the above condition is satisfied, it is determined that the sound source exists in the target area.

  When it is determined that the sound source exists in the target area, the output calculation unit 22 outputs G1 (xa (k, m) + xb ′ (k, m)) as the output signal y (k, m), and the sound source is the target. If it is determined that the region does not exist, G2 (xa (k, m) + xb ′ (k, m)) (G2 <G1) is output as the output signal y (k, m).

  From the above, the sound collection and sound source separation method using the conventional super-directional microphone can only emphasize the sound from a specific target direction, but the sound input device of the present embodiment has a specific direction and a specific distance. By limiting the target area in (1), the sound from the sound source existing in the target area can be emphasized. Thereby, noise from an area other than the target area can be suppressed, and sound from the sound source can be collected with a high S / N ratio.

  As described above, according to the present embodiment, a pair of microphone modules (the first microphone module 10 and the second microphone module 11) are installed so that the respective sound collection areas intersect, and not only the direction but also the distance. By setting a specific target area to be included, and when the sound source is present in the target area, it is amplified with a larger amplification rate than when the sound source is not present in the target area, and output from the sound source existing in the target area. Can be emphasized and output.

  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 xa (t) A new sum (xa (t) + xb ′ (t)) of the second observation signal xb ′ (t) = xb (t−τ) obtained by delaying the second observation signal xb (t) by the time τ. May be output. That is, when it is determined that the sound source exists in the target region, the output calculation unit 22 outputs the output signal y (t) = G1 (xa (t) + xb ′ (t)), and the sound source exists in the target region. When it is determined not to output, the output signal y (t) = G2 (xa (t) + xb ′ (t)) (G2 <G1) is output.

(Embodiment 2)
In the acoustic input device according to the first embodiment, each of the microphone modules 10 and 11 is a super-directional microphone. In such a case, in order to set the target area C at a position away from the sound collection unit 1, It is necessary to extremely narrow the directivity angle of the microphone modules 10 and 11 or widen the distance between the microphone modules 10 and 11.

  Therefore, the acoustic input device according to the second embodiment will be described assuming that the target area C can be easily set at a position away from the sound collection unit 1. As shown in FIG. 3, the acoustic input device according to the present embodiment includes a pair of directional microphones 30 to 33 each having a sound collection region having predetermined directivity angles α1 to α4 as the microphone modules 10a and 11a. This is different from the sound input device according to the first embodiment (see FIG. 1). 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. 4B, the first directional microphone 30 and the second directional microphone 31 are installed close to each other as the first microphone module 10a, and the third directional microphone 32 and the fourth directional microphone 31 are arranged. Directivity microphones 33 are installed in close proximity to each other as the second microphone module 11a.

  As shown in FIG. 3, each of the first to fourth directional microphones 30 to 33 installed as described above receives a sound wave from a sound source, and an observation signal x1 (t) based on the received sound wave. ~ X4 (t) is generated. The first observation signal x1 (t) is transmitted from the first directional microphone 30 to the signal processing unit 2a, and the second observation signal x2 (t) is transmitted from the second directional microphone 31 to the signal processing unit 2a. Observation signal x3 (t) is output from the third directional microphone 32 to the signal processing unit 2a, and the fourth observation signal x4 (t) is output from the fourth directional microphone 33 to the signal processing unit 2a.

  By the way, the characteristics of the first to fourth directional microphones 30 to 33 are, as shown in FIG. 5, the first to fourth observed power values Px1 (k) described later at the position of the angle φ from the central axis A1 of the directivity. ) To Px4 (k) are high and almost constant when 0 ° ≦ | φ | <φ1, decrease rapidly as the angle φ increases when φ1 ≦ | φ | <φ2, and decrease substantially when φ2 <| φ | It is constant. The angle θ of the area where the sound collection areas overlap is 0 ° <θ <min (α3, α4).

  The first to fourth directional microphones 30 to 33 have the same sensitivity. However, even if the sensitivities are different, the one obtained by correcting the observation signal based on the received sound wave with the sensitivity coefficient is used. New observation signals x1 (t) to x4 (t) may be used. Specifically, when the sensitivity coefficient of the first directional microphone 30 is m1 and the sensitivity coefficient of the second directional microphone 31 is m2 (m1 ≠ m2), (the first directional microphone 30 receives the wave). (Observation signal xm1) based on the sound wave received as the first observation signal x1 (t) transmitted to the signal processing unit 2a (observation signal xm2 based on the sound wave received by the second directional microphone 31) May be the second observation signal x2 (t) transmitted to the signal processing unit 2a. The same applies to the third directional microphone 32 and the third directional microphone 33. At this time, the sensitivity coefficients m1 and m2 are set to satisfy m1: m2 = √ (Px2): √ (Px1) using Px1 and Px2 described later, and the sensitivity coefficients m3 and m4 are set as Px3 and Px3 described later. Using Px4, it is set so as to satisfy m3: m4 = √ (Px4): √ (Px3). The same applies to the following description.

  The phase difference correction unit 20a of the present embodiment receives the first and second observation signals x1 (t) and x2 (t) from the first and second directional microphones 30 and 31 in the first microphone module 10a. Each observation signal x1 (t), x2 (t) is divided into frames of frame length L, and the discrete values x1 (k, m), x2 (k, m) of the first and second observation signals are divided for each frame. Extraction is performed at a predetermined time interval Δt. Similarly, the second microphone module 11a receives the third and fourth observation signals x3 (t) and x4 (t) from the third and fourth directional microphones 32 and 33, and receives each observation signal x3 (t), x4 (t) is divided into frames having a frame length L, and discrete values x3 (k, m) and x4 (k, m) of the third and fourth observation signals are extracted at predetermined time intervals Δt for each frame. The discrete value xi (k, m) (i = 1, 2, 3, 4) of each observation signal means the mth discrete value in the kth frame.

  The phase difference correction unit 20a that has extracted the discrete values x1 (k, m) to x4 (k, m) of the first to fourth observation signals extracts the discrete values x1 (k, m) of the extracted first observation signal. And the phase difference between the discrete values x2 (k, m) of the second observation signal, the first observation signal x1 (t) and the second observation signal x2 (when the sound source exists in a predetermined target direction) Only the phase difference t) is corrected. Similarly, the phase difference correction unit 20a determines in advance the phase difference between the discrete value x1 (k, m) of the extracted first observation signal and the discrete value x3 (k, m) of the third observation signal. The phase difference between the first observation signal x1 (t) and the third observation signal x3 (t) when a sound source is present in the target direction is corrected, and the discrete value x1 (k , M) and the fourth observation signal, the phase difference between the discrete values x4 (k, m) of the fourth observation signal is the same as the first observation signal x1 (t) and the fourth observation when the sound source exists in a predetermined target direction. Only the phase difference of the signal x4 (t) is corrected.

  For example, when the target direction is a direction inclined by an angle φ from the central axis A1 of the first directional microphone 30 and the second directional microphone 31, when the sound source exists in the target direction, the first microphone 10 and Since the second microphone 11 is installed in close proximity, the sound waves from the sound source are incident substantially in parallel. Therefore, a phase difference 2dsinφ (2d: distance between the first directional microphone 30 and the second directional microphone 31) is generated between the first observation signal x1 (t) and the second observation signal x2 (t). . Assuming that the speed of sound is c, a time lag occurs by the time τ = 2dsinφ / c. From the above, 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) = x2 (k, m−τ) of the second observation signal. / 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. The case of the third directional microphone 32 and the fourth directional microphone 33 is the same as the case of the first directional microphone 30 and the second directional microphone 31.

  In the present embodiment, as shown in FIG. 4B, when the target direction is in the direction of the central axis E of the first directional microphone 30 and the second directional microphone 31, the sound source S1 is in the target direction. Since there is no phase difference between the first observation signal x1 (t) and the second observation signal x2 (t) when x is present, x2 ′ (k, m) = x2 (k, m). The same applies to the third directional microphone 32 and the fourth directional microphone 33.

  The discrete values x1 (k, m), x2 '(k, m), x3 (k, m), and x4' (k, m) of the first to fourth observation signals corrected by the phase difference correction unit 20a are sound sources. It is output to the position determination part 21a.

  The sound source position determination unit 21a illustrated in FIG. 3 calculates, for each frame, an average value for a predetermined time (frame length L) of the sum of squares of the discrete value x1 (k, m) of the first observation signal as shown in Equation 6. Then, the first observation power value Px1 (k) is set, and the average value of the second sum of squares of the discrete values x2 ′ (k, m) of the second observation signal is calculated for each frame to obtain the second observation. In addition to the power value Px2 (k), an average value of the sum of squares of the discrete value x3 (k, m) of the third observation signal for a predetermined time is calculated for each frame, and the third observation power value Px3 (k ) And the average value of the square sum of the discrete values x4 ′ (k, m) of the fourth observation signal for a predetermined time is calculated for each frame to be the fourth observation power value Px4 (k). In Equation 6, i = 1, 2, 3, and 4.

  The sound source position determination unit 21a that has calculated the first to fourth observation power values Px1 (k) to Px4 (k) uses the first to fourth observation power values Px1 (k) to Px4 (k), It is determined whether or not the target area exists.

  Here, as shown in FIG. 4, in the region where the sound collection region of the first directional microphone 30 and the sound collection region of the second directional microphone 31 overlap, the first observation power value Px1 (k) The relative ratio of the observed power values Px2 (k) of 2 is small, and the relative ratio between the first observed power value Px1 (k) and the second observed power value Px2 (k) is large in a region other than the above. The same applies to the third directional microphone 32 and the fourth directional microphone 33.

Therefore, the sound source position determination unit 21a illustrated in FIG. 3 has all of the first to fourth observation power values Px1 (k) to Px4 (k) larger than the predetermined threshold value Pth, and the second microphone module 10a performs the second operation. Relative ratio of the first observed power value Px1 (k) to the observed power value Px2 (k) | 10log ₁₀ (Px1 (k) / Px2 (k)) | (dB) is 0 or more and a predetermined set value ε (dB) Less than (0 ≦ | ₁₀ log ₁₀ (Px1 (k) / Px2 (k)) | <ε) (first condition), the sound collection region and the second directivity of the first directional microphone 30 are satisfied. It is determined that the sound source exists in a region where the sound collection regions of the directional microphone 31 overlap, and the phase of the third observation power value Px3 (k) with respect to the fourth observation power value Px4 (k) in the second microphone module 11a. The ratio _{| 10log 10 (Px3 (k)} / Px4 (k)) | (dB) is 0 or a predetermined set value ε less than _{(dB) (0 ≦ | 10log} 10 (Px3 (k) / Px4 (k)) | < If the condition (ε condition) (second condition) is satisfied, it is determined that the sound source exists in a region where the sound collection region of the third directional microphone 32 and the sound collection region of the fourth directional microphone 33 overlap. Then, the sound source position determination unit 21a determines that the sound source exists in the target area when both the first and second conditions are satisfied, and if the sound source does not satisfy any one of the first and second conditions, the sound source is determined as the target area. Is determined not to exist.

  The output calculation unit 22a receives the first to fourth observation signals x1 (t) to x4 (t) from the first to fourth directional microphones 30 to 33 of the first and second microphone modules 10a and 11a, and the DSP Are used to obtain discrete values x1 (k, m) to x4 (k, m) of the first to fourth observation signals from the first to fourth observation signals x1 (t) to x4 (t), The discrete values x2 (k, m) and x4 (k, m) of the fourth observation signal are delayed by the time τ, and the new discrete values x2 ′ (k, m) = x2 ( k, m−τ / Δt), x4 ′ (k, m) = x4 (k, m−τ / Δt), and discrete values x1 (k, m), x2 ′ (k , M), x3 (k, m), x4 ′ (k, m) (x1 (k, m) + x2 ′ (k, m) + x3 (k, m) + x4 ′ (k, m))) . In this embodiment, since no delay occurs, x2 '(k, m) = x2 (k, m), x4' (k, m) = x4 (k, m).

  When the sound source position determination unit 21a determines that the sound source exists in the target area, the output calculation unit 22a combines the signal (x1 (k, m) + x2 ′ (k, m) + x3 (k, m) + x4 ′ ( k, m)) is amplified by the first amplification factor G1, and output as an output signal y (k, m). On the other hand, when the sound source position determination unit 21a determines that the sound source does not exist in the target region, the output calculation unit 22a outputs the composite signal (x1 (k, m) + x2 ′ (k, m) + x3 (k, m). + X4 ′ (k, m)) is amplified with a second amplification factor G2 smaller than the first amplification factor G1, and output as an output signal y (k, m).

  As described above, according to the present embodiment, by setting the target area using the four directional microphones 30 to 33, the first directional microphone 30 and the second directional characteristic are set in each of the microphone modules 10a and 11a. Since the distance between the microphones 31 and the distance between the third directional microphone 32 and the fourth directional microphone 33 can be reduced, the size can be reduced compared to a super-directional microphone or a microphone array, and the directivity angle of the microphone can be reduced. It is no longer necessary to squeeze extremely.

  Furthermore, it is possible to accurately determine whether or not a sound source exists in the target area using each of the observed power values Px1 (k) to Px4 (k).

  The directivity angle α of the first to fourth directional microphones 30 to 33 according to the second embodiment may have various directivity angles. Specifically, it is not limited to the one shown in FIG. 4, but as shown in FIG. 6 (with a directivity angle of 90 °) or as shown in FIG. 7 (with a directivity angle of 180 °). But you can. The same applies to the following embodiments.

  As a modification of the second embodiment, the output calculation unit 22a illustrated in FIG. 3 does not output the digital signal output signal y (k, m), but the first and third observation signals x1 (t), x3 (t) and new second and fourth observation signals x2 ′ (t) = x2 (t−τ) obtained by delaying the second and fourth observation signals x2 (t) and x4 (t) by time τ , X4 ′ (t) = x4 (t−τ) (x1 (t) + x2 ′ (t) + x3 (t) + x4 ′ (t)) may be amplified and output. That is, when it is determined that the sound source exists in the target area, the output calculation unit 22a outputs the output signal y (t) = G1 (x1 (t) + x2 ′ (t) + x3 (t) + x4 ′ (t)). If it is determined that the sound source does not exist in the target area, the output signal y (t) = G2 (x1 (t) + x2 ′ (t) + x3 (t) + x4 ′ (t)) (G2 <G1) is obtained. Output.

(Embodiment 3)
In the acoustic input device according to the third embodiment, the sound source position determination unit 21a illustrated in FIG. 3 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. Implementation in that the cross-correlation function R ₃₄ (Equation 7) of the discrete values x3 (k, m) and x4 ′ (k, m) of the (Equation 7) and the third and fourth observation signals is calculated for each frame. This is different from the acoustic input device according to mode 2. The correlation function R _{ij in Equation} 7 is an autocorrelation function when i = j, and a cross-correlation function when i ≠ j. In addition, about the component similar to Embodiment 2, the same code | symbol is attached | subjected and description is abbreviate | omitted.

As shown in FIG. 8, the cross-correlation functions R ₁₂ and R ₃₄ are areas (−θ / 2 <φ <θ / 2) where the sound collection areas of the first directional microphone 30 and the second directional microphone 31 overlap. ), And an area where the sound collection areas of the third directional microphone 32 and the fourth directional microphone 33 overlap (−θ / 2 <φ <θ / 2), and a small value in other areas. It becomes. Therefore, when the sound source position determination unit 21a satisfies the condition (first condition) where cross-correlation function R ₁₂ > threshold Rth, the sound collection regions of the first directional microphone 30 and the second directional microphone 31 overlap. When it is determined that a sound source is present in the area and the condition (second condition) satisfying the cross-correlation function R ₃₄ > threshold Rth is satisfied, the sound collection regions of the third directional microphone 32 and the fourth directional microphone 33 overlap. It is determined that there is a sound source in the area. When the first and second conditions are satisfied, the sound source position determination unit 21a determines that the sound source is present in the target area. On the other hand, when any one of the first and second conditions is not satisfied, the sound source is not included in the target area. Judge that it does not exist.

For the determination of the threshold value Rth, the autocorrelation function R ₁₁ of the discrete value x1 (k, m) of the first observation signal, the autocorrelation function R ₂₂ of the discrete value x2 (k, m) of the second observation signal, discrete values of the third observation signal x3 (k, m) of the autocorrelation function _{R 33,} discrete values x4 (k, m) of the fourth observation signal using an autocorrelation function _{R 44} in. Since the autocorrelation functions R ₁₁ , R ₂₂ , R ₃₃ , and R ₄₄ 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 the present embodiment, the cross-correlation function R ₁₂ between the discrete value x1 (k, m) of the first observation signal and the discrete value x2 ′ (k, m) of the second observation signal, the third observation. discrete value x3 (k, m) of the signal discrete value x4 '(k, m) of the fourth observation signal by evaluating the cross-correlation function R ₃₄ of accuracy whether the sound source is present in the target area Can be judged well.

(Embodiment 4)
As shown in FIG. 9, the acoustic input device of the fourth embodiment includes a first microphone module 10a (first and second directional microphones 30 and 31) and a second microphone module 11a (first microphone) in the sound collecting unit 1b. 3 and 4 having a non-directional microphone 12 installed at an intermediate position between the directional microphones 32 and 33) for receiving a sound wave from a sound source and generating a reference observation signal that is an electric signal based on the received sound wave. Thus, it is different from the sound input device of the second embodiment (see FIG. 3). In addition, about the component similar to Embodiment 2, 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 the first to fourth directional microphones 30 to 33. However, even if the sensitivity is different, it is based on the received sound wave. 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 2b. 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.

  As shown in FIG. 9, the first directional microphone 30 and the second directional microphone 31 are installed close to each other so that a part of each sound collection region overlaps with the target region. Similarly, the third directional microphone 32 and the fourth directional microphone 33 are also installed close to each other such that a part of each sound collection region overlaps with the target region.

  In the signal processing unit 2b of the present embodiment, as shown in FIG. 10, the phase difference correction unit 20b receives the reference observation signal x0 (t) from the omnidirectional microphone 12, and receives the received reference observation signal x0 (t). Is extracted at a predetermined time interval Δt, and the extracted discrete value x0 (k, m) of the reference observation signal is an intersection of the central axes of the sound collection regions in the target region. The phase difference between the reference observation signal x0 (t) and the first observation signal x1 (t) when the sound source is present at the target position is shifted.

  Further, the sound source position determination unit 21b 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 20b, and performs 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 position determination unit 21b having calculated the reference observation power value Px0 (k) in the first microphone module 10a has a relative ratio (Px1 (1) of the first observation power value Px1 (k) to the reference observation power value Px0 (k). k) / Px0 (k)) is included in a preset first range, the relative ratio (Px2 (k) of the second observed power value Px2 (k) to the reference observed power value Px0 (k) ) / Px0 (k)) is included in the second range set in advance, the third observation power value Px3 (k) relative to the reference observation power value Px0 (k) in the second microphone module 11a. The third condition in which the relative ratio (Px3 (k) / Px0 (k)) is included in the preset third range, the phase of the fourth observed power value Px4 (k) with respect to the reference observed power value Px0 (k) If the ratio (Px4 (k) / Px0 (k)) all satisfy the fourth condition included in the fourth preset range, it is determined that the sound source is present in the target area. On the other hand, when any one of the first to fourth conditions is not satisfied, the sound source position determination unit 21b determines that the sound source does not exist in the target area.

  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). The third range of the present embodiment is also a range greater than the initially set threshold value δ and equal to or less than 1 (δ <Px3 (k) / Px0 (k) ≦ 1). The fourth range of the present embodiment is also a range greater than the initially set threshold value δ and 1 or less (δ <Px4 (k) / Px0 (k) ≦ 1).

  As described above, according to the present embodiment, the omnidirectional microphone 12 is installed at the center position of the pair of microphone modules 10a and 11a, and the observed power values Px1 with respect to the reference observed power value Px0 (k) of the omnidirectional microphone 12 are set. By using (k) to Px4 (k), it can be accurately determined whether or not the sound source exists in the target area.

(Embodiment 5)
In the acoustic input device according to the fifth embodiment, the sound source position determination unit 21b illustrated in FIG. 10 includes the first to fourth observation signals x1 (k, m) to x4 (k, m) and the reference observation signal x0 (k, m). Is used to obtain a correlation function R _ij (i, j = 0, 1, 2, 3, 4) represented by Equation 8, and using this correlation function R _ij , whether or not a sound source exists in the target region is determined. Is different from the acoustic input device according to the fourth embodiment. In addition, about the component similar to Embodiment 4, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The correlation function R _{ij in Equation} 8 is an autocorrelation function when i = j, and a cross-correlation function when i ≠ j.

The sound source position determination unit 21b of the present embodiment is different from the embodiment 4, 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 (k, m) relative ratio of the cross-correlation function _{R 01} of _(R 01 _{/ R 00)} first condition is included in the first preset range, the reference observation signal x0 (k relative to the autocorrelation function _{R 00} , M) and the second condition in which the relative ratio (R ₀₂ / R ₀₀ ) of the cross-correlation function R ₀₂ between the second observation signal x 2 (k, m) is included in a preset second range, the autocorrelation reference observation signal to the function _{R 00} x0 (k, m) and third observation signal x3 (k, m) a third range of relative ratio of the cross-correlation function _{R 03} of _(R 03 _{/ R 00)} is set in advance Reference observation for the third condition included in the above, autocorrelation function R ₀₀ The relative ratio (R ₀₄ / R ₀₀ ) of the cross-correlation function R ₀₄ between the signal x 0 (k, m) and the fourth observed power value Px 4 (k) is included in a preset fourth range. When all the conditions are satisfied, it is determined that the sound source exists in the target area. On the other hand, when any one of the first to fourth conditions is not satisfied, the sound source position determination unit 21b determines that the sound source does not exist in the target area.

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). The third range of the present embodiment is also a range greater than the initially set threshold value ξ and 1 or less (ξ <R ₀₃ / R ₀₀ ≦ 1). The fourth range of the present embodiment is also a range greater than the initially set threshold value ξ and 1 or less (ξ <R ₀₄ / R ₀₀ ≦ 1).

As described above, according to the present embodiment, the autocorrelation function R _{00 of the} reference observation signal x0 (k, m), the reference observation signal x0 (k, m), and the first to fourth observation signals x1 (k, m) to x4. By using the cross-correlation functions R _{01 to} R ₀₄ of (k, m), the influence of uncorrelated noise can be reduced and a high S / N ratio can be obtained, and whether or not the sound source exists in the target region is determined. The determination accuracy can be increased.

(Embodiment 6)
In the sound input device of the sixth embodiment, when the sound source position determination unit 21b illustrated in FIG. 10 satisfies any three conditions of the first to fourth conditions, the sound input areas of the four directional microphones 30 to 33 are included. When it is determined that a sound source is present in a portion where the three sound collection areas overlap, and any two conditions of the first to fourth conditions are satisfied, two sound collections of the four directional microphones 30 to 33 are collected. When it is determined that there is a sound source in the overlapping area and any one of the first to fourth conditions is satisfied, only one sound collection area among the sound collection areas of the four directional microphones 30 to 33 In the embodiment, it is determined that a sound source is present in a region other than the sound collection region of any of the four directional microphones 30 to 33 when it is determined that a sound source is present and none of the first to fourth conditions is satisfied. 4 acoustic inputs It is different from the location. In addition, about the component similar to Embodiment 4, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  When the sound source position determination unit 21b determines that the sound source exists in a portion where the three sound collection regions overlap among the sound collection regions of the four directional microphones 30 to 33, the output calculation unit 22b of the present embodiment (X1 (k, m) + x2 ′ (k, m) + x3 (k, m) + x4 ′ (k, m)) is amplified with a third amplification factor G3 smaller than the first amplification factor G1 and output. When the sound source position determination unit 21b determines that a sound source is present in a portion where the two sound collection regions overlap among the sound collection regions of the four directional microphones 30 to 33, the synthesized signal (x1 (k, m) + x2 ′ ( k, m) + x3 (k, m) + x4 ′ (k, m)) is amplified and output with a fourth amplification factor G4 smaller than the third amplification factor G3, and the four directivities are output by the sound source position determination unit 21b. Of the sound collection area of microphones 30-33 When it is determined that a sound source exists in only one sound collection region, the synthesized signal (x1 (k, m) + x2 ′ (k, m) + x3 (k, m) + x4 ′ (k, m)) is the fourth. When the sound source position determination unit 21b determines that a sound source is present in a region other than the sound collection region of the four directional microphones 30 to 33, with a fifth gain G5 smaller than the first gain G4. The synthesized signal (x1 (k, m) + x2 ′ (k, m) + x3 (k, m) + x4 ′ (k, m)) is amplified with a sixth amplification factor G6 smaller than the fifth amplification factor G5. Output.

  As described above, according to the present embodiment, it is possible to determine how far the sound source is located from the target area even when the sound source does not exist in the target area.

  When the sound source does not exist in the target area, the larger the number of overlapping sound collection areas of the plurality of directional microphones 30 to 33, the larger the amplification factor can be given, and the output signal y (k, m) The size can be changed step by step.

  Note that, similarly to the sixth embodiment, the sound input device according to the fifth embodiment can be determined according to the number that satisfies the condition among the first to fourth conditions, and the amplification factor can be changed.

(Embodiment 7)
In the acoustic input device of the second embodiment, the output signal y (k, m) (power value Py (k) of the output signal) is discontinuous with respect to the position where the sound source exists.

  Therefore, in the sound input device according to the seventh embodiment, when the sound source position determination unit 21a illustrated in FIG. 3 determines that the sound source does not exist in the target region, the sound input device determines whether the sound source exists in the vicinity of the target region. On the other hand, when the sound source position determination unit 21a determines that the sound source exists in the vicinity of the target area, the output calculation unit 22a continuously changes to monotonously decrease between the first gain G1 and the second gain G2. The second embodiment is different from the acoustic input device according to the second 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 2, the same code | symbol is attached | subjected and description is abbreviate | omitted.

As shown in FIG. 11, the amplification factor G is such that all of the first to fourth observed power values Px1 (k) to Px4 (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) and relative ratio | 10log ₁₀ (Px3 (k) / Px4 (k)) When | is 0 or more and less than the threshold ε (0 ≦ | ₁₀ log ₁₀ (Px3 (k) / Px4 (k)) | <ε), the first amplification factor G1 is obtained as in the second embodiment.

On the other hand, when the relative ratio | 10log ₁₀ (Px1 (k) / Px2 (k)) | or the relative ratio | 10log ₁₀ (Px3 (k) / Px4 (k)) | ₁₀ log ₁₀ (Px1 (k) / Px2 (k)) | or relative ratio | 10log ₁₀ (Px3 (k) / Px4 (k)) | is greater than or equal to threshold ε and less than threshold ε1 (ε1> ε) (ε ≦ | ₁₀ log ₁₀ When (Px1 (k) / Px2 (k)) | <ε1 or ε ≦ | 10log ₁₀ (Px3 (k) / Px4 (k)) | <ε1), it is determined that the sound source exists in the vicinity of the target region, The amplification factor G varies according to the monotone decreasing function f. Subsequently, the relative ratio | 10log ₁₀ (Px1 (k) / Px2 (k)) | or the relative ratio | 10log ₁₀ (Px3 (k) / Px4 (k)) | is equal to or greater than the threshold ε1 (ε1 ≦ | 10log ₁₀ (Px1 (K) / Px2 (k)) | or ε1 ≦ | 10log ₁₀ (Px3 (k) / Px4 (k)) |), it is determined that the sound source exists at a position away from the target region, and the amplification factor G Becomes the second amplification factor G2.

  As described above, according to the present embodiment, the amplification factor G for amplifying the composite signal (x1 (k, m) + x2 ′ (k, m) + x3 (k, m) + x4 ′ (k, m)) is the sound source. It is possible to prevent discontinuity depending on the location, and as a result, the output signal y (k, m) (power value Py (k) of the output signal) can always be a continuous value.

  As shown in FIG. 12, in the sound input devices of Embodiments 4 and 5, the sound source is used when all of the first to fourth conditions are not satisfied but three conditions of the first to fourth conditions are satisfied. The amplification factor G can be increased as the position is closer to the region.

  In the acoustic input devices of Embodiments 4 and 5, the output signal y (k, m) (power value Py (k) of the output signal) is discontinuous with respect to the position where the sound source exists.

  Therefore, when the sound source position determination unit 21a illustrated in FIG. 3 determines whether or not the sound source exists in the vicinity of the target region, and determines that the sound source exists in the vicinity of the target region, the output calculation unit 22a performs the first operation. The synthesized signal is amplified and output with an amplification factor of a continuous change characteristic that monotonically increases between the amplification factor G1 and the second amplification factor G2.

  Here, the ratio of the reference observed power value Px0 (k) and the observed power values Px1 (k) to Px4 (k) is δ1 <Pxi (k) / Px0 (k) <δ, δ <Pxj (k) / Px0. (K) ≦ 1, δ <Pxk (k) / Px0 (k) ≦ 1, δ <Pxl (k) / Px0 (k) ≦ 1 (i, j, k, l are 1, 2, 3, 4 13), it is determined that there is a sound source in the vicinity of the portion where the sound collection areas of the three directional microphones 30 to 33 overlap and the portion where the sound collection areas of the four directional microphones 30 to 33 overlap. As shown, the amplification factor G varies according to a monotonically increasing function g having Pxi (k) / Px0 (k) as a variable.

  Subsequently, the ratio between the reference observation power value Px0 (k) and the observation power values Px1 (k) to Px4 (k) is δ1 <Pxi (k) / Px0 (k) <δ, δ1 <Pxj (k) / Px0. (K) <δ, δ <Pxk (k) / Px0 (k) ≦ 1, δ <Pxl (k) / Px0 (k) ≦ 1 (i, j, k, l are 1, 2, 3, 4 13), it is determined that there is a sound source in the vicinity of the portion where the sound collection areas of the two directional microphones 30 to 33 overlap and the portion where the sound collection areas of the four directional microphones 30 to 33 overlap. As shown, the amplification factor G varies according to a monotonically increasing function g with the smaller one of Pxi (k) / Px0 (k) or Pxj (k) / Px0 (k) as a variable.

  Furthermore, as illustrated in FIG. 14, in the sound input device according to the sixth embodiment, when the number of overlapping sound collection regions of the directional microphones 30 to 33 changes, the gain G may be continuously changed. Good.

As for the acoustic input device of the third embodiment, the amplification factor G is the same as that of the third embodiment when the cross-correlation function R ₁₂ and the cross-correlation function R ₃₄ are larger than the threshold value Rth as shown in FIG. Gain G1.

On the other hand, if the cross-correlation function _{R 12} or the cross-correlation function _{R 34} is equal to or smaller than the threshold Rth, when the cross-correlation function _{R 12} is from greater threshold Rth than the threshold value Rth1 of (Rth1 _{<R 12} ≦ Rth), or cross-correlation function when R ₃₄ is from greater threshold Rth than the threshold value Rth1 of (Rth1 _{<R 34} ≦ Rth), the sound source is determined to be present in the vicinity of the target area, the amplification factor G varies according monotonically increasing function e.

In the acoustic input device of the fifth embodiment, the relative ratio of the cross-correlation functions R _{01 to} R ₀₄ with respect to the autocorrelation function R ₀₀ of the reference observation signal x ₀ is _ξ1 <R _0i / R ₀₀ ≦ ξ, ξ <R _0j / R ₀₀ ≦ 1, ξ <R _0k / R ₀₀ ≦ 1, ξ <R _0l / R ₀₀ ≦ 1 (i, j, k, l: 1, 2, 3, 4) 3 It is determined that there is a sound source in the vicinity of the portion where the sound collection regions of the four directional microphones 30 to 33 overlap and the portion where the sound collection regions of the four directional microphones 30 to 33 overlap, and as shown in FIG. Fluctuates according to a monotonically increasing function h with R _0i / R ₀₀ as a variable.

Subsequently, the relative ratio of the cross-correlation functions R _{01 to} R ₀₄ with respect to the autocorrelation function R ₀₀ of the reference observation signal x ₀ is ξ 1 <R _0i / R ₀₀ ≦ ξ, ξ 1 <R _0j / R ₀₀ ≦ ξ, ξ <R _{When 0 k} / R ₀₀ ≦ 1 and ξ <R 0 _l / R ₀₀ ≦ 1 (i, j, k, l: any one of 1, 2, 3, 4), the collection of two directional microphones 30 to 33 It is determined that a sound source exists in the vicinity of the portion where the sound region overlaps and the portion where the sound collection regions of the four directional microphones 30 to 33 overlap. As shown in FIG. 16, the amplification factor G is R _0i / R ₀₀ or R _0j. It fluctuates according to a monotonically increasing function h with the smaller of / R ₀₀ as a variable.

(Embodiment 8)
In the acoustic input device of the fourth embodiment, the interval between the two microphone modules 10 (first and second directional microphones 30 and 31) and 11 (third and fourth directional microphones 32 and 33) shown in FIG. 9 is reduced. As the distance to the target area C increases, the horizontal length b becomes shorter than the vertical length a of the target area C, that is, the aspect ratio b / a of the target area C decreases.

  Therefore, in the acoustic input device according to the eighth embodiment, the sound collection area of each microphone module can be changed. In addition, about the component similar to Embodiment 4, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 18, each of the directional microphones 30a to 33a has a configuration in which n omnidirectional microphones 4i1 to 4in (i = 0, 1, 2, 3) are arranged. In such a configuration, the directivity directions of the directional microphones 30a to 33a can be changed by using the filters 51 to 5n that match the phases of the observation signals of sound coming from an arbitrary direction. The direction of each of the directional microphones 30a to 33a can be mechanically changed.

  As described above, according to the present embodiment, as shown in FIG. 17, by changing the directivity direction of the first to fourth directional microphones 30 a to 33 a, not only in front of the sound collection unit 1 b but also in an arbitrary direction. The target area can also be set. As a result, while changing the sound collection region of the microphone module, for example, sound is continuously collected from adjacent regions in time, thereby increasing the aspect ratio b / a of the target region C and expanding the target region C. be able to.

(Embodiment 9)
As shown in FIG. 19, the acoustic input device of the ninth embodiment is different from the acoustic input device of the fourth embodiment in that a plurality of sound collecting units 1 b are arranged on the same straight line. In addition, about the component similar to Embodiment 4, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In the acoustic input device according to the present embodiment, the target areas C are arranged so as to be adjacent to each other, and the sound is simultaneously collected from the plurality of adjacent target areas C, thereby being equivalent to the sound collection from the area where the plurality of target areas C are combined. The effect of.

  As described above, according to the present embodiment, the target area C can be enlarged by increasing the aspect ratio b / a of the target area C by arranging a plurality of the sound collecting portions 1b on the same straight line.

(Embodiment 10)
The acoustic input device of the tenth embodiment is different from the acoustic input device of the fourth embodiment in that a plurality of sound collecting units 1b... Shown in FIG. 19 are arranged in parallel as shown in FIG. is doing. In addition, about the component similar to Embodiment 4, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The acoustic input device of this embodiment not only increases the aspect ratio b / a of the target area C, but also expands the target area C in the direction perpendicular to the sound collection unit 1b. A plurality of sound collecting portions 1b... Having the structure shown are arranged in parallel as shown in FIG. At this time, by arranging the target areas C so as to be adjacent to each other and simultaneously collecting sound from several adjacent target areas C, an effect equivalent to the sound collection from the area where the plurality of target areas C are combined is obtained.

  As described above, according to the present embodiment, by arranging a plurality of sound collecting portions 1b... In parallel, not only the aspect ratio b / a of the target area C is increased, but also the direction perpendicular to the sound collecting portion 1b. The target area C can be enlarged.

(Embodiment 11)
The acoustic input device according to the eleventh embodiment is different from the acoustic input device according to the fourth embodiment in that the sound collecting units 1b are two-dimensionally arranged. In addition, about the component similar to Embodiment 4, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  Consider collecting sound not only from the front area of the sound collecting section 1b but also from the side area. At this time, as shown in FIG. 21, if a plurality of sound collecting portions 1b are arranged so that the microphone modules are arranged on a concentric circle having the diameter of the sound collecting portion 1b, sound can be collected also from the side region. it can.

  As described above, according to the present embodiment, for example, by providing the microphone modules so as to be arranged on a circle having a diameter between the microphone modules of the sound collection unit 1b, not only the front region of the sound collection unit 1b but also the side region. Can also collect sound.

  In addition, the direction of the directional microphones 30a to 33a is changed, the adjacent target area C is set, the target area C is expanded by collecting sound continuously in time, and the sound is simultaneously collected from the adjacent target area C. Accordingly, the target area C can be enlarged.

  As a modification of the eighth to eleventh embodiments, the sound collecting unit 1a according to the second embodiment may be used instead of the sound collecting unit 1b. Even if it is such a structure, there exists an effect similar to Embodiment 8-11.

Embodiment 12
In the first to eleventh embodiments, the case of one sound source has been described. In the twelfth 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. 22A, the target sound source S exists in an area where the sound collection areas of the first to fourth directional microphones 30 to 33 overlap, and the first to fourth directional microphones 30 to The case where the noise source N1 exists in the area | region where the sound collection area | region of any one or two directional microphones among 33 will overlap is demonstrated.

In the case shown in FIG. 22A, among the sound source position determination conditions of the first embodiment, Pxi (k)> Pth (i = 1, 2, 3, 4) (first condition) is satisfied, but the first Since the noise source N1 exists only in any one or two of the directional microphones 30 to 33 of ˜4, | 10log ₁₀ (Px1 (k) / Px2 (k) | <ε (second Condition) and | 10log ₁₀ (Px3 (k) / Px4 (k) | <ε (third condition).

When the first condition is satisfied but the second and third conditions are not satisfied as described above, the sound source position determination conditions R ₁₂ > Rth (fourth condition) and R ₃₄ > Rth (fifth condition) of the third embodiment are further used. . Since the signal based on the target sound source S is included in all of the first to fourth observation signals x1 (t) to x4 (t) of the first to fourth directional microphones 30 to 33, the fourth and fifth conditions are satisfied. . Therefore, the sound source position determination unit 21a can determine that the target sound source S exists in an area where the sound collection regions of the first to fourth directional microphones 30 to 33 overlap.

  Subsequently, the sound source position determination unit 21a needs to determine which of the first to fourth directional microphones 30 to 33 the noise source N1 is in an area where the sound collection regions of the directional microphones overlap. Therefore, as shown in FIG. 22A, the omnidirectional microphone 12 is disposed between the two microphone modules. 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 position determination unit 21a among the observed power values Px1 (k) to Px4 (k) of the first to fourth directional microphones 30 to 33, δ <Pxi (k) / Px0 (k) ≦ 1 ( i = 1, 2, 3, 4) It is determined that the noise source N1 exists in the sound collection region of the first to fourth directional microphones 30 to 33 satisfying (sixth condition).

  The target sound source S exists in an area where the sound collection areas of the first to fourth directional microphones 30 to 33 overlap, and the noise source N1 is any one of the sound collection areas of the first to fourth directional microphones 30 to 33. When it is determined that one or two sound collection areas are present in the overlapping area, the observation signal of any one of the first to fourth directional microphones 30 to 33 including only the signal based on the output calculation unit 22b and the target sound source S Discrete values x1 (k, m) to x4 (k, m) are amplified with an amplification factor G1, and an output signal y (k, m) = G1 × xi (k, m) (i = 1, 2, 3, 4) 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 to fourth directional microphones 30 to 33 overlap, the output calculation unit 22b outputs the first to fourth directional microphones 30 to 33. Amplifying a composite signal (x1 (k, m) + x2 (k, m) + x3 (k, m) + x4 (k, m)) of discrete values x1 (k, m) to x4 (k, m) Amplified at a rate G2 (G1> G2) and outputs an output signal y (k, m) = G2 (x1 (k, m) + x2 (k, m) + x3 (k, m) + x4 (k, m)) .

  As described above, according to the present embodiment, the target sound source S exists in an area where the sound collection areas of the first to fourth directional microphones 30 to 33 overlap, and the noise source N1 is the first to fourth directional microphones 30 to 33. In the case where any one or two of the sound collection areas are in an overlapping area, only the signal based on the target sound source S can be amplified and output.

  As a modification of the twelfth embodiment, the output signal y (k, m) can be output as follows. In the sound source position determination unit 21a, the target sound source S exists in an area where the sound collection regions of the first to fourth directional microphones 30 to 33 overlap, and the noise source N1 is the first directional microphone 30 to 33. When it is determined that only one or two sound collection areas exist in the overlapping area, the noise source N1 is included in the sound collection area until the second and third conditions are satisfied as shown in FIG. Discrete values x1 (k, m) to x4 (k, m) of the observation signals of the first to fourth directional microphones 30 to 33 after the directional axes of the one or two directional microphones 30 to 33 are tilted. Signal (x1 (k, m) + x2 (k, m) + x3 (k, m) + x4 (k, m)) is amplified with an amplification factor G1, and the output signal y (k, m) = G1 (x1 ( k, m) + x2 (k, m) + x3 (k, m) + x4 (k, m)) That. The case where the target sound source S does not exist in the area where the sound collection areas of the first to fourth directional microphones 30 to 33 overlap is the same as that of the twelfth embodiment.

(Embodiment 13)
In the twelfth embodiment, the case of two sound sources has been described. In the thirteenth 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. 23A, the target sound source S exists in an area where the sound collection areas of the first to fourth directional microphones 30 to 33 overlap, and the first to fourth directional microphones 30 to The noise source N1 exists in an area where any one or two sound collection regions of 33 overlap, and one or two directivity different from the directional microphones 30 to 33 included in the sound collection region. A case where the noise source N2 exists in an area where the sound collection areas of the directional microphones 30 to 33 overlap will be described.

In the case shown in FIG. 23A, among the sound source position determination conditions of the first embodiment, Pxi (k)> Pth (i = 1, 2, 3, 4) (first condition) is satisfied, but the first The noise source N1 exists only in one or two of the four directional microphones 30 to 33, and any one of the first to fourth directional microphones 30 to 33 where the noise source N1 does not exist. Since the noise source N2 exists only in one or two sound collection regions, | 10log ₁₀ (Px1 (k) / Px2 (k) | <ε (second condition) and | 10log ₁₀ (Px3 (k) / Px4 (k) | <ε (third condition) is not always satisfied.

When the first condition is satisfied but the second and third conditions are not satisfied as described above, the sound source position determination conditions R ₁₂ > Rth (fourth condition) and R ₃₄ > Rth (fifth condition) of the third embodiment are further satisfied. Is used. Since the signal based on the target sound source S is included in all of the first to fourth observation signals x1 (t) to x4 (t) of the first to fourth directional microphones 30 to 33, the fourth and fifth conditions are satisfied. . Therefore, the sound source position determination unit 21a can determine that the target sound source S exists in an area where the sound collection regions of the first to fourth directional microphones 30 to 33 overlap.

  Subsequently, the sound source position determination unit 21a needs to determine which of the first to fourth directional microphones 30 to 33 has the noise sources N1 and N2 in the area where the sound collection areas of the directional microphones overlap. is there. Therefore, as shown in FIG. 23A, the omnidirectional microphone 12 is disposed between the two microphone modules. Since the omnidirectional microphone 12 is omnidirectional, a signal based on the target sound source S and the noise sources N1 and N2 is included in the reference observation signal x0 (t). Therefore, the sound source position determination unit 21a includes the omnidirectional microphone 12 and the first to fourth directional microphones when the noise sources N1 and N2 exist outside the sound collection region of the first to fourth directional microphones 30 to 33. Among the observed power values Px1 (k) to Px4 (k) of the first to fourth directional microphones 30 to 33, with the ratio δ2 of the observed power values 30 to 33 as a threshold, δ2 <Pxi (k) / Px0 ( k) ≦ δ (i = 1, 2, 3, 4) (sixth condition) It is determined that the noise sources N1 and N2 exist in an area where the sound collection areas of one or two directional microphones 30 to 33 overlap. To do.

  The target sound source S exists in an area where the sound collection areas of the first to fourth directional microphones 30 to 33 overlap, and the noise source N1 is any one or two of the first to fourth directional microphones 30 to 33. The noise source N2 exists in an area where the sound collection areas of the one or two directional microphones 30 to 33 that are present in the area where the sound collection areas overlap and the noise source N1 is different from the directional microphones included in the sound collection area overlap. If it is determined that the sound source exists, Max (α1 / 2, α2) from the central axis of the area where the noise collection area of the first and second directional microphones 30, 31 overlaps the noise source N1, as shown in FIG. / 2) When the noise source N2 is more than Max (α3 / 2, α4 / 2) away from the central axis of the area where the sound collection areas of the third and fourth directional microphones 32 and 33 overlap It is shown in Fig. 23 (b) By tilting the directional axes of the first and second directional microphones 30 and 31 until the second condition is satisfied, and tilting the directional axes of the third and fourth directional microphones 32 and 33 until the third condition is satisfied, Only signals based on the sound source S can be collected by the first to fourth directional microphones 30 to 33. At this time, the output calculation unit 22b generates a composite signal (x1 (k, m) + x2) of discrete values x1 (k, m) to x4 (k, m) of the observation signals of the first to fourth directional microphones 30 to 33. (K, m) + x3 (k, m) + x4 (k, m)) is amplified with an amplification factor G1, and the output signal y (k, m) = G1 (x1 (k, m) + x2 (k, m) + x3 (K, m) + x4 (k, m)) is output.

  On the other hand, when the target sound source S does not exist in the area where the sound collection areas of the first to fourth directional microphones 30 to 33 overlap, the output calculation unit 22b outputs the first of the first to fourth directional microphones 30 to 33. A composite signal (x1 (k, m) + x2 (k, m) + x3 (k, m) + x4 (k, m)) of discrete values x1 (k, m) to x4 (k, m) of the observed signals of ˜4 Is amplified at an amplification factor G2 (G1> G2), and an 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 to fourth directional microphones 30 to 33 overlap, and any one of the first to fourth directional microphones 30 to 33 is present. Even when different noise sources N1 and N2 exist in an area where one or two sound collection regions overlap, a signal based on the target sound source S can be emphasized and output.

  As shown in FIG. 24 (a), at least one of the noise source N1 and the noise source N2 is Max (α1 / 2) from the central axis of the area where the first and second directional microphones 30 and 31 overlap. , Α2 / 2) or greater than Max (α3 / 2, α4 / 2) or greater than the central axis of the area where the collection regions of the third and fourth directional microphones 32, 33 overlap. Even if the directional axes of the -4 directional microphones 30 to 33 are tilted, only the signal based on the target sound source S cannot be collected. However, the signal based on the target sound source S is included in all of the first to fourth observation signals x1 (t) to x4 (t) of the first to fourth directional microphones 30 to 33, and the signal based on the noise source N1 is A signal based on the noise source N2 is based on the noise source N1 only in the observation signals x1 (t) to x4 (t) of any one or two of the first to fourth directional microphones 30 to 33. Since the signals are included only in the observation signals x1 (t) to x4 (t) of one or two directional microphones 30 to 33 different from the directional microphones including the signals, the first to fourth directional microphones 30 to 33. A composite signal (x1 (k, m) + x2 (k, m) + x3 (k, m) + x4 (k) of the discrete values x1 (k, m) to x4 (k, m) of the first to fourth observation signals. , M)) are amplified with an amplification factor G1 and output. , It is possible to emphasize the signal based on the target sound source S than for collecting only non-directional microphone 12.

  Note that the acoustic input devices of the twelfth and thirteenth embodiments perform (1) only the target sound source and (2) the target sound source and one noise source by performing the determination operation as shown in FIG. (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. It is a figure for demonstrating operation | movement of an acoustic input device same as the above. It is a block diagram which shows the structure of the acoustic input device of Embodiment 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 microphone and a 2nd microphone in the acoustic input device of Embodiment 2-5. FIG. 10 is a diagram for explaining the characteristics of a modified example of the first directional microphone and the second directional microphone in the acoustic input device according to the second embodiment. FIG. 10 is a diagram for explaining characteristics of another modification of the first directional microphone and the second directional microphone in the sound 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 figure for demonstrating operation | movement of the acoustic input device of Embodiment 4. It is a block diagram which shows the structure of the acoustic input device of Embodiment 4-6. It is a figure which shows the gain in the acoustic input device of Embodiment 7. 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. 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 acoustic input device according to the eighth embodiment. It is a block diagram which shows the structure of the acoustic input device of Embodiment 9. It is a figure for demonstrating operation | movement of an acoustic input device same as the above. It is a figure for demonstrating operation | movement of the acoustic input device of Embodiment 10. FIG. It is a figure for demonstrating operation | movement of the acoustic input device of Embodiment 11. FIG. FIG. 20 is a diagram for explaining the operation of the acoustic input device according to the twelfth embodiment. FIG. 20 is a diagram for explaining the operation of the sound input device according to the thirteenth embodiment. It is a figure for demonstrating operation | movement of an acoustic input device same as the above. It is a flowchart which shows operation | movement of the acoustic input device of Embodiment 12, 13.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sound collecting part 10 1st microphone module 11 2nd microphone module 2 Signal processing part 20 Phase difference correction part 21 Sound source position determination part 22 Output calculating part

Claims (14)

Each having a microphone module a pair that have a pickup area having a predetermined directivity angle, the microphone module of the one pair such that each sound collecting area intersect is installed, the collector of the pair of microphones module A sound collection unit having a target region as a region where the sound regions overlap ; each microphone module has a pair of directional microphones, and each of the pair of directional microphones has a sound collection region having a predetermined directivity angle; And receiving a sound wave from the sound source existing in the sound collection area, generating an observation signal based on the received sound wave, and a part of each sound collection area of the pair of directional microphones is the target area A sound input device installed in close proximity so as to overlap ,
An omnidirectional microphone installed at an intermediate position between the pair of microphone modules to receive a sound wave from the sound source and generate a reference observation signal based on the received sound wave;
For each of the microphone modules, the observation signal is received from each of the pair of directional microphones, and the phase difference between the two received observation signals is expressed as 2 when the sound source exists in a predetermined target direction. A phase difference correction unit that corrects only the phase difference of two observation signals;
A sound source position determination unit that determines whether or not the sound source exists in the target region using each observation signal after being corrected by the phase difference correction unit ;
When the sound source position determination unit determines that the sound source is present in the target region, a synthesized signal of the observation signals after the phase difference of the observation signals is corrected by the phase difference is a first amplification factor. in one that amplifies and outputs, if the sound source by the sound source position determination unit determines not present in the target area, and outputs the combined signal is amplified by the first amplification factor is smaller than the amplification factor An output calculation unit ,
The phase difference correction unit further receives the reference observation signal, and calculates a phase difference between the received reference observation signal and any one of the received observation signals as a reference when the sound source exists in the target region. Correct only the phase difference between the observed signal and the observed signal,
The power value of the observation signal for each microphone module after correction by the phase difference correction unit is used as an observation power value, and the power value of the reference observation signal after correction by the phase difference correction unit is used as a reference observation. Power value,
The sound source position determination unit
A first condition in which a relative ratio of one observation power value to the reference observation power value in one microphone module is included in a preset first range, and a relative ratio of the other observation power value to the reference observation power value is A second condition included in a preset second range; a third condition in which a relative ratio of one observation power value to the reference observation power value in the other microphone module is included in a preset third range; When the relative ratio of the other observation power value to the reference observation power value satisfies all the conditions of the fourth condition included in the preset fourth range, the sound source is determined to exist in the target area,
An acoustic input device that determines that the sound source does not exist in the target area when any one of the first to fourth conditions is not satisfied . Each of the microphone modules has a pair of microphone modules each having a sound collection area with a predetermined directivity angle, and the pair of microphone modules are installed so that the sound collection areas intersect, and the sound collection areas of the pair of microphone modules overlap. includes a sound collector aimed region regions, each microphone module includes a pair of directional microphones, the pair of directional microphones, each having a sound collection region of the directivity angle of the constant Tokoro the A sound wave from the sound source existing in the sound collection area is received and an observation signal based on the received sound wave is generated, and a part of each sound collection area of the pair of directional microphones includes the target area. An acoustic input device installed in close proximity so as to overlap ,
An omnidirectional microphone installed at an intermediate position between the pair of microphone modules to receive a sound wave from the sound source and generate a reference observation signal based on the received sound wave;
Before each Kemah Lee black phone module receives the observation signals from the respective directional microphone of the one pair, the phase difference between two of said observation signal the received exists in the target direction in which the sound source is predetermined A phase difference correction unit that corrects only the phase difference between the two observation signals in the case ,
A sound source position determination unit that determines whether previous SL sound with each observation signal after being corrected is present in the target area in the previous SL phase difference correcting unit,
When the sound source position determination unit determines that the sound source is present in the target region, a synthesized signal of the observation signals after the phase difference of the observation signals is corrected by the phase difference is a first amplification factor. On the other hand, when the sound source position determination unit determines that the sound source does not exist in the target area, the composite signal is amplified and output with an amplification factor smaller than the first amplification factor. An output calculation unit,
The phase difference correction unit extracts a discrete value of each received observation signal at a predetermined time interval, further receives the reference observation signal, and extracts a discrete value of the reference observation signal at the predetermined time interval,
The sound source position determination unit
For each microphone module, a correlation function R _ij (i, j = 0, 1, 2, 3, 4) represented by Equation 2 using the discrete values x1 to x4 of the observation signal and the discrete value x0 of the reference observation signal is obtained. Seeking
In one microphone module, a first condition in which a relative ratio of the cross-correlation function R ₀₁ to the auto-correlation function R ₀₀ is included in a preset first range, a relative ratio of the cross-correlation function R ₀₂ to the auto-correlation function R ₀₀ Is a second condition that is included in a preset second range, and the third condition is that the relative ratio of the cross-correlation function R ₀₃ to the autocorrelation function R ₀₀ in the other microphone module is included in a preset third range. When the relative ratio of the cross-correlation function R ₀₄ to the auto-correlation function R ₀₀ satisfies all of the fourth conditions included in the preset fourth range, it is determined that the sound source exists in the target area. on the other hand,
If not satisfied in any one condition of the first to fourth conditions, characteristics and be Ruoto sound input device that determines that the sound source is not present in the target area.

The sound source position determination unit
When any three conditions of the first to fourth conditions are satisfied, it is determined that the sound source exists in a portion where three sound collection areas of the sound collection areas of the four directional microphones overlap.
When any two conditions of the first to fourth conditions are satisfied, it is determined that the sound source exists in a portion where two sound collection areas overlap among the sound collection areas of the four directional microphones,
When any one of the first to fourth conditions is satisfied, it is determined that the sound source is present only in one sound collection region among the sound collection regions of the four directional microphones,
Wherein when not satisfied any of the conditions of the first to fourth conditions, four acoustic claim 1 or 2, wherein the sound source in the region not in any sound collection region of directional microphones is characterized by determining that there Input device. The output calculation unit is
When it is determined by the sound source position determination unit that the sound source exists in a portion where three sound collection areas of the four sound collecting areas of the directional microphone overlap, a third signal smaller than the first amplification factor is used as the synthesized signal. Amplified with an amplification factor of
When it is determined by the sound source position determination unit that the sound source is present in a portion where two sound collection areas of the four directional microphone sound collection areas overlap, the synthesized signal is converted to a fourth smaller than the third amplification factor. Amplified with an amplification factor of
When the sound source position determination unit determines that the sound source exists in only one sound collection region of the four sound collection regions of the directional microphone, the synthesized signal is set to a fifth smaller than the fourth amplification factor. Amplified with an amplification factor of
When the sound source position determination unit determines that the sound source exists in a region other than the sound collection region of the four directional microphones, the synthesized signal is amplified with a sixth amplification factor smaller than the fifth amplification factor. acoustic input device according to claim 3, characterized in that to the output. Each of which has a pair of microphone modules each having a sound collection region having a predetermined directivity angle and receiving a sound wave from a sound source existing in the sound collection region and generating a reception signal based on the received sound wave; The pair of microphone modules is installed so that the sound collection areas intersect, and a sound collection unit whose target area is an area where the sound collection areas overlap each other,
A sound source position determination unit that determines whether or not the sound source is present in the target region using received signals generated by each of the pair of microphone modules;
When the sound source position determination unit determines that the sound source is present in the target area, the phase difference between the two received signals is the phase difference between the two received signals when the sound source is present in the target area. When the composite signal of the two received signals after being corrected only is amplified with the first amplification factor and output, while the sound source position determination unit determines that the sound source does not exist in the target region An output operation unit for amplifying the synthesized signal with an amplification factor smaller than the first amplification factor and outputting the amplified signal,
The sound source position determination unit determines whether or not the sound source exists in the vicinity of the target region when it is determined that the sound source does not exist in the target region,
When the sound source position determination unit determines that the sound source is present in the vicinity of the target area, the output calculation unit has a continuously changing characteristic that monotonously decreases from the first gain as the distance from the target position increases. features and to Ruoto sound input device to output an amplification factor and amplifies the combined signal. Acoustic input device according to any one of claims 1 to 5, wherein the sound collecting area of the respective microphone module can vary. Acoustic input device according to any one of claims 1 to 5, characterized in that it comprises the sound collecting unit arranged plurality collinear. Acoustic input device according to any one of claims 1 to 5, characterized in that it comprises side by side in parallel with the sound collecting unit by plurality. Acoustic input device according to any one of claims 1 to 5, characterized in that it comprises the sound collecting unit plurality, two-dimensionally arranged. Each of the microphone modules has a pair of microphone modules each having a sound collection area with a predetermined directivity angle, and the pair of microphone modules are installed so that the sound collection areas intersect, and the sound collection areas of the pair of microphone modules overlap. The microphone module has a pair of directional microphones, and each of the pair of directional microphones has a sound collection region with a predetermined directivity angle. A sound wave from the sound source existing in the sound region is received and an observation signal based on the received sound wave is generated, and a part of each sound collection region of the pair of directional microphones overlaps with the target region. A sound input device installed in close proximity,
An omnidirectional microphone installed at an intermediate position between the pair of microphone modules to receive a sound wave from the sound source and generate a reference observation signal based on the received sound wave;
For each of the microphone modules, the observation signal is received from each of the pair of directional microphones, and the phase difference between the two received observation signals is expressed as 2 when the sound source exists in a predetermined target direction. A phase difference correction unit that corrects only the phase difference of two observation signals;
A sound source position determination unit that determines whether or not the sound source exists in the target region using each observation signal after being corrected by the phase difference correction unit;
When the sound source position determination unit determines that the sound source is present in the target region, a synthesized signal of the observation signals after the phase difference of the observation signals is corrected by the phase difference is a first amplification factor. On the other hand, when the sound source position determination unit determines that the sound source does not exist in the target area, the composite signal is amplified and output with an amplification factor smaller than the first amplification factor. An output calculation unit,
The phase difference correction unit further receives the reference observation signal, and uses the phase difference between the received reference observation signal and any one of the received observation signals as a reference observation when a sound source exists in the target direction. Correct only the phase difference between the signal and the observed signal,
The power value of the observation signal for each microphone module after being corrected by the phase difference correction unit is set as the first to fourth observation power values, and the reference observation signal after being corrected by the phase difference correction unit Use the power value as the reference observation power value,
The sound source position determination unit
When any of the first to fourth observation power values is greater than a predetermined threshold and the relative ratio of the two observation power values is equal to or greater than a predetermined first set value in each microphone module, the microphone module in each microphone module When the cross-correlation function of two observation signals satisfies a condition that is equal to or greater than a predetermined second set value obtained from the autocorrelation function of each observation signal, the sound source is in the target region and other than the target region. While determining that each of the areas exists, when the condition is not satisfied, it is determined that the sound source does not exist in the target area,
When it is determined that the sound source exists in each of the target area and the other area for each microphone module, a relative ratio of at least one of the two observed power values to the reference observed power value is set in advance. when included in a range that is, characteristics and be Ruoto sound input device that determines that the sound source to at least one is present among the sound collecting areas of the pair of directional microphones. When the sound source position determination unit determines that the sound source exists in at least one of the sound collection regions of each directional microphone and the target region among the other regions, The acoustic input device according to claim 10 , wherein 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 to fourth directional microphones;
When the sound source position determination unit determines in each microphone module that the sound source exists in one of the target region and the sound collection region of the pair of directional microphones among the other regions, Controlling the driving means until a relative ratio of a pair of observed power values satisfies a condition that the relative ratio is less than the first set value;
When the sound source position determination unit determines that the sound source exists in the sound collection region of the pair of directional microphones after driving the driving unit, the output calculation unit is configured to observe the pair of observations after driving the driving unit. When the synthesized signal is amplified by the first amplification factor and output, and the sound source position determining unit determines that the sound source does not exist in the target area, the synthesized signal is amplified by the first amplification. The sound input device according to claim 11 , wherein the sound input device amplifies and outputs at a second amplification factor smaller than the rate . Each of the microphone modules has a pair of microphone modules each having a sound collection area with a predetermined directivity angle, and the pair of microphone modules are installed so that the sound collection areas intersect, and the sound collection areas of the pair of microphone modules overlap. The microphone module has a pair of directional microphones, and each of the pair of directional microphones has a sound collection region with a predetermined directivity angle. A sound wave from the sound source existing in the sound region is received and an observation signal based on the received sound wave is generated, and a part of each sound collection region of the pair of directional microphones overlaps with the target region. A sound input device installed in close proximity,
An omnidirectional microphone installed at an intermediate position between the pair of microphone modules to receive a sound wave from the sound source and generate a reference observation signal based on the received sound wave;
For each of the microphone modules, the observation signal is received from each of the pair of directional microphones, and the phase difference between the two received observation signals is expressed as 2 when the sound source exists in a predetermined target direction. A phase difference correction unit that corrects only the phase difference of two observation signals;
A sound source position determination unit that determines whether or not the sound source exists in the target region using each observation signal after being corrected by the phase difference correction unit;
When the sound source position determination unit determines that the sound source is present in the target region, a synthesized signal of the observation signals after the phase difference of the observation signals is corrected by the phase difference is a first amplification factor. On the other hand, when the sound source position determination unit determines that the sound source does not exist in the target area, the composite signal is amplified and output with an amplification factor smaller than the first amplification factor. An output calculation unit,
The phase difference correction unit further receives the reference observation signal, and uses the phase difference between the received reference observation signal and any one of the received observation signals as a reference observation when a sound source exists in the target direction. Correct only the phase difference between the signal and the observed signal,
The power value of the observation signal for each of the microphone modules after being corrected by the phase difference correction unit is defined as first to fourth observation powers, and the power of the reference observation signal after being corrected by the phase difference correction unit Let the value be the reference observation power value,
The sound source position determination unit
When all of the first to fourth observation power values are larger than a predetermined threshold, a predetermined setting in which the cross-correlation function of the two observation signals in each microphone module is obtained from the autocorrelation function of each observation signal When the condition that is greater than or equal to the value is satisfied, it is determined that the sound source exists in each of the target region and other regions other than the target region, and when the condition is not satisfied, the sound source does not exist in the target region. And
When it is determined that the sound source exists in each of the target area and the other area for each microphone module, a relative ratio of at least one of the two observed power values to the reference observed power value is set in advance. when included in a range that is, characteristics and be Ruoto sound input device that determines that the sound source is present in each of the sound collection region of the pair of directional microphones. Drive means for tilting the directional axis of the first to fourth directional microphones;
When the sound source position determination unit determines in each microphone module that the sound source exists in both the target area and the sound collection area of the pair of directional microphones among the other areas, When the two sound sources in the region are separated from the target region by more than half of the maximum value of the directivity angle of the two directional microphones of each microphone module, the relative ratio of the two observed power values is a predetermined value. Controlling the driving means until a condition that is less than a set value is satisfied,
When the sound source position determination unit determines that the sound source exists in the sound collection region of the pair of directional microphones after driving the driving unit, the output calculation unit is configured to observe the pair of observations after driving the driving unit. When the synthesized signal is amplified by the first amplification factor and output, and the sound source position determining unit determines that the sound source does not exist in the target area, the synthesized signal is amplified by the first amplification. 14. The sound input device according to claim 13 , wherein the sound input device amplifies and outputs at a second gain smaller than the rate .

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