JP4928382B2 - Specific direction sound collection device, specific direction sound collection method, specific direction sound collection program, recording medium - Google Patents

Description

  The present invention relates to a sound collection device that acquires a voice in a hands-free manner, such as a voice call or operation of a device. The present invention relates to a specific direction sound collection device, a specific direction sound collection method, a specific direction sound collection program, and a recording medium on which a specific direction sound collection program is recorded.

In the prior art, as shown in FIG. 1, microphones mic. Arranged at _M different positions (p ₁ , q ₁ ) to (p _M , q _M ) on the xy plane are used. 1-mic. Using M, sound generated from a sound source in an arbitrary angle θ _S direction is used as a signal, sound generated in other directions is used as noise, and only the signal is emphasized with a high signal-to-noise ratio (SNR). Collect sound. FIG. 2 is a block diagram showing the configuration of a conventional enhanced sound collection method. The signal x _m (n) (m = 1... M) received by the microphone m arranged at the position (x _m , y _m ) is added by adding a delay D _m as shown in the equation (1). Obtain y _m (n).

y _m (n) = x _m (n−D _m ) (1)
At this time, the delay amount D _m can be derived from the desired sound source direction θ _S given in advance by the equation (2).

D _m = (d _m / c) sin θ _S (2)
Where c is the speed of sound, d _m is when viewed from the sound wave arriving from theta _S direction in FIG. 1, the distance between the microphone m and a reference point is represented by the formula (3).

d _m = p _m sin θ + q _m cos θ (3)
Next, y _m (n) obtained now is added as shown in Expression (4) to obtain a signal z (n) that emphasizes the sound emitted from the desired position.

以上が従来の強調収音法（非特許文献１）である。この従来技術で形成される指向特性には図３に示すように、主ビームＢＭに近接して比較的大きい利得を持つサイドローブＳＢとよばれる領域が生じるため、雑音を十分に抑圧することができない。またこのサイドローブＳＢの利得を極力小さく抑えるためには、マイクロホン数を増やし、またマイクロホンアレーを大型にする必要がある（非特許文献１）。
大賀寿郎、山崎芳男、金田豊共著、音響システムとディジタル処理、電子情報通信学会 Ｐ．１８１〜Ｐ．１８６ ７．１．２．

The above is the conventional enhanced sound collection method (Non-Patent Document 1). As shown in FIG. 3, in the directivity characteristic formed by this conventional technique, a region called a side lobe SB having a relatively large gain is generated in the vicinity of the main beam BM, so that noise can be sufficiently suppressed. Can not. In order to keep the gain of the side lobe SB as small as possible, it is necessary to increase the number of microphones and increase the size of the microphone array (Non-Patent Document 1).
Toshiro Oga, Yoshio Yamazaki, Yutaka Kaneda, Acoustic systems and digital processing, IEICE 181-P. 186 7.1.2.

  When the sound collecting device is directed to a specific direction using conventional technology, the sound emitted in that direction is emphasized, and the sound emitted in other directions is suppressed and collected. The formed directivity has side lobes. Therefore, there has been a problem that sound emitted from the direction in which it is desired to be suppressed is collected without being sufficiently suppressed. For this reason, when there is a noise source that emits a very loud sound other than the direction of the sound source to be emphasized, the sound collecting device of the prior art cannot obtain a sufficient enhancement effect for the desired sound source. Further, in the prior art, in order to reduce the side lobes, the number of microphones must be increased and the microphone array must be increased in size, which is difficult to install and transport in practical use. Furthermore, since the directivity characteristics of the sound collecting device according to the prior art change depending on the frequency, there is a problem that a sufficient emphasis effect cannot be obtained depending on the frequency structure of the desired sound or noise.

  The present invention has been made to solve the above-described problems, and realizes an apparatus for enhancing and collecting sound from a desired sound source with an SNR higher than that of the prior art without increasing the scale of a microphone array. There is.

  The specific direction sound pickup apparatus of the present invention includes a plurality of beam former units, a plurality of frequency domain conversion units, a specific direction selection unit, a signal amount estimation unit, a gain coefficient calculation unit, and a multiplication unit. The beamformer unit collects sound by emphasizing sounds coming from angular regions in different directions using output signals of a microphone array configured by mounting a plurality of microphones. The frequency domain conversion unit converts each of the angle domain signals collected by the plurality of beam former units into a frequency domain signal divided into a plurality of band components. The specific direction selection unit selects a specific direction frequency domain signal belonging to an angle domain in a desired direction among the frequency domain signals output from each frequency domain conversion unit. The signal amount estimation unit includes a region aggregation unit, an inverse matrix calculation unit, and a multiplication unit. The region aggregating unit obtains an aggregate power vector composed of the signal amount of the specific direction frequency region signal and the signal amount of the angle region signal in the other direction. The inverse matrix calculation means obtains an inverse matrix of the aggregate gain matrix obtained from the directivity characteristics of the beam former unit. The multiplication means multiplies the aggregate power vector by an inverse matrix to obtain an estimated value of the total amount of frequency domain signals. The gain coefficient calculation unit calculates a gain coefficient for each frequency band based on a ratio between the signal amount of the specific direction frequency domain signal and the total amount of the frequency domain signals. The multiplying unit multiplies the gain coefficient calculated by the gain coefficient calculating unit by the signal amount of each corresponding frequency band of the specific direction frequency domain signal.

  According to the specific direction sound pickup device of the present invention, in order to improve the enhancement effect when collecting sound by enhancing a sound emitted from a sound source in a desired direction, a plurality of beamforms are obtained using signals received by a microphone array. The power of the sound signal emitted from each sound source is estimated from the result of the image processing, and the desired sound signal is enhanced using a nonlinear filter coefficient that enhances the signal in the sound collection region. Therefore, it is not necessary to increase the number of microphones or increase the size of the microphone array. In addition, the emphasis effect can be improved with a small system that is easy to install and transport in practice.

  Further, in the processing of the sound collecting apparatus in the specific direction of the present invention, the processing by the inverse matrix calculating means requires the longest calculation time. Since the signal amount estimation unit of the sound collecting apparatus of the specific direction according to the present invention uses a two-dimensional aggregate power vector, the aggregate gain matrix obtained from the directivity of the beamformer unit is also 2 rows and 2 columns. Therefore, the calculation amount of the entire process can be greatly reduced.

Principle FIG. 4 shows an example of the arrangement of the microphone array of the sound collecting device in a specific direction according to the present invention. In the present invention, as shown in FIG. 4, an area to be collected is divided into a plurality of direction areas, and a signal received by controlling the directivity of the microphone array to each direction area is used. At this time, the signal processed by the microphone array changes in power (also referred to as “signal amount”) in accordance with the direction in which the sound source exists, as compared to before the processing. In the present invention, the power of the signal arriving from each direction area is estimated using the amount of change in power. Then, a non-linear filter that emphasizes a signal arriving from a direction region given in advance is formed from the estimated power (a gain coefficient is obtained), and a signal that has passed through the filter is obtained as a final output signal. In order to reduce the amount of calculation, the direction areas are aggregated in the above-described signal power estimation.

Specific embodiments will be described below. In addition, the same number is attached | subjected to the component which performs the same function and the same process, and duplication description is abbreviate | omitted.
[First Embodiment]
First, an overall outline of the present invention will be described. FIG. 5 shows an example of the overall configuration of the specific direction sound pickup apparatus of the present invention. FIG. 6 shows an example of the processing flow of the specific direction sound pickup apparatus of the present invention. Signals x _m (n) (m = 1, 2,..., M) received by the microphone array 11 composed of M (≧ 2) microphones are transmitted from the beam former unit 12-1. Input to Q beam former units 12-1 to 12-Q up to unit 12-Q. Here, n represents the sample number of the discrete time signal.

In the beam former units 12-1 to 12-Q, for example, a directional beam BM as shown in FIG. 7 is directed to any one of the _Q direction regions Θ _{1 to} Θ Q given in advance in FIG. A process of collecting sound by emphasizing the sound emitted in the corresponding direction area is performed, and the result is output (S12-1 to S12-Q). The output signals y ₁ (n), y ₂ (n),..., Y _Q (n) of the beam former units 12-1 to 12-Q are respectively input to the frequency domain transform units 13-1 to 13-Q. The The frequency domain transforming units 13-1 to 13-Q decompose the input signal into frames having a short time length (for example, about 256 samples when the sampling frequency is 16000 Hz), and perform discrete Fourier transform in each frame. The obtained Ω frequency components are output as output signals Y ₁ (ω, l), Y ₂ (ω, l),... Y _Q (ω, l) (S13-1 to S13-Q). The frequency domain transformed signal is input to the signal amount estimation unit 14 and the specific direction selection unit 15, respectively.

The signal amount estimation unit 14 obtains a power component of the sum of sound signals emitted from the sound sources in the respective direction regions Θ _{1 to} Θ _Q from the output signal power of the input beam former units 12-1 to 12 _-Q . A signal power vector X _est (ω, l) in which these are combined into one vector is output (S14).

The specific direction selection unit 15 selects the output of the beam former unit that directs the directional beam to the direction region to be emphasized, and outputs it as Y _S (ω, l) (S15).

The gain coefficient calculation unit 16 calculates the gain coefficient R (ω, l) from the input signal power vector X _est (ω, l) and outputs it (S16). The gain coefficient R (ω, l) is input to the multiplication unit 17. The multiplier 17 outputs the result of multiplying the input gain coefficient R (ω, l) and the output Y _S (ω, l) of the specific direction selector 15 for each component of the same frequency (S17). The output signal Y _SR (ω, l) of the multiplication unit 17 is input to the inverse frequency domain transform unit 18, and a signal y (n) restored to a time signal by performing inverse discrete Fourier transform is output (S18). This signal y (n) is a signal picked up by enhancing the desired sound by the apparatus of the present invention.

  Details of the beam former units 12-1 to 12-Q, the signal amount estimation unit 14, the specific direction selection unit 15, and the gain coefficient calculation unit 16 will be described in order below with reference to another drawing.

(Beam former part)
FIG. 8 shows one configuration of the beam former units 12-1 to 12-Q. Similar processing is performed in all beam former units. The input signal x _m (n) (m = 1, 2,..., M) is input to the filter processing units FC1 to FCM. The filter processing units FC1 to FCM output a signal x ′ _qm (n) obtained by substituting a filter coefficient W _qm (n) given in advance (determination method will be described later) into the convolution operation shown in Expression (5). To do.

各フィルタ処理部ＦＣ１〜ＦＣＭの出力信号は加算部ＡＤＤに入力される。加算部ＡＤＤでは入力信号を式（６）のように加算し、ビームフォーマー部の出力信号ｙ_ｑ（ｎ）（ｑ＝１…Ｑ）を得る。

The output signals of the filter processing units FC1 to FCM are input to the adding unit ADD. The adder ADD adds the input signals as shown in Expression (6) to obtain the output signal y _q (n) (q = 1... Q) of the beam former.

ここでフィルタ係数Ｗ_ｑｍ（ｎ）は、それぞれのビームフォーマー部１２−１〜１２−Ｑの指向特性Ｄ_ｑ（ω，θ）が、図４に示すあらかじめ与えられた第Ｑ方向領域Θ_Ｑで発せられる音を強調して受音し、それ以外の方向で発せられる音を抑圧するように設計される。

Here, the filter coefficient W _qm (n) indicates that the directivity characteristics D _q (ω, θ) of the respective beam former units 12-1 to 12-Q are given in the Q-direction region Θ _Q given in advance as shown in FIG. It is designed to receive sound with emphasis on the sound emitted from the, and to suppress sound emitted in other directions.

(Signal amount estimation unit)
FIG. 9 shows the configuration of the signal amount estimation unit 14. The frequency components Y ₁ (ω, l), Y ₂ (ω, l),..., Y _Q (ω, l) input to the signal amount estimation unit 14 are input to the power calculation units PW-1 to PW-Q, respectively. The signal power values | Y ₁ (ω, l) | ² , | Y ₂ (ω, l) | ² ,..., | Y _Q (ω, l) | ² are output and input to the region aggregation unit 14A. (SPA in FIG. 6). The area aggregating unit 14A obtains an average of power values of signals emitted from a predetermined set S of areas to be collected and an average power of signals emitted from a set N of areas to be suppressed, and an aggregate power obtained as a result thereof. The vector Y (ω, l) is output (S14A in FIG. 6).

ただし、Ｎ_Ｓは集合Ｓに含まれる領域の数、Ｎ_Ｎは集合Ｎに含まれる領域の数を示している。また、すべての方向領域（１〜Ｑ）を集合Ｓまたは集合Ｎに所属するようにあらかじめ定めておく。例えば、Ｑ＝４のとき、集合Ｓと集合ＮをＳ＝｛１，２｝、Ｎ＝｛３，４｝のように決めればよい。

However, N _S is the number of areas included in the set S, N _N indicates the number of areas included in the set N. Further, all the direction areas (1 to Q) are determined in advance so as to belong to the set S or the set N. For example, when Q = 4, the sets S and N may be determined as S = {1, 2} and N = {3, 4}.

The beamformer unit output power vector Y (ω, l) is input to the multiplication unit 14B. The power estimation matrix T ⁻¹ (ω), which is the other input of the multiplication unit 14B, is an output signal of the inverse matrix calculation unit 14C. The inverse matrix calculator 14C receives the aggregate gain matrix T (ω) defined by the equation (8) and outputs the inverse matrix T ⁻¹ (ω) (S14C in FIG. 6).

集約ゲイン行列Ｔの各要素は、図１０に示すように各ビームフォーマー部の各方向領域に対する指向特性の平均値から求められるパラメータであり、例えば、式（９）に示すよう指向特性の方向に関する平均値を用いる。

Each element of the aggregate gain matrix T is a parameter obtained from the average value of the directivity with respect to each direction area of each beamformer unit as shown in FIG. 10, for example, the direction of the directivity as shown in Expression (9). The average value for is used.

α_ｐｑはビームフォーマー部１２−ｐの第ｑ方向領域に対する指向特性の平均値である。なお、指向特性は、例えば非特許文献１に記載されている技術を用いてフィルタ係数Ｗ_ｍ（ｎ）より求めることができる。

α _pq is an average value of directivity with respect to the q-th direction region of the beam former unit 12-p. The directivity can be obtained from the filter coefficient W _m (n) using the technique described in Non-Patent Document 1, for example.

As shown in Expression (10), the multiplication unit 14B performs multiplication of the input beamformer unit output power vector Y (ω, l) and the power estimation matrix T ⁻¹ (ω) for each frequency component, and thus an estimated signal. The power vector X _est (ω, l) is output (S14B in FIG. 6).

X _est (ω, l) = T ⁻¹ (ω) Y (ω, l) (10)
The signal amount estimation unit 14 estimates the signal power (signal amount) by performing the aggregation of the direction areas described in the principle of the present invention.

(Specific direction selector)
FIG. 11 shows the configuration of the specific direction selection unit 15. In the specific direction selection unit 15, among the frequency components Y ₁ (ω, l) to Y _Q (ω, l) input from the frequency domain conversion units 13-1 to 13-Q, the q-th direction region to be emphasized (however, , Q is one corresponding to one selected from 1,..., Q), and is output as Y _S (ω, l).

Y _S (ω, l) = Y _q (ω, l) (11)
(Gain coefficient calculator)
FIG. 12 shows the configuration of the gain coefficient calculation unit 16. The estimated signal power vector X _est (ω, l) input from the signal amount estimation unit 14 is input to the vector element extraction unit 16A. As shown in Expression (12), the estimated signal power vector X _est (ω, l) is a first component of the sound collection region signal estimated power | S (ω, l) | ² of the input estimated signal power vector, The suppression region signal estimated power | N (ω, l) | ² of the input estimated signal power vector is set as the second component.

X _est (ω, l) = [| S (ω, l) | ² | N (ω, l) | ² ] ^T (12)
The vector element extraction unit 16A outputs the sound collection region signal estimation power | S (ω, l) | ² and the suppression region signal estimation power | N (ω, l) | ² and inputs them to the SN ratio estimation unit 16B. To do. The signal-to-noise ratio estimation unit 16B calculates and outputs a gain coefficient R (ω, l) that enhances the signal in the desired direction region using Expression (13).

ここで、αは利得係数Ｒ（ω，ｌ）によって所望方向領域の信号の強調を調整するパラメータであって、例えばα＝１／２とすればよい。

Here, α is a parameter for adjusting the enhancement of the signal in the desired direction region by the gain coefficient R (ω, l), and for example, α may be set to 1/2.

  As described above, according to the specific direction sound collecting apparatus of the present embodiment, the signal received by the microphone array 11 is received in order to improve the enhancement effect when the sound emitted from the sound source in the desired direction is emphasized. Using the gain coefficient (nonlinear filter coefficient) that estimates the power of the sound signal emitted from each sound source from the results of the plurality of beam former units 12-1 to 12-Q and emphasizes the signal in the sound collection region Emphasize the sound signal. Therefore, it is not necessary to increase the number of microphones or increase the size of the microphone array. In addition, the emphasis effect can be improved with a small system that is easy to install and transport in practice.

In addition, since the signal amount estimation unit 14 of the specific direction sound pickup apparatus of the present embodiment uses a two-dimensional aggregate power vector, an aggregate gain matrix obtained from the directivity characteristics of the beam former units 12-1 to 12-Q is also used. 2 rows and 2 columns. Therefore, the calculation amount of the entire process can be greatly reduced.
[Second Embodiment]
The specific direction sound collecting device of the second embodiment is obtained by changing the processing procedure in the signal amount estimating unit 14, the gain coefficient calculating unit 16, and the multiplying unit 17 of the specific direction sound collecting device of the first embodiment. FIG. 13 is a diagram illustrating a configuration example of the specific direction sound pickup device of the second embodiment. The difference from the first embodiment is that band division units 19-1 to 19-Q are provided after the frequency domain conversion units 13-1 to 13-Q, a signal amount estimation unit 14, a gain coefficient calculation unit 16, and a multiplication. Each processing of the unit 17 is performed for every Ω frequency bands, and a band synthesizing unit 21 is provided in the subsequent stage of the multiplying unit 17 in each frequency band, and the output from the multiplying unit 17 of each band is synthesized. Is a point. FIG. 14 shows the configuration of the band dividing unit, and FIG. 15 shows the configuration of the band synthesizing unit.

The aggregate gain matrix T _x (ω) of the signal amount estimation unit 14 of the same band component collection unit 20-x (where x is 1,..., Ω) of the present embodiment is determined as shown in Expression (14). Good.

ただし、Ｎ_ｘは、集約されたｘ番目の帯域に含まれる周波数ビンの数である。その他の部分は第１実施形態と同じである。

Here, N _x is the number of frequency bins included in the aggregated x th band. Other parts are the same as those in the first embodiment.

Since it is such a structure, the specific direction sound collection apparatus of 2nd Embodiment can also acquire the same effect as the specific direction sound collection apparatus of 1st Embodiment. Furthermore, since the specific direction sound pickup device of the second embodiment can perform calculation for every Ω frequency bands, there is also an effect of reducing the amount of calculation.
[Experimental example]
FIG. 16 shows the experimental results of the specific direction sound pickup device of the present invention. FIG. 16 shows the noise suppression amount in decibel values in an experiment in which the position of the desired sound source (female voice) is fixed at 0 degree and the position of the noise source (male voice) is changed in the direction of every 15 degrees shown in FIG. Is. In FIG. 16, the amount of noise suppression increases as it goes inside the polar coordinate system. Further, in this experiment, since the region to be collected is set to 0 degrees to 90 degrees, 270 degrees to 360 degrees, the other direction (90 degrees to 270 degrees) is the region to be suppressed. In this experiment, a microphone array composed of four unidirectional microphones arranged at each vertex of a square with a side of 24 cm was used.

  In the prior art, the noise suppression amount gradually increases as the distance from the desired sound source increases. However, in the method according to the present invention, the noise suppression amount is uniformly low in the region where the sound is to be collected and exceeds the boundary with the region where the noise is to be suppressed. And it is increasing rapidly. The noise suppression amount of the prior art is about 7 dB even in the largest direction, whereas the method according to the present invention realizes a noise suppression amount of 10 dB or more in most directions of the region to be suppressed. From this, it can be confirmed that the method according to the present invention uniformly obtains the sound of the region to be picked up, and has high noise suppression performance over the entire region to be suppressed as compared with the prior art.

  FIG. 17 shows a functional configuration example of a computer. Note that the sound collection device of the present invention causes the recording unit 2020 of the computer 2000 to read a program that causes the computer 2000 to operate as each component of the present invention and operate the processing unit 2010, the input unit 2030, the output unit 2040, and the like. This can be achieved. In addition, as a method of causing the computer to read, the program is recorded on a computer-readable recording medium, and the program recorded on the server or the like is read into the computer through a telecommunication line or the like. There is a method to make it.

The figure for demonstrating the sound collection method of the microphone array by a prior art. The block diagram for demonstrating the conventional specific direction sound-collecting apparatus. The figure for demonstrating the directional characteristic of the conventional specific direction sound-collecting apparatus. The figure which shows the example of arrangement | positioning of the microphone array of the specific direction sound collection device of this invention. The figure which shows the example of whole structure of the specific direction sound collection apparatus of 1st Embodiment. The figure which shows the example of the processing flow of the specific direction sound collection apparatus of 1st Embodiment. The figure for demonstrating the directivity of the beam former part used for this invention. The figure which shows the structure of a beam former part. The figure which shows the structure of a signal amount estimation part. The figure for demonstrating an example of the directional characteristic of the beam former part used for this invention. The figure which shows the structure of a specific direction selection part. The figure which shows the structure of a gain coefficient calculation part. The figure which shows the structural example of the specific direction sound collection apparatus of 2nd Embodiment. The figure which shows the structure of a band division part. The figure which shows the structure of a zone | band synthetic | combination part. The figure which shows the experimental result of the specific direction sound-collecting apparatus of this invention. The figure which shows the function structural example of a computer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Microphone array 12-1 to 12-Q Beam former part 13-1 to 13-Q Frequency domain conversion part 14 Signal amount estimation part 14A Area aggregation part 14B Multiplication part 14C Inverse matrix calculation part 15 Specific direction selection part 16 Gain coefficient Calculation unit 17 Multiplication unit 18 Inverse frequency domain conversion unit 19-1 to 19-Q Band division unit 20-1 to 20-Ω Same band component collection unit 21 Band synthesis unit

Claims (4)

A plurality of beamformer sections that emphasize and collect sound coming from angular regions in different directions using output signals of a microphone array configured with a plurality of microphones;
A plurality of frequency domain conversion units for converting each of the angle domain signals collected by the plurality of beamformer units into a frequency domain signal divided into a plurality of band components;
A specific direction selection unit that selects a specific direction frequency domain signal from frequency domain signals belonging to a plurality of angular domains in a desired direction among the frequency domain signals output by the plurality of frequency domain transform units;
An aggregate power vector whose elements are a signal amount that is an average of frequency domain signals in a plurality of angle regions in the desired direction and a signal amount that is an average of frequency domain signals in a plurality of angle regions other than the angle region in the desired direction. Area aggregation means to be obtained; parameters obtained from an average value of directivity characteristics of the plurality of angle areas in the desired direction obtained from the directivity characteristics of the beamformer unit; and directivity of a plurality of angle areas other than the angle area of the desired direction An inverse matrix computing means for obtaining an inverse matrix of an aggregate gain matrix having a parameter obtained from an average value of characteristics as an element; and multiplying the aggregate power vector by the inverse matrix to obtain signals of a plurality of angle regions in the desired direction. Sound collection area signal estimation power, which is an estimated value of power, and suppression area signal estimation, which is an estimate of the power of signals in a plurality of angle areas other than the angle area in the desired direction A signal estimation unit and a multiplication means for obtaining an estimated signal power vector and a word as elements,
A gain coefficient calculation unit for calculating a gain coefficient for each frequency band from the sound collection area signal estimation power and the suppression area signal estimation power ;
A multiplier that multiplies the signal amount in each corresponding frequency band of the specific direction frequency domain signal by the gain coefficient calculated by the gain coefficient calculator;
A specific direction sound pickup device. A plurality of beamformer processing steps for enhancing and collecting sounds arriving from angular regions in different directions using output signals of a microphone array configured with a plurality of microphones;
A plurality of frequency domain conversion steps for converting each of the angle domain signals collected in the plurality of beamformer processing steps into a frequency domain signal divided into a plurality of band components;
A specific direction selection step of selecting a specific direction frequency domain signal from frequency domain signals belonging to a plurality of angle domains in a desired direction among frequency domain signals output by the plurality of frequency domain transformation steps;
An aggregate power vector whose elements are a signal amount that is an average of frequency domain signals in a plurality of angle regions in the desired direction and a signal amount that is an average of frequency domain signals in a plurality of angle regions other than the angle region in the desired direction. Parameters of directivity characteristics of a plurality of angle regions in the desired direction and parameters of directivity characteristics of a plurality of angle regions other than the angle region of the desired direction obtained from the directivity characteristics of the region aggregation sub-step to be obtained and the beamformer processing step And an inverse matrix calculation sub-step for obtaining an inverse matrix of an aggregate gain matrix having the element as an element, and multiplying the aggregate power vector by the inverse matrix to obtain an estimate of power of signals in a plurality of angle regions in the desired direction. Elements of sound region signal estimation power and suppression region signal estimation power that is an estimated value of the power of signals in a plurality of angle regions other than the angle region of the desired direction A signal estimation step and a multiplier sub-step of obtaining an estimated signal power vectors,
A gain coefficient calculation step of calculating a gain coefficient for each frequency band from the sound collection area signal estimation power and the suppression area signal estimation power ;
A multiplication step of multiplying the signal amount of each corresponding frequency band of the specific direction frequency domain signal by the gain factor calculated by the gain factor calculation step;
A specific direction sound collection method.   A specific direction sound collecting program for operating a computer as the specific direction sound collecting device according to claim 1.   A computer-readable recording medium on which the sound collecting program for a specific direction according to claim 3 is recorded.

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