JP2667404B2 - Sound source locator - Google Patents
Sound source locatorInfo
- Publication number
- JP2667404B2 JP2667404B2 JP62229465A JP22946587A JP2667404B2 JP 2667404 B2 JP2667404 B2 JP 2667404B2 JP 62229465 A JP62229465 A JP 62229465A JP 22946587 A JP22946587 A JP 22946587A JP 2667404 B2 JP2667404 B2 JP 2667404B2
- Authority
- JP
- Japan
- Prior art keywords
- sound
- microphones
- sound source
- output
- image pickup
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Testing Or Calibration Of Command Recording Devices (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
- Closed-Circuit Television Systems (AREA)
- Audible And Visible Signals (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
Description
【発明の詳細な説明】
〔発明の目的〕
（産業上の利用分野）
この発明は機械類が設置されている現場などにおいて
異音を発する機器の探査を行う音源探査装置に関する。
（従来の技術）
従来の音源探査方法の一例を第２図に示す。（特開昭
49−60966号公報参照）第２図は３個のマイクロホンA,
B,Oを空間内に（a,o）、（o,b）、（o,o）の位置に設置
している。今Ｍ（xm,ym）の位置の機器の異常が起こ
り、その音が各マイクロホンA,B,Oによって検知された
とする。
今マイクロホンＯとマイクロホンＡとに到達する異常
音の時間差をΔt1とし、音の伝播速度をＣとすると▲
▼は次の式であらわされる。
同様にマイクロホンＯとマイクロホンＢとに到達する
異常音の時間差をΔt2とすると▲▼−▲▼は
式（１）と式（２）を連立させて解けば異常音を発生し
て機器の位置（xm,ym）が求められる。これは図式的に
示すと第３図に示すようにＯとＡを焦点とする双曲線３
とＯとＢを焦点とする双曲線４の交点を求めることにな
る。
ここで時間差を求めるにはマイクロホンから得られた
音響信号間の相互相関関数を用いる。
例えばΔt1を求めるにはマイクＡとマイクＯの信号間
の相互相関関数を求める。相互相関関数は第４図に示す
ようになり、その値の最大となる点までの時間を調べれ
ばそれがＭからマイクＡとマイクＯに到達する音の時間
差Δt1となる。
しかしこの方法の問題点と、相互相関関数からの時間
差の読取りが困難な場合があることで、例えばもし音の
信号が正弦波なら相互相関関数も正弦波となり、最大値
が周期的に組り返すので時間差の読取りは不可能であ
る。
また他の探査方法の一例を第５図に示す。（特公昭52
−47341号公報参照）第５図は２個のマイクロホンA,Bを
用い、音の来る方向を求めるものである。今ＡとＢ間の
距離をＬ、▲▼と垂直な方向に立てた軸Ｚ、マイク
Ａへの音の入射方向をθ、Ａに入射する音の線にＢから
おろした垂線の、その音線との交点をＱ、AQ間の距離を
Ｍとする。
音源はマイクロホンA,Bから十分遠方にあり、音源か
らの音波は平面波となって各マイクに入射するものとす
ると、音源の音が単一周波数の音の場合、マイクロホン
A,Bで検出される音波信号は
ｘ（ｔ）＝Dcos（２πｔ−φ） ……（３）
ｙ（ｔ）＝Dcos 2πｔ ……（４）
とあらわされる。ここでＤは平面波の振幅、は周波
数、φは距離差Ｍによって生じた位相差である。
幾何学的関係より
Ｍ＝Lsinθ ……（５）
またマイクA,Bに到達する時間差Δｔは音速をＣとし
て
（５），（６）から
これより
これより音源から来る音の方向θが求められる。ここ
で式（３）の位相差φを求めるにはマイクロホンA,B間
のクロススペクトルから求める。この方法の問題点は、
第５図の破線で示したように▲▼に対して線対称と
なるような方向との区別ができないことである。また平
面波を仮定しているが、音源が近くある場合にはこれは
成り立たない。
（発明が解決しようとする問題点）
即ち、これらの方法では、音源の音の性質や音源の位
置によっては精度が不十分になることが多く、信頼性の
高い音源探査装置をつくることができなかった。
〔発明の構成〕
（問題点を解決するための手段）
本発明の音源探査装置は、４個以上のマイクロホンを
用いて音を検出する音響検出手段と、前記マイクロホン
の出力をそれぞれディジタル化するA/D変換手段と、こ
のA/D変換手段により得られたそれぞれの信号をフーリ
エ変換するフーリエ変換手段と、このフーリエ変換手段
の出力からクロススペクトルをそれぞれ演算するクロス
スペクトル演算手段と、前記クロススペクトルから前記
４個以上のマイクロホンで得られる３次元的な各方向の
音響インテンシティを求め、これら音響インテンシティ
の成分をベクトル的に合成し、音の伝播して来る方向を
算出する方向検知手段と、映像を撮影するための撮像手
段と、前記方向検知手段の出力に基づいて前記撮像手段
が前記音の伝播して来る方向を向くように駆動する駆動
手段と、前記撮像手段により撮影された映像を表示する
ための表示手段とを備えたことを特徴としている。
（作用）
音響インテンシティとは音場のある点における音圧ｐ
（ｔ）と粒子速度ｕ（ｔ）の積の時間平均値で
で定義されるベクトル量であり、そのベクトルの向きは
伝播する音の方向をあらわす。
音響インテンシティを求めるには通常２個のマイクロ
ホンを用い、それらのクロススペクトルを計算して求め
る。即ち１〜２の周波数帯の音響インテンシティIr
（１〜２）は
から求められる。ここでρは空気密度、Δγは２個のマ
イク間の距離、G12（）はクロススペクトル、Imはそ
の虚数部をとることを意味する。ただしこの値は音響イ
ンテンシティの２個のマイクが並び方向の成分であり、
一次元的な量である。
３次元的な量を求めるには２個のマイクロホンで得ら
れる各方向の成分をベクトル的に合成すればよい。各マ
イクロホンで同時刻に測定するとすると３次元的な量を
計算するにはマイクロホンは最低４個必要である。ま
た、音源が必ずしも探査対象でなく、例えば人の話し声
のような外乱の場合もありうる。このような場合には音
の来る方向にテレビカメラを向けることで視覚的に確認
を行なうこともできる。
（実 施 例）
第１図は本発明の実施例を示す。
４本以上（第１図では３本に省略して図示している）
のマイクロホンで構成される音響検出部で検出された音
の信号はA/D変換部でディジタル信号に変換され、次に
フーリエ変換部で高速フーリエ変換（FFT）アルゴリズ
ムにより周波数スペクトルに分解される。
そしてフーリエ変換された出力からクロススペクトル
演算部でクロススペクトルを計算し、その出力を方向検
知部に送る。方向検知部ではクロススペクトルをもとに
音響インテンシティをそれぞれ求め、これらの音響イン
テンシティの各方向の成分をベクトル的に３次元に合成
し、音の来る方向を求める。
その結果は表示部に送られて表示されるとともにテレ
ビカメラを搭載した駆動部にも送られ、音の来る方向に
テレビカメラを動かす。テレビカメラで撮影している映
像は表示部に送られ、視覚的にも確認される。
〔発明の効果〕
このような構成にすれば工場設備等において異音を発
する機器の探査を迅速に行なうことができ、機器の保守
を容易にすることができる。DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a sound source detection device for searching for a device that emits abnormal noise at a site where machines are installed. (Prior Art) FIG. 2 shows an example of a conventional sound source searching method. (JP
FIG. 2 shows three microphones A,
B and O are installed in the space at (a, o), (o, b), and (o, o) positions. It is assumed that an abnormality has occurred in the device at the position of M (x m , y m ), and the sound has been detected by the microphones A, B, and O. Assuming that the time difference between the abnormal sounds reaching the microphones O and A is Δt 1 and the sound propagation speed is C,
▼ is represented by the following equation. Similarly, assuming that the time difference between the abnormal sounds reaching the microphones O and B is Δt 2 , ▲ ▼-▲ ▼ is If equations (1) and (2) are solved simultaneously, an abnormal sound is generated, and the position (x m , y m ) of the device is obtained. This is a hyperbola 3 whose focus is O and A as shown in FIG.
And the intersection of hyperbolas 4 with O and B as the focal points. Here, the cross-correlation function between the acoustic signals obtained from the microphones is used to obtain the time difference. For example, in order to obtain Δt 1 , the cross-correlation function between the signals of the microphone A and the microphone O is obtained. The cross-correlation function is as shown in FIG. 4. If the time to the point where the value of the cross-correlation function becomes maximum is checked, it becomes the time difference Δt 1 between the sound reaching the microphone A and the microphone O from M. However, the problem of this method and the difficulty in reading the time difference from the cross-correlation function may be that if the sound signal is a sine wave, the cross-correlation function will also be a sine wave, and the maximum value is periodically set. Since it returns, it is impossible to read the time difference. FIG. 5 shows an example of another search method. (Special Publication 52
FIG. 5 is for obtaining the direction in which the sound comes, using two microphones A and B. Now, the distance between A and B is L, the axis Z stands in the direction perpendicular to ▲ ▼, the incident direction of the sound to the microphone A is θ, and the sound of the perpendicular to the line of sound incident on A from B Let Q be the intersection with the line and M be the distance between AQ. If the sound source is located far enough from microphones A and B, and the sound wave from the sound source becomes a plane wave and enters each microphone, if the sound of the sound source is a sound of a single frequency, the microphone
The sound signals detected at A and B are expressed as x (t) = Dcos (2πt−φ) (3) y (t) = Dcos 2πt (4) Here, D is the amplitude of the plane wave, is the frequency, and φ is the phase difference caused by the distance difference M. From the geometrical relationship, M = Lsinθ (5) The time difference Δt to reach the microphones A and B is represented by From (5) and (6) Than this From this, the direction θ of the sound coming from the sound source is obtained. Here, the phase difference φ in equation (3) is found from the cross spectrum between the microphones A and B. The problem with this method is that
As shown by the broken line in FIG. 5, it cannot be distinguished from a direction that is line-symmetric with respect to the triangle. Although a plane wave is assumed, this does not hold when the sound source is near. (Problems to be Solved by the Invention) That is, in these methods, the accuracy often becomes insufficient depending on the nature of the sound of the sound source and the position of the sound source, and a highly reliable sound source search device can be manufactured. Did not. [Structure of the Invention] (Means for Solving the Problems) A sound source detection device of the present invention includes a sound detecting means for detecting sound using four or more microphones, and an A for digitizing the output of each of the microphones. / D conversion means, Fourier transform means for Fourier transforming each signal obtained by the A / D conversion means, cross spectrum calculation means for calculating a cross spectrum from the output of the Fourier transform means, and the cross spectrum A direction detecting means for obtaining a sound intensity in each of three-dimensional directions obtained by the four or more microphones from above, synthesizing these sound intensity components in a vector, and calculating a direction in which sound propagates; An image pickup means for photographing an image, and a direction in which the sound is propagated by the image pickup means based on an output of the direction detection means Driving means for driving to face, it is characterized by comprising display means for displaying the image captured by the imaging means. (Operation) The sound intensity is the sound pressure p at a certain point in the sound field.
The time average of the product of (t) and the particle velocity u (t) Is the vector quantity defined by, and the direction of the vector represents the direction of the propagating sound. To obtain the sound intensity, two microphones are usually used and their cross spectra are calculated. That is one to two of the acoustic intensity Ir of the frequency band
(1 to 2) Required from. Here ρ is air density, [Delta] [gamma] is the distance between the two microphones, G 12 () cross spectrum, is I m means taking the imaginary part. However, this value is a component in the direction in which the two microphones of the sound intensity are arranged.
It is a one-dimensional quantity. In order to obtain a three-dimensional quantity, the components in each direction obtained by the two microphones may be combined in vector. When measuring at the same time with each microphone, at least four microphones are required to calculate a three-dimensional quantity. Further, the sound source is not necessarily the object of exploration, and may be a disturbance such as a human voice. In such a case, the confirmation can be made visually by pointing the television camera in the direction from which the sound comes. (Embodiment) FIG. 1 shows an embodiment of the present invention. Four or more (illustrated in FIG. 1 by omitting three)
The sound signal detected by the sound detection unit composed of the microphones is converted into a digital signal by an A / D conversion unit, and then decomposed into a frequency spectrum by a fast Fourier transform (FFT) algorithm by a Fourier transform unit. Then, the cross spectrum calculation unit calculates a cross spectrum from the Fourier-transformed output and sends the output to the direction detection unit. The direction detection unit obtains the sound intensity based on the cross spectrum, synthesizes the components of the sound intensity in each direction into a three-dimensional vector, and obtains the direction from which the sound comes. The result is sent to the display unit for display, and is also sent to the drive unit equipped with the television camera, and moves the television camera in the direction from which sound comes. The video taken by the television camera is sent to the display unit and visually checked. [Effect of the Invention] With such a configuration, it is possible to quickly search for equipment that emits abnormal noise in factory equipment or the like, and to facilitate maintenance of the equipment.
【図面の簡単な説明】
第１図はこの発明の模式的ブロック図、第２図は従来の
音源探査方法の１例を示すマイクロホンの配置図、第３
図は第２図の探査の原理を示す説明図、第４図は相互相
関関数の例を示す波形図、第５図は従来の別の音源探査
方法の例を示す説明図である。
１……マイクロホン、２……テレビカメラ
３……ＯとＡを焦点とする双曲線
４……ＯとＢを焦点とする双曲線BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic block diagram of the present invention, FIG. 2 is a microphone arrangement diagram showing an example of a conventional sound source detection method, FIG.
FIG. 4 is an explanatory diagram showing the principle of the search shown in FIG. 2, FIG. 4 is a waveform diagram showing an example of a cross-correlation function, and FIG. 5 is an explanatory diagram showing another example of a conventional sound source searching method. 1 ... Microphone, 2 ... TV camera 3 ... Hyperbola with focus on O and A 4 ... Hyperbola with focus on O and B
Claims (1)
検出手段と、 前記マイクロホンの出力をそれぞれディジタル化するA/
D変換手段と、 このA/D変換手段により得られたそれぞれの信号をフー
リエ変換するフーリエ変換手段と、 このフーリエ変換手段の出力からクロススペクトルをそ
れぞれ演算するクロススペクトル演算手段と、 前記クロススペクトルから前記４個以上のマイクロホン
で得られる３次元的な各方向の音響インテンシティを求
め、これら音響インテンシティの成分をベクトル的に合
成し、音の伝播して来る方向を算出する方向検知手段
と、 映像を撮影するための撮影手段と、 前記方向検知手段の出力に基づいて前記撮像手段が前記
音の伝播して来る方向を向くように駆動する駆動手段
と、 前記撮像手段により撮影された映像を表示するための表
示手段と を備えたことを特徴とする音源探査装置。 ２．前記撮像手段としてテレビカメラを用いたことを特
徴とする特許請求の範囲第１項記載の音源探査装置。 ３．前記方向検知手段により求められた音の伝播して来
る方向を前記表示手段に表示させるための手段を備えて
いることを特徴とする特許請求の範囲第１項記載の音源
探査装置。(57) [Claims] 1. Sound detection means for detecting sound using four or more microphones, and A / D for digitizing the output of each of the microphones
D conversion means, Fourier transformation means for performing Fourier transformation on each signal obtained by the A / D conversion means, Cross spectrum calculation means for computing a cross spectrum from the output of the Fourier transformation means, and Direction detection means for obtaining three-dimensional sound intensity in each direction obtained by the four or more microphones, vector-wise combining these sound intensity components, and calculating a direction in which sound propagates; Photographing means for photographing an image; driving means for driving the image pickup means in a direction in which the sound propagates based on an output of the direction detection means; and driving the image photographed by the image pickup means. A sound source locating device comprising: display means for displaying. 2. The sound source search device according to claim 1, wherein a television camera is used as the image pickup means. 3. 2. The sound source searching apparatus according to claim 1, further comprising: means for displaying on the display means the direction in which the sound transmitted by the direction detecting means is transmitted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62229465A JP2667404B2 (en) | 1987-09-16 | 1987-09-16 | Sound source locator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62229465A JP2667404B2 (en) | 1987-09-16 | 1987-09-16 | Sound source locator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6473272A JPS6473272A (en) | 1989-03-17 |
| JP2667404B2 true JP2667404B2 (en) | 1997-10-27 |
Family
ID=16892623
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62229465A Expired - Lifetime JP2667404B2 (en) | 1987-09-16 | 1987-09-16 | Sound source locator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2667404B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017191362A1 (en) * | 2016-05-06 | 2017-11-09 | Procemex Oy | Acoustic analysation of an operational state of process machinery |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH10243494A (en) * | 1997-03-03 | 1998-09-11 | Nippon Telegr & Teleph Corp <Ntt> | Method and device for recognizing direction of face |
| JP4193041B2 (en) * | 2002-01-31 | 2008-12-10 | 学校法人 芝浦工業大学 | Three-dimensional intensity probe, three-dimensional sound source direction detection device and three-dimensional sound source direction facing control device using the probe |
| DE102005057569A1 (en) * | 2005-12-02 | 2007-06-06 | Robert Bosch Gmbh | Device for monitoring with at least one video camera |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58163883A (en) * | 1982-03-19 | 1983-09-28 | Toshiba Corp | Monitoring apparatus |
| JPS5961721A (en) * | 1982-10-01 | 1984-04-09 | Bridgestone Corp | Method and apparatus for searching sound source |
| JPS6123781U (en) * | 1984-07-13 | 1986-02-12 | 三菱電機株式会社 | On-site monitoring device |
-
1987
- 1987-09-16 JP JP62229465A patent/JP2667404B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017191362A1 (en) * | 2016-05-06 | 2017-11-09 | Procemex Oy | Acoustic analysation of an operational state of process machinery |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6473272A (en) | 1989-03-17 |
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