JP3379083B2

JP3379083B2 - Sound source zone detection method, its device, and its program recording medium

Info

Publication number: JP3379083B2
Application number: JP24515797A
Authority: JP
Inventors: 真理子青木; 茂明青木; 弘行松井
Original assignee: Nippon Telegraph and Telephone Corp; NTT Inc USA
Current assignee: NTT Inc; NTT Inc USA
Priority date: 1997-03-13
Filing date: 1997-09-10
Publication date: 2003-02-17
Anticipated expiration: 2017-09-10
Also published as: JPH10313500A

Description

Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】この発明は、複数の音源が配
された空間において、発音している音源、例えば発話し
ている人間が位置しているゾーン（領域）を検出する方
法、その装置とコンピュータで実行するためのプログラ
ムを記録した記録媒体に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a sound source producing sound, for example, a zone (area) in which a person speaking is located in a space where a plurality of sound sources are arranged, and an apparatus therefor. The present invention relates to a recording medium recording a program to be executed by a computer.

【０００２】[0002]

【従来の技術】複数の音源が配置された空間において、
発音、例えば発話している音源が所在するゾ−ンを検出
する方法として、従来から、複数のマイクロホンを配置
し、音源から各マイクロホンに到達する音響信号の到達
時間差から音源の位置を検出する方法がある。この方法
は、マイクロホンの出力音声信号の相互相関のピ−ク値
を利用することにより、各マイクロホンへの音響信号の
到達時間差を検出して音源の位置を検出するものであ
る。2. Description of the Related Art In a space where a plurality of sound sources are arranged,
As a method of detecting a sound, for example, a zone where a sound source that is speaking is located, a method of arranging a plurality of microphones and detecting the position of the sound source from the difference in arrival time of acoustic signals that reach the microphones from the sound source There is. This method detects the position of a sound source by detecting the arrival time difference of the acoustic signal to each microphone by using the peak value of the cross-correlation of the output audio signal of the microphone.

【０００３】ところが、この検出方法では、次のような
問題点があった。まず、相互相関関数の計算は、読み込
んだデ−タ長の２倍の長さの和積演算を要するため、長
い計算時間が必要となることである。次に、相互相関の
ピ−クを検出するためにはヒストグラムをとる方法が有
効であるが、時間軸上でヒストグラムをとると遅延を生
じる。そこで、遅延を生じさせずにヒストグラムをとる
方法として、例えば信号を帯域分割して、全帯域にわた
ってヒストグラムをとることが考えられる。しかし、相
互相関関数はある程度以上の広帯域信号を用いる必要が
あるため、実際には高々数分割のオーダでしか帯域分割
できない。したがって、ある程度の長さの信号を用い、
時間軸上でヒストグラムをとる必要があるが、この手法
では、実時間で音源位置を検出することは困難であっ
た。However, this detection method has the following problems. First, the calculation of the cross-correlation function requires a sum-product operation with a length twice as long as the read data length, and thus requires a long calculation time. Next, a method of taking a histogram is effective for detecting a peak of cross-correlation, but taking a histogram on the time axis causes a delay. Therefore, as a method of obtaining a histogram without causing a delay, for example, it is possible to divide a signal into bands and obtain a histogram over the entire band. However, since the cross-correlation function needs to use a wideband signal of a certain level or more, it can be band-divided only on the order of at most several divisions. Therefore, using a signal of a certain length,
Although it is necessary to take a histogram on the time axis, it was difficult to detect the sound source position in real time by this method.

【０００４】また音源方向の推定に、２つのマイクロホ
ンの出力をそれぞれ複数の帯域に分割して処理する方法
が日本国特開平５−８７９０３号公報で提案されてい
る。この方法は分割された各対応帯域の信号の相互相関
を演算する必要があり、従って、処理時間が長いという
欠点がある。A method for dividing the outputs of two microphones into a plurality of bands and processing them for the estimation of the sound source direction has been proposed in Japanese Unexamined Patent Publication No. 5-87903. This method has a disadvantage in that it is necessary to calculate the cross-correlation of the divided signals in the corresponding bands, and thus the processing time is long.

【０００５】[0005]

【発明が解決しようとする手段】この発明の目的は実時
間で検出できる音源ゾーン検出方法、装置、プログラム
記録媒体を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a sound source zone detection method, device and program recording medium which can be detected in real time.

【０００６】[0006]

【課題を解決するための手段】この発明によれば、複数
のマイクロホンを互いに離して設け、これらマイクロホ
ンからの各チャネル信号を、複数の周波数帯域に分割す
ると共に、各分割されたチャネル信号の同一帯域ごと
に、複数のマイクロホンの位置に起因して変化する、マ
イクロホンに到達する音響信号のパラメータとしてレベ
ル、又は到達時間差の値をそれぞれ検出する。この場
合、分割された各帯域には、主たる成分は１つの音源か
らの信号成分のみとなる程度に小さく分割する。これら
検出されたパラメータ値を同一帯域について比較し、そ
の極限値のチャネル、つまりレベルが最も大きなチャネ
ルや到達時間が最も速いチャネルを決定し、各チャネル
ごとに極限値の帯域の数を求め、その極限値の帯域数が
最大のチャネル、又は基準値を越えたチャネルのマイク
ロホンが受けもつゾーンを、音源が位置している領域
（音源ゾーン）とする。According to the present invention, a plurality of microphones are provided separately from each other, each channel signal from these microphones is divided into a plurality of frequency bands, and each divided channel signal is the same. For each band, a level or an arrival time difference value is detected as a parameter of an acoustic signal reaching the microphone, which changes due to the positions of the plurality of microphones. In this case, each of the divided bands is divided into small parts such that the main component is only the signal component from one sound source. These detected parameter values are compared for the same band, the channel of the limit value, that is, the channel with the largest level or the channel with the fastest arrival time is determined, and the number of the limit value bands is calculated for each channel. The zone in which the microphone of the channel having the maximum number of bands of the limit value or the channel of which the reference value exceeds the reference value is taken as the region where the sound source is located (sound source zone).

【０００７】[0007]

【発明の実施の形態】この発明の実施例を図面を参照し
て説明する。図１に示すように、互いに離された複数の
マイクロホンとしてこの例ではマイクロホンＭ１，Ｍ
２，Ｍ３が、例えば１辺が２０ｃｍの正三角形の各頂点
の位置に配置されている。マイクロホンＭ１〜Ｍ３の指
向特性に基づいて空間が分割して設定され、その各分割
された空間を音源ゾーンと呼ぶ。全てのマイクロホンＭ
１〜Ｍ３が無指向で同じ特性を有する場合には、例えば
図２に示すように、ゾーンＺ１〜Ｚ６のように６個に分
割される。つまり、各マイクロホンＭ１，Ｍ２，Ｍ３
と、その中心点Ｃp をそれぞれ通る直線により、中心点
Ｃp を中心に等角間隔で６分割された６つのゾーンＺ１
〜Ｚ６が形成される。音源ＡはゾーンＺ３に、音源Ｂは
ゾーンＺ４に位置している。つまり、１個の音源ゾーン
には１個の音源が属するように、マイクロホンＭ１〜Ｍ
３の配置や特性に基づいて各音源ゾーンを決定する。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the microphones M1 and M in this example are a plurality of microphones that are separated from each other.
2, M3 are arranged at the positions of the vertices of an equilateral triangle having a side of 20 cm, for example. A space is divided and set based on the directional characteristics of the microphones M1 to M3, and each divided space is called a sound source zone. All microphones M
When 1 to M3 are omnidirectional and have the same characteristic, they are divided into six zones Z1 to Z6 as shown in FIG. 2, for example. That is, each microphone M1, M2, M3
And six zones Z1 divided into six at equal angular intervals by the straight line passing through the center point Cp.
~ Z6 is formed. The sound source A is located in the zone Z3 and the sound source B is located in the zone Z4. That is, the microphones M1 to M are arranged so that one sound source belongs to one sound source zone.
Each sound source zone is determined based on the arrangement and characteristics of No. 3.

【０００８】図１において、帯域分割部４１は、マイク
ロホンＭ１で収音した第１チャネルの音響信号Ｓ１をｎ
個の周波数帯域信号Ｓ１（ｆ１）〜Ｓ１（ｆｎ）に分割
し、帯域分割部４２でマイクロホンＭ２で収音した第２
チャネルの音響信号Ｓ２をｎ個の周波数帯域信号Ｓ２
（ｆ１）〜Ｓ２（ｆｎ）に分割し、帯域分割部４３は、
マイクロホンＭ３で収音した第３チャネルの音響信号Ｓ
３をｎ個の周波数帯域信号Ｓ３（ｆ１）〜Ｓ３（ｆｎ）
に分割する。これら各帯域ｆ１〜ｆｎは帯域分割部４１
〜４３で共通であり、このような帯域分割は離散的フー
リエ変換器を利用して行うことができる。つまり各チャ
ネルの音響信号を離散的フーリエ変換して周波数スペク
トルを求め、この周波数スペクトルを、分割された各帯
域に主として含まれるスペクトルが１つの音源からの信
号成分となる程度に狭い帯域、音源信号が音声の場合は
１０〜２０Ｈｚ程度帯域に分割する。In FIG. 1, the band division unit 41 outputs the sound signal S1 of the first channel picked up by the microphone M1 to n.
The second frequency band signals S1 (f1) to S1 (fn) divided by the microphone M2 by the band dividing unit 42.
The acoustic signal S2 of the channel is converted into n frequency band signals S2
(F1) to S2 (fn), and the band division unit 43
Sound signal S of the third channel picked up by the microphone M3
3 to n frequency band signals S3 (f1) to S3 (fn)
Split into. Each of these bands f1 to fn is divided into a band dividing unit 41.
~ 43, and such band division can be performed using a discrete Fourier transformer. That is, the frequency spectrum is obtained by performing a discrete Fourier transform on the acoustic signal of each channel, and the frequency spectrum is narrowed to the extent that the spectrum mainly contained in each of the divided bands becomes a signal component from one sound source. If is a voice, it is divided into bands of about 10 to 20 Hz.

【０００９】帯域別レベル（パワー）検出部５１では帯
域分割部４１で得られた各帯域の信号Ｓ１（ｆ１）〜Ｓ
１（ｆｎ）のレベル（パワー）信号Ｐ（Ｓ１ｆ１）〜Ｐ
（Ｓ１ｆｎ）が検出され、同様に帯域別レベル検出部５
２，５３ではそれぞれ帯域分割部４２，４３で得られた
各帯域信号Ｓ２（ｆ１）〜Ｓ２（ｆｎ），Ｓ３（ｆ１）
〜Ｓ３（ｆｎ）の各レベル信号Ｐ（Ｓ２ｆ１）〜Ｐ（Ｓ
２ｆｎ），Ｐ（Ｓ３ｆ１）〜Ｐ（Ｓ３ｆｎ）がそれぞれ
検出される。これら帯域別レベル検出もフーリエ変換器
で実現できる。つまり各チャネル信号を離散的フーリエ
変換によりスペクトルに分解し、その各スペクトルの電
力を求めればよい。従って、各チャネル信号について、
まずパワースペクトルを求め、そのパワースペクトルを
帯域分割してもよい。各マイクロホンＭ１〜Ｍ３の各チ
ャネル信号を、帯域分割・帯域別レベル検出部４００で
各帯域に分割すると共にそのレベル（パワー）を出力す
ることになる。In the band level (power) detecting section 51, the signals S1 (f1) to S of the respective bands obtained by the band dividing section 41 are obtained.
1 (fn) level (power) signals P (S1f1) to P
(S1fn) is detected, and similarly, the band-specific level detection unit 5
2 and 53, the band signals S2 (f1) to S2 (fn) and S3 (f1) obtained by the band division units 42 and 43, respectively.
-S3 (fn) level signals P (S2f1) -P (S
2fn) and P (S3f1) to P (S3fn) are respectively detected. The level detection for each band can also be realized by the Fourier transformer. That is, each channel signal may be decomposed into spectra by discrete Fourier transform, and the power of each spectrum may be obtained. Therefore, for each channel signal,
First, a power spectrum may be obtained, and the power spectrum may be band-divided. Each channel signal of each microphone M1 to M3 is divided into each band by the band division / band level detection unit 400, and the level (power) is output.

【００１０】音源ゾーン判定部７０では、コンピュータ
処理により、音響を発している音源が位置するゾーン
（音源ゾーン）を判定する。まず、帯域別レベル検出部
５０により得られた帯域別レベルＰ（Ｓ１ｆ１）〜Ｐ
（Ｓ１ｆｎ），Ｐ（Ｓ２ｆ１）〜Ｐ（Ｓ２ｆｎ），Ｐ
（Ｓ３ｆ１）〜Ｐ（Ｓ３ｆｎ）を、同一の帯域の信号に
ついて相互に比較する。そして各帯域ｆ１〜ｆｎ毎に、
最も大きなレベルのチャネルを特定する。The sound source zone determination unit 70 determines the zone (sound source zone) in which the sound source emitting sound is located by computer processing. First, the band-specific levels P (S1f1) to P obtained by the band-specific level detection unit 50
(S1fn), P (S2f1) to P (S2fn), P
(S3f1) to P (S3fn) are compared with each other for signals in the same band. And for each band f1 to fn,
Identify the highest level channel.

【００１１】帯域分割の数ｎを所定数以上にすることに
より、前述したように、１つの帯域には１個の音源の音
響信号しか含まれないと見なせるようにすることができ
るので、同一帯域ｆｉ（ｉ＝１，２，…，ｎ）のレベル
Ｐ（Ｓ１ｆｉ），Ｐ（Ｓ２ｆｉ），Ｐ（Ｓ３ｆｉ）は、
同一音源からの音響のレベルと見なすことができる。よ
って、第１〜第３チャネルについて同一の帯域のレベル
Ｐ（Ｓ１ｆｉ），Ｐ（Ｓ２ｆｉ），Ｐ（Ｓ３ｆｉ）に差
があるときは、音源に最も近いマイクロホンのチャネル
の帯域のレベルが最も大きくなる。By setting the number of band divisions n to be a predetermined number or more, it can be considered that one band includes only the acoustic signal of one sound source, as described above. The levels P (S1fi), P (S2fi), P (S3fi) of fi (i = 1, 2, ..., N) are
It can be regarded as the level of sound from the same sound source. Therefore, when the levels P (S1fi), P (S2fi), P (S3fi) of the same band for the first to third channels are different, the level of the band of the channel of the microphone closest to the sound source becomes the highest. .

【００１２】前記処理の結果、各帯域ｆ１〜ｆｎについ
て、最もレベルの大きなチャネルがそれぞれ割り当てら
れる。ｎ個の帯域中で第１〜第３各チャネルについて、
最もレベルが大きな帯域の合計数χ１，χ２，χ３を算
出する。この合計数の値が大きいチャネルのマイクロホ
ンほど、音源に近いとみなすことができる。合計数値が
例えば９０ｎ／１００以上程度であればそのチャネルの
マイクロホンに音源が近いと判定することができる。し
かし、最もレベルが大きい帯域の合計数が５３ｎ／１０
０、次に大きい合計数が４９ｎ／１００の場合はそのそ
れぞれのチャネルと対応マイクロホンの何れに音源が近
いか明確ではない。従って当該合計数が最大で、かつ予
め設定した基準値Ｔｈ１、例えばｎ／３程度を越えたと
き、当該合計数と対応するチャネルのマイクロホンにそ
の音源が最も近いと判定する。As a result of the above process, the highest level channel is assigned to each of the bands f1 to fn. For each of the first to third channels in the n bands,
The total number χ1, χ2, χ3 of the band with the highest level is calculated. It can be considered that the microphone of the channel having the larger value of the total number is closer to the sound source. If the total numerical value is, for example, about 90n / 100 or more, it can be determined that the sound source is close to the microphone of the channel. However, the total number of bands with the highest level is 53n / 10.
When the total number is 0, and the next largest total number is 49n / 100, it is not clear which of the respective channels and the corresponding microphone the sound source is close to. Therefore, when the total number is maximum and exceeds a preset reference value Th1, for example, about n / 3, it is determined that the sound source is closest to the microphone of the channel corresponding to the total number.

【００１３】いま、図２に示すように音源Ａ，Ｂが位置
している時マイクロホンＭ１〜Ｍ３を図に示したように
配置し、ゾーンＺ１〜Ｚ６を決定したとする。つまりこ
の例では音源ＡとＢが別個のゾーンＺ３，Ｚ４にそれぞ
れ位置しているとする。この時、音源Ａのマイクロホン
Ｍ１〜Ｍ３に対する各距離ＳＡ１，ＳＡ２，ＳＡ３は、
ＳＡ２＜ＳＡ３＜ＳＡ１となる。また、音源Ｂの各マイ
クロホンＭ１〜Ｍ３に対する距離ＳＢ１，ＳＢ２，ＳＢ
３は、ＳＢ３＜ＳＢ２＜ＳＢ１となる。Now, suppose that the microphones M1 to M3 are arranged as shown in FIG. 2 when the sound sources A and B are located as shown in FIG. 2 and the zones Z1 to Z6 are determined. That is, in this example, it is assumed that the sound sources A and B are located in the separate zones Z3 and Z4, respectively. At this time, the distances SA1, SA2, SA3 of the sound source A to the microphones M1 to M3 are
SA2 <SA3 <SA1. Further, the distances SB1, SB2 and SB of the sound source B to the microphones M1 to M3 are
3 is SB3 <SB2 <SB1.

【００１４】音源Ａのみが発音しているときは、その音
響信号のすべての帯域の周波数成分がマイクロホンＭ２
へ一番大きな音圧レベル（パワー）で到達するので、こ
のマイクロホンＭ２のチャネルの合計帯域数χ２が最も
多くなる。また、音源Ｂのみが発音しているときは、そ
の音響信号のすべての帯域の周波数成分がマイクロホン
Ｍ３へ一番大きな音圧レベルで到達するので、このマイ
クロホンＭ３のチャネルの合計帯域数χ３が最も多くな
る。When only the sound source A is producing sound, the frequency components of all the bands of the acoustic signal are the microphone M2.
Since the maximum sound pressure level (power) is reached, the total number of bands χ2 of the channels of the microphone M2 is the largest. Further, when only the sound source B is producing sound, the frequency components of all the bands of the acoustic signal reach the microphone M3 with the largest sound pressure level, and therefore the total number of bands χ3 of the channels of this microphone M3 is the largest. Will increase.

【００１５】さらに、音源Ａ，Ｂが共に発音している場
合には、音響信号が最も大きな音圧レベルで到達する帯
域数がマイクロホンＭ２とＭ３で拮抗する。したがっ
て、基準値Ｔｈ２、例えば２ｎ／３により、音響信号が
あるマイクロホンへ最も大きな音圧レベルで到達する合
計帯域数が、当該基準値Ｔｈ２を越えた場合、当該マイ
クロホンが司るゾーンに音源が存在すると判定すること
により、発音している音源ゾーンを検出することができ
る。Further, when the sound sources A and B are both sounding, the number of bands reached by the acoustic signal at the highest sound pressure level is balanced by the microphones M2 and M3. Therefore, when the total number of bands that reach the microphone having the acoustic signal at the highest sound pressure level by the reference value Th2, for example, 2n / 3, exceeds the reference value Th2, it is determined that the sound source exists in the zone controlled by the microphone. By making a determination, the sound source zone that is producing a sound can be detected.

【００１６】上記の例では、音源Ａのみが発音している
ときは、χ２のみが基準値Ｔｈ２を越えて、発音してい
る音源が存在するのはマイクロホンＭ２が司るゾーンＺ
２及びＺ３であると検出される。また、音源Ｂのみが発
音しているときは、χ３のみが基準値Ｔｈ２を越えて、
発音している音源が存在するのは、マイクロホンＭ３が
司るゾーンＺ４及びＺ５であると検出される。In the above example, when only the sound source A is producing sound, only χ2 exceeds the reference value Th2, and the sound source producing sound exists in the zone Z controlled by the microphone M2.
2 and Z3. When only the sound source B is sounding, only χ3 exceeds the reference value Th2,
It is detected that the sound source producing sound is present in the zones Z4 and Z5 controlled by the microphone M3.

【００１７】更に音源Ａのみが発音している状態ではχ
２のみがＴｈ２を越え、かつ他チャネルのχ１とχ３を
比較すると、χ１＜χ３となっているから、ゾーンＺ３
に音源があると、１つが受けもつゾーンよりも、狭い確
度で検出できる。同様に、音源Ｂのみが発音している状
態ではχ３がＴｈ２を越え、かつχ１とχ２を比較する
とχ１＜χ２となり、ゾーンＺ４に音源があると検出さ
れる。更に音源Ａ，Ｂが共に発音している状態では、ゾ
ーンＺ３とＺ４に音源があると検出される。Further, when only the sound source A is sounding, χ
When only 2 exceeds Th2, and when χ1 and χ3 of other channels are compared, χ1 <χ3 is established, so zone Z3
If there is a sound source at, it can be detected with a narrower accuracy than the zone covered by one. Similarly, when only sound source B is sounding, χ3 exceeds Th2, and when χ1 and χ2 are compared, χ1 <χ2, and it is detected that there is a sound source in zone Z4. Further, when both sound sources A and B are sounding, it is detected that there are sound sources in zones Z3 and Z4.

【００１８】なお、以上の例では、ゾーンをＺ１〜Ｚ６
の６つに分けたが、図３に示すように、中心点Ｃp から
各マイクロホン間の中点を通る点線により３つのゾーン
Ｚ１〜Ｚ３に分けても同様に音源状態を判定できる。こ
の場合は、例えば、音源Ａのみが発音している場合は、
マイクロホンＭ２のチャネルの帯域数χ２が最も大きく
なるので、そのマイクロホンＭ２の司るゾーンＺ２に音
源があると判定される。また、音源Ｂのみが発音してい
る場合はχ３が最も大きくなり、ゾーンＺ３に音源があ
ると判定される。In the above example, the zones are Z1 to Z6.
However, as shown in FIG. 3, the sound source state can be similarly determined by dividing into three zones Z1 to Z3 by a dotted line passing from the center point Cp to the midpoint between the microphones. In this case, for example, when only the sound source A is sounding,
Since the number of bands χ2 of the channel of the microphone M2 is the largest, it is determined that there is a sound source in the zone Z2 controlled by the microphone M2. Further, when only the sound source B is sounding, χ3 becomes the largest and it is determined that there is a sound source in the zone Z3.

【００１９】上述では、到達音響信号のパラメータ中の
マイクロホンＭ１〜Ｍ３の位置に応じて、変化するもの
としてレベルを用いたが、到達時間差を用いることもで
きる。この例を図４に、図１と対応する部分に同一符号
を付けて示す。この実施例では帯域分割部４１で得られ
た各帯域ｆ１〜ｆｎの信号Ｓ１（ｆ１）〜Ｓ１（ｆｎ）
から到達時間差信号Ａｎ（Ｓ１ｆ１）〜Ａｎ（Ｓ１ｆ
ｎ）が帯域別時間差検出部１０１で検出され、同様に帯
域分割部４２，４３でそれぞれ得られた各帯域の信号Ｓ
２（ｆ１）〜Ｓ２（ｆｎ），Ｓ３（ｆ１）〜Ｓ３（ｆ
ｎ）からそれぞれ到達時間差信号Ａｎ（Ｓ２ｆ１）〜Ａ
ｎ（Ｓ２ｆｎ），Ａｎ（Ｓ３ｆ１）〜Ａｎ（Ｓ３ｆｎ）
が帯域別時間差検出部１０２，１０３で検出される。In the above description, the level is used as a variable depending on the positions of the microphones M1 to M3 in the parameters of the arrival acoustic signal, but the arrival time difference may be used. This example is shown in FIG. 4 with the same reference numerals attached to the portions corresponding to FIG. In this embodiment, the signals S1 (f1) to S1 (fn) of the bands f1 to fn obtained by the band division unit 41 are obtained.
From arrival time difference signals An (S1f1) to An (S1f
n) is detected by the band-based time difference detection unit 101, and similarly, the signals S of the respective bands obtained by the band division units 42 and 43, respectively.
2 (f1) to S2 (fn), S3 (f1) to S3 (f
n) from the arrival time difference signals An (S2f1) to A, respectively.
n (S2fn), An (S3f1) to An (S3fn)
Is detected by the band-based time difference detection units 102 and 103.

【００２０】これらの到達時間差信号を得る処理は、例
えば、フーリエ変換により各帯域の信号の位相（あるい
は群遅延）を算出し、同一の帯域ｆｉの信号Ｓ１（ｆ
ｉ），Ｓ２（ｆｉ），Ｓ３（ｆｉ）（ｉ＝１，２，…，
ｎ）の位相を相互に比較することで、同一音源信号の到
達時間差と対応した信号を得ることができる。この場合
も帯域分割部４０での分割は、１つの帯域には１つの音
源信号成分しか存在しないとみなせる程度に小さく行
う。In the process for obtaining these arrival time difference signals, for example, the phase (or group delay) of the signals in each band is calculated by Fourier transform, and the signal S1 (f in the same band fi is calculated.
i), S2 (fi), S3 (fi) (i = 1, 2, ...,
By comparing the phases of n) with each other, it is possible to obtain a signal corresponding to the arrival time difference of the same sound source signal. In this case as well, the division by the band division unit 40 is made so small that only one sound source signal component is present in one band.

【００２１】この到達時間差の表現方法は、例えば、マ
イクロホンＭ１〜Ｍ３のいずれかを基準にしてその基準
マイクロホンに対する到達時間差を０に設定しておけ
ば、他のマイクロホンに対する到達時間差はその基準マ
イクロホンに対して速く到達したか遅く到達したかで判
定できるので、正又は負の極性を付した数値で表すこと
ができる。この場合、基準マイクロホンを例えばＭ１と
すると、到達時間差信号Ａｎ（Ｓ１ｆ１）〜Ａｎ（Ｓ１
ｆｎ）は全て０となる。In this method of expressing the arrival time difference, for example, if one of the microphones M1 to M3 is set as a reference and the arrival time difference for the reference microphone is set to 0, the arrival time difference for other microphones is set to the reference microphone. On the other hand, since it can be determined whether the arrival is fast or slow, it can be represented by a numerical value with a positive or negative polarity. In this case, assuming that the reference microphone is M1, for example, the arrival time difference signals An (S1f1) to An (S1
fn) is all 0.

【００２２】音源ゾーン判定部１１０では、コンピュー
タ処理により発音している音源ゾーンを判定する。ま
ず、帯域別時間差検出部１００により得られる到達時間
差信号Ａｎ（Ｓ１ｆ１）〜Ａｎ（Ｓ１ｆｎ），Ａｎ（Ｓ
２ｆ１）〜Ａｎ（Ｓ２ｆｎ），Ａｎ（Ｓ３ｆ１）〜Ａｎ
（Ｓ３ｆｎ）を、同一の帯域の信号について相互に比較
する。これにより各帯域ｆ１〜ｆｎ毎に、最も信号が速
く到達するチャネルを決定する。The sound source zone determination unit 110 determines the sound source zone which is being sounded by computer processing. First, the arrival time difference signals An (S1f1) to An (S1fn), An (S
2f1) to An (S2fn), An (S3f1) to An
(S3fn) are compared with each other for signals in the same band. As a result, the channel through which the signal arrives fastest is determined for each of the bands f1 to fn.

【００２３】そこで、各チャネルについて信号が最も速
く到達すると判定された帯域の合計数を算出して、それ
をチャネル間で比較する。この結果、この合計帯域数の
値が大きいチャネルのマイクロホンほど、音源に近いと
みなすことができる。そして、あるチャネルについて、
当該合計帯域数が予め設定した基準値Ｔｈ２を越えたと
き、当該のチャネルのマイクロホンが司るゾーンに音源
があると判定する。Therefore, the total number of bands for which it is determined that the signal arrives the fastest for each channel is calculated and compared between the channels. As a result, it can be considered that the microphone of the channel having the larger value of the total number of bands is closer to the sound source. And for a channel,
When the total number of bands exceeds a preset reference value Th2, it is determined that there is a sound source in the zone controlled by the microphone of the channel.

【００２４】いま図２に示したように音源Ａ，Ｂに対
し、マイクロホンＭ１〜Ｍ３が配置されていたとする。
またマイクロホンＭ１のチャネルに対する前記した合計
帯域数をχ１、マイクロホンＭ２，Ｍ３の各チャネルに
対する合計帯域数をそれぞれχ２，χ３とする。音源Ａ
のみが発音しているときは、その音源信号のすべての帯
域の周波数成分がマイクロホンＭ２へ一番速く到達する
ので、このマイクロホンＭ２のチャネルの合計帯域数χ
２が最も多くなる。また、音源Ｂのみが発音していると
きは、その音源信号のすべての帯域の周波数成分がマイ
クロホンＭ３へ一番速く到達するので、このマイクロホ
ンＭ３のチャネルの合計帯域数χ３が最も多くなる。Now, suppose that the microphones M1 to M3 are arranged for the sound sources A and B as shown in FIG.
The total number of bands for the channels of the microphone M1 is χ1, and the total number of bands for the channels of the microphones M2 and M3 is χ2, χ3, respectively. Sound source A
When only one is sounding, the frequency components of all the bands of the sound source signal reach the microphone M2 fastest, so the total number of bands χ of the channels of this microphone M2.
2 is the most. Further, when only the sound source B is producing sound, the frequency components of all the bands of the sound source signal reach the microphone M3 fastest, so that the total number of bands χ3 of the channels of the microphone M3 becomes the largest.

【００２５】さらに、音源Ａ，Ｂが共に発音している場
合には、音源信号が最も速く到達する帯域数がマイクロ
ホンＭ２とＭ３で拮抗する。したがって、前記した基準
値Ｔｈ２により、音源信号があるマイクロホンへ最も速
く到達する合計帯域数が、当該設定値Ｔｈ２を越えた場
合、当該マイクロホンが司るゾーンに音源が存在してい
ると判定する。Further, when the sound sources A and B are both sounding, the number of bands in which the sound source signal reaches the earliest is equal in the microphones M2 and M3. Therefore, when the total number of bands that reaches the microphone with the sound source signal fastest with the reference value Th2 exceeds the set value Th2, it is determined that the sound source exists in the zone controlled by the microphone.

【００２６】上記の例では、音源Ａのみが発音している
ときは、χ２のみが基準値Ｔｈ２を越えて、音響を発生
している音源が存在するのはマイクロホンＭ２が司るゾ
ーンＺ２及びＺ３であると検出される。また、音源Ｂの
みが発音しているときは、χ３のみが基準値Ｔｈ２を越
え、音を発している音源が存在するのは、マイクロホン
Ｍ３が司るゾーンＺ４及びＺ５であると検出される。In the above example, when only the sound source A is producing sound, only χ2 exceeds the reference value Th2, and the sound source producing sound exists in the zones Z2 and Z3 controlled by the microphone M2. Detected as present. Further, when only the sound source B is producing sound, only χ3 exceeds the reference value Th2, and it is detected that the sound source producing sound exists in the zones Z4 and Z5 controlled by the microphone M3.

【００２７】この場合も、音源Ａのみが発音している時
は、χ２がＴｈ２を越え、他のχ１とχ３を比較すると
χ１＜χ３となり、音源はゾーンＺ３にあると判定でき
る。同様に音源Ｂのみが発音している時は、χ３＞Ｔｈ
２、かつχ１＜χ２となり、ゾーンＺ４に音源があると
判定できる。更に音源Ａ，Ｂが共に発音している状態で
はゾーンＺ３とＺ４に音源があると検出される。更に、
レベル検出の場合と同様に、合計帯域数が最大のチャネ
ルのマイクロホンのゾーンを音源ゾーンとし、この場
合、その帯域数がＴｈ１以上を条件とすることもでき
る。また図３に示したようにゾーンを３つに別けて、音
源ゾーンの検出を行うこともレベルを用いた場合と同様
に音源ゾーンを検出することができる。Also in this case, when only the sound source A is sounding, χ2 exceeds Th2, and when χ3 is compared with other χ1, χ1 <χ3, and it can be determined that the sound source is in the zone Z3. Similarly, when only sound source B is sounding, χ3> Th
2, and χ1 <χ2, and it can be determined that there is a sound source in zone Z4. Further, when both sound sources A and B are sounding, it is detected that there are sound sources in zones Z3 and Z4. Furthermore,
As in the case of level detection, the microphone zone of the channel with the maximum total number of bands can be set as the sound source zone, and in this case, the number of bands can be set to Th1 or more. Further, as shown in FIG. 3, the sound source zone can be detected by dividing the zone into three zones and detecting the sound source zone as in the case of using the level.

【００２８】マイクロホンの数は３個に限らず、２個以
上あればよい、つまり、存在し得る音源の数がＮ個なら
マイクロホンもＮ個以上あればよい。音源の検出位置精
度を高くする場合は、マイクロホンの数をなるべく多く
する。上述した、音源ゾーン検出の処理手順の例を図５
に示す。簡単に説明すると、まずマイクロホンＭ１〜Ｍ
３からの各チャネル信号を取込み（Ｓ１）、各チャネル
信号をそれぞれ複数の帯域に分割し（Ｓ２）、これら各
分割された各帯域信号のレベル又は到達時間差を求める
（Ｓ３）、次に同一帯域について最大レベルのチャネル
又は最も速く到達したチャネルを決定し（Ｓ４）、各チ
ャネルについて最大レベルとなった帯域又は最も速く到
達した帯域の数χ１，χ２，χ３，…を計数し（Ｓ
５）、これら計数値χ１，χ２，χ３，…の最大のもの
χ_Mを選択し（Ｓ６）、そのχ_Mと対応するチャネルＭ
のマイクロホンが受けもつゾーンに音源が位置すると判
定する（Ｓ７）。The number of microphones is not limited to three, but may be two or more, that is, if the number of sound sources that can exist is N, the number of microphones may be N or more. To increase the accuracy of the sound source detection position, increase the number of microphones as much as possible. An example of the processing procedure of the sound source zone detection described above is shown in FIG.
Shown in. To briefly explain, first, the microphones M1 to M
Each channel signal from S.3 is taken (S1), each channel signal is divided into a plurality of bands (S2), the level or arrival time difference of each of these divided band signals is obtained (S3), and then the same band is obtained. For each channel, the maximum level channel or the fastest arriving channel is determined (S4), and the number of the maximum level band or the fastest arriving band χ1, χ2, χ3, ... Is counted for each channel (S4).
5), the largest one of these count values χ1, χ2, χ3, ... χ _M is selected (S6), and the channel M corresponding to that χ _M is selected.
It is determined that the sound source is located in the zone covered by the microphone (S7).

【００２９】χ_Mを選択した際にχ_Mが基準値Ｔｈ１、
例えばｎ／３（ｎは分割帯域数）より大であるか否かを
調べ（Ｓ８）、大であればステップＳ７に移るようにし
てもよい。またステップＳ５の後、χ１，χ２，…中に
基準値Ｔｈ２、例えば２ｎ／３以上のものを探し（Ｓ
９）、あればそのχ_Mと対応するチャネルＭのマイクロ
ホンの受けもちゾーンに音源があると判定する（Ｓ
７）。更に精度よくゾーンを決めるには、ステップＳ９
で基準値以上のものχ_Mがあれば、そのＭと対応するマ
イクロホンと隣接するマイクロホンのチャネルＭ１，Ｍ
２のχ_M1，χ_M2を比較し、その大きい方χ_M'（Ｍ′は１
又は２）のＭ′と対応するマイクロホンとＭと対応する
マイクロホンとから音源ゾーンを決定する。つまりχ_M1
が大であれば、Ｍのマイクロホンの受けもちゾーン中の
Ｍ１と対応するマイクロホン側に位置していると判定す
る（Ｓ１１）。When χ _M is selected, χ _M is the reference value Th1,
For example, it may be checked whether it is larger than n / 3 (n is the number of divided bands) (S8), and if it is larger, the process may proceed to step S7. In addition, after step S5, a reference value Th2, for example, 2n / 3 or more is searched for in χ1, χ2, ...
9) If so, it is determined that there is a sound source in the susceptibility zone of the microphone of channel M corresponding to that χ _M (S).
7). To determine the zone more accurately, step S9
If there is a χ _{M that} is equal to or larger than the reference value, then the microphone corresponding to that M and the channels M1 and M of the adjacent microphones
2 χ _M1 and χ _M2 are compared, and the larger one χ _{M '} (M' is 1
Alternatively, the sound source zone is determined from the microphone corresponding to M ′ in 2) and the microphone corresponding to M. So χ _M1
Is large, it is determined that the microphone is located on the microphone side corresponding to M1 in the receiving zone of the M microphone (S11).

【００３０】この発明の音源ゾーン検出方法、その装置
によれば各マイクロホン出力信号を小さい帯域に分割
し、そのレベルあるいは到達時間差を帯域ごとに比較し
て、ゾーンを判定し、ヒストグラムを作る必要がなく、
実時間で音源ゾーンを検出できる。According to the sound source zone detecting method and the apparatus thereof of the present invention, it is necessary to divide each microphone output signal into small bands and compare the level or arrival time difference for each band to judge the zone and create a histogram. Without
The sound source zone can be detected in real time.

[Brief description of drawings]

【図１】この発明による装置の機能構成例を示すブロッ
ク図。FIG. 1 is a block diagram showing a functional configuration example of an apparatus according to the present invention.

【図２】マイクロホン配置と検出可能音源ゾーン分割の
例を示す図。FIG. 2 is a diagram showing an example of microphone arrangement and detectable sound source zone division.

【図３】マイクロホン配置と検出可能音源ゾーン分割の
例を示す図。FIG. 3 is a diagram showing an example of microphone arrangement and detectable sound source zone division.

【図４】この発明による装置の他の機能構成例を示すブ
ロック図。FIG. 4 is a block diagram showing another functional configuration example of the device according to the present invention.

【図５】この発明による方法の処理手順の例を示す流れ
図。FIG. 5 is a flowchart showing an example of a processing procedure of a method according to the present invention.

───────────────────────────────────────────────────── フロントページの続き (56)参考文献特開平１−109996（ＪＰ，Ａ) 特開平５−87903（ＪＰ，Ａ) (58)調査した分野(Int.Cl.⁷，ＤＢ名) H04R 27/00 G01S 5/18 H04R 29/00 320 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-109996 (JP, A) JP-A-5-87903 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04R 27/00 G01S 5/18 H04R 29/00 320

Claims

(57) [Claims]

1. A sound source zone detection method for determining a zone in which a sound source is located by using a plurality of microphones provided apart from each other, wherein each output channel signal of each microphone is divided into a plurality of frequency bands. Band-splitting and band-specific parameter values for detecting the level of the acoustic signal reaching the microphones that is divided and that changes for each same band of the signal to each output channel due to the positions of the plurality of microphones. a detection step, between the channel for each same band, and determining the highest level is high channel by comparing the level <br/> Le described above detects the number of the most level is high bandwidth for each channel a process of obtaining, a decision process that the number of highest level is high bandwidth required to determine the zone having undergone the microphone maximum channel as a sound source zone Sound source zone detection method according to claim to Rukoto.

2. The method according to claim 1 , wherein in the determination step, a sound source zone covered by a microphone of a channel in which the number of bands having the highest level is maximum and the number of bands is equal to or more than a reference value. A method for detecting a sound source zone, characterized by:

3. A plurality of micros provided separately from each other.
Sound source that determines the zone in which the sound source is located using a phone
A zone detection method, in which each output channel signal of each microphone described above
It is divided into wave number bands and the signal of each signal is output to each output channel.
Due to the position of the above multiple microphones for each band
Level of the acoustic signal reaching the microphone
Band-division / band-specific parameter value detection process for detecting values
When, the source zone determination process, between the channel for each same band, and determining the highest level is high channel by comparing the levels above detection, the number of the most level is high bandwidth for each channel A sound characterized by having a determining step and a determining step of determining as a sound source zone a zone that is received by a microphone of a channel in which the number of bands having the highest level obtained is equal to or greater than a reference value.
Source zone detection method.

4. The method according to claim 3 , wherein the number of microphones is three or more, and a comparison process of comparing the number of maximum level bands of each channel other than the channels having the reference value or more, and a comparison result thereof. , The zone of the sound source is determined from the zone covered by the microphones of the channels having the largest number of bands and the zone of the microphones of the channels exceeding the reference value with a narrower accuracy than the zone covered by one microphone. Sound characterized by having a process of
Source zone detection method.

5. A method according to any one of claims 1 to 3, said band division, band-specific parameter value detection process is a spectrum conversion step of converting said each channel signal, the power spectrum, respectively, each of A sound source zone detection method comprising a band division process of dividing a power spectrum of a channel into a plurality of frequency bands to obtain a level for each band.

6. The method according to any one of claims 1 to 5, the band division, the degree divided band signals of each output channel signal, consisting of components of an acoustic signal from primarily one source A method for detecting a sound source zone, characterized by dividing it into small parts.

7. A plurality of micros provided separately from each other.
Sound source that determines the zone in which the sound source is located using a phone
A zone detection method, in which each channel signal of each microphone is divided into
The region signal is mainly the component of the acoustic signal from one sound source.
A band dividing step of dividing into a plurality of frequency bands small as Li Cheng, a band-by-band time difference detection step of detecting the arrival time difference in the same band between each channel signal thereof separated between the channels for each same band , and determining a channel fastest reached by comparing the arrival time difference and the detected, a process of obtaining the number of bands were the fastest reach for each channel, the number of the fastest arrival the band the determined maximum source zone detection method comprising Rukoto a zone having undergone channel microphone of having a a determining step of determining the sound source zone.

8. The method according to claim 7 , wherein in the determination step, the sound source zone covered by the microphone of the channel in which the number of the bands that reach the fastest is the maximum and the number of the bands is the reference value or more. A method for detecting a sound source zone, characterized by:

9. A plurality of micros provided separately from each other.
Sound source that determines the zone in which the sound source is located using a phone
A zone detection method, in which each channel signal of each microphone is divided into
The region signal is mainly the component of the acoustic signal from one sound source.
Bands divided into multiple frequency bands
In the splitting process and in the same band between these separated channel signals
Bandwidth-based time difference detection process for detecting the arrival time difference, and the detected arrival between the channels for each same band.
Compare time differences to determine the fastest arriving channel
Process and the number of fastest arriving bands for each channel.
Degree and the sound source zone detection method comprising Rukoto which have a a determination process of determining zones with microphone receives the obtained fastest reached band channel number is equal to or larger than the reference value as the sound source zone.

10. The method according to claim 9 , wherein the number of microphones is three or more, and a comparison process for comparing the number of fastest arriving bands of each channel other than the reference or more channels, and the comparison process. As a result, the accuracy of the zone of the sound source is narrower than the zone of one microphone by the zone of the microphone of the channel having the largest number of bands and the zone of the microphone of the channel exceeding the reference value. And a sound source zone detection method.

11. A sound source zone detection device for determining a zone in which a sound source is located, by using a plurality of microphones provided apart from each other, wherein each output channel signal of each microphone is mainly stored in one sound source. A microphone that is divided into multiple frequency bands to the extent that only acoustic signal components are included, and that changes for each of the same bands of each of these divided output channel signals due to the positions of the multiple microphones. determining a band division, band-specific parameter value detection means for detecting the level of the acoustic signal, between the channel for each same band, the highest level is high channel by comparing the level <br/> Le that the detected reaching To obtain the number of bands with the highest level for each channel, and the channel with the largest number of bands with the highest level obtained. Sound source zone detection apparatus according to claim Rukoto that having a determination means for determining a zone with microphone receives Le as a sound source zone.

12. A plurality of microphones provided separately from each other.
Sound that determines the zone in which the sound source is located
A source zone detection device, wherein each output channel signal of each microphone is mainly
To the extent that only the sound signal component of one sound source is included,
Into a number of frequency bands and each of these
For each same band of output channel signal,
A microphone that changes due to the position of the microphone
Band-division / band-by-band detection to detect the level value of the reaching acoustic signal
Parameter value detection means, means for comparing the detected levels between the channels for each same band to determine the channel with the highest level, and the channel with the highest level for each channel A sound source zone detection device comprising: a means for obtaining the number and a determining means for determining, as a sound source zone, a zone covered by a microphone of a channel in which the obtained number of bands having the highest level is a reference value or more.

13. The device according to claim 12 , wherein the number of the microphones is three or more, and comparing means for comparing the number of maximum level bands of each channel other than the channels having the reference value or more, and a comparison result thereof. The zone of the sound source is determined with a narrower accuracy than that of one microphone, from the zone covered by the microphone of the channel whose maximum level is large and the zone covered by the microphone of the channel exceeding the reference value. A sound source zone detection device comprising:

14. A plurality of microphones provided separately from each other.
Sound that determines the zone in which the sound source is located
A source zone detector, which divides each output channel signal of each microphone above
Band signals are mainly composed of acoustic signals from one sound source.
Small enough to minute consisting of a band dividing means for dividing into a plurality of frequency bands, channels for each band among the divided each channel
More becomes band-by-band time difference detecting means for detecting the arrival time difference of the signal, between the channel for each same band, means for determining a fastest arrival channels by comparing the arrival time difference and the detected, for each channel fastest means for obtaining the number of the reached band, characterized Rukoto to have a decision means that the number of the fastest arrival the band sought to determine the maximum zone sound source zone the microphone has received the channel Sound source zone detection device.

15. A plurality of microphones provided separately from each other.
Sound that determines the zone in which the sound source is located
A source zone detector, which divides each output channel signal of each microphone above
Band signals are mainly composed of acoustic signals from one sound source.
Divided into multiple frequency bands, small enough to
A channel for each band between the band dividing means and each of the above divided channels.
It is called a time difference detection means for each band that detects the arrival time difference of signals.
And the detected arrival between the above channels for each same band.
Compare time differences to determine the fastest arriving channel
Means and method for finding the fastest number of bands reached for each channel
Sound source zone detection apparatus comprising: the stage, a Rukoto that having a determination means for determining the zones with the microphone receives the obtained fastest reached band channel number is equal to or larger than the reference value as the sound source zone.

16. The apparatus according to claim 15 , wherein the number of the microphones is three or more, and a comparison means for comparing the number of fastest arriving bands of each channel other than the reference or more channels, and the comparison means. As a result, the zone covered by the microphone of the channel having the largest number of bands and the zone covered by the microphone of the channel exceeding the reference value are used to narrow the zone of the sound source with a narrower accuracy than that of one microphone. A sound source zone detection device comprising: a means for determining.

17. A computer is caused to execute each step of the sound source zone detection method according to claim 1. Description:
A computer-readable recording medium in which a program for recording is recorded .