JP2010203800A - Method and apparatus for estimating sound source - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus therefor by which the sound source is estimated with high reliability even when sudden sound or intermittent sound occurs. <P>SOLUTION: Sound and image are sampled simultaneously using a sound/video sampling unit incorporating a plurality of microphones and a camera, and sound pressure waveform data and image data are then temporally stored in a buffer. When a command for a measurement start signal is issued from an image control unit at time t<SB>0</SB>, the data stored in the buffer during a period between time t<SB>1</SB>=t<SB>0</SB>-T<SB>z</SB>that is retroactive from time t<SB>0</SB>by a prescribed retroactive time length T<SB>z</SB>and time t<SB>2</SB>=t<SB>0</SB>+(T<SB>w</SB>-T<SB>z</SB>) is taken out, and a sound file and a video file are created to store them in a memory. A phase difference between sound pressure signals of the sound sampled by the plurality of microphones is calculated by using the sound pressure waveform data of the stored sound file so that the sound source direction is estimated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and apparatus for estimating a sound source using sound information collected by a plurality of microphones and video information photographed by a photographing means.

Conventionally, as a method of estimating the direction of sound arrival, a microphone array in which a large number of microphones are arranged at equal intervals is constructed, and the sound source direction that is the direction of sound wave arrival is estimated from the phase difference of each microphone relative to the reference microphone. So-called acoustic techniques have been devised (for example, see Non-Patent Document 1).
On the other hand, not a phase difference between output signals of a plurality of microphones arranged at a measurement point, but a plurality of microphone pairs arranged in a straight line intersecting each other from the plurality of microphones, and the position between the two microphones constituting the pair There has been proposed a method of estimating a sound source direction from a ratio between an arrival time difference corresponding to a phase difference and an arrival time difference between two paired two microphones (see, for example, Patent Documents 1 to 3).

  Specifically, as shown in FIG. 6, two microphone pairs (M1, M3) and microphone pairs (four microphones M1 to M4) are arranged at predetermined intervals on two straight lines orthogonal to each other. M2, M4) are arranged so as to constitute the microphone pair (M1, M3) and the microphones constituting the microphone pair (M2, M4) and the arrival time difference of the sound pressure signals input to the microphones M1, M3. The horizontal angle θ formed by the measurement point and the position of the sound source is estimated from the ratio between the arrival time differences of the sound pressure signals input to M2 and M4, and the fifth microphone M5 is placed on the plane formed by the microphones M1 to M4. Further, four microphone pairs (M5, M1), (M5, M2), (M5, M3), (M5, M4) are configured, The elevation angle φ formed by the measurement point and the position of the sound source is estimated from the arrival time difference between the microphones constituting the microphone pair.

Thereby, compared with the case where the sound source direction is estimated using the microphone array, the sound source direction can be accurately estimated with a small number of microphones.
Further, at this time, a video sampling means such as a CCD camera is provided to shoot a video of the estimated sound source direction, and then the video data and the data of the sound source direction are combined to generate the estimated sound source in the video. If the direction and the sound pressure level are displayed graphically, the sound source can be grasped visually.
At the same time as the sound is collected, the video is continuously captured by the video sampling means, and the video information is stored in the computer together with the sound information, and then the direction of the sound source is calculated and estimated in the video. There is also a method of estimating a sound source by displaying a figure of the sound source direction and sound pressure level.

Japanese Patent Laid-Open No. 2002-181913 JP 2006-324895 A JP 2008-224259 A

Toshiro Oga, Yoshio Yamazaki, Yutaka Kaneda; Acoustic system and digital processing, Corona, 1995

  By the way, in the above-described conventional method, sound information and video information collected for a predetermined measurement time (for example, 120 seconds) set in advance are captured in a computer, and then the sound source direction is determined using the captured information. I was doing calculations. Therefore, when sudden or intermittent sounds occur, measurement may be lost, and there is a problem that efficient measurement is difficult, such as analyzing only unnecessary data. .

  The present invention has been made in view of the conventional problems, and provides a method and apparatus capable of reliably estimating a sound source even when a sudden sound or an intermittent sound is generated. Objective.

  The invention according to claim 1 of the present application collects sound information and video information at the same time using a sound / video sampling unit in which a plurality of microphones and photographing means are integrated, and A sound source estimation method for estimating a sound source using sound pressure waveform data that is data of a sound pressure signal and image data of a collected video, the sound pressure waveform data of the collected sound and image data of the collected video Are stored in temporary storage files, and when a sound source direction measurement start command is issued, an analysis set in advance from a time that is a predetermined retrograde time length from the time when the measurement start command is issued. Sound pressure waveform data and image data stored in the temporary storage file are extracted up to the time elapsed by the length of time, and these data are extracted as sound file and video file respectively. As a storage means, using the sound pressure waveform data of the saved sound file, after calculating the phase difference between the sound pressure signals of the sound collected by the plurality of microphones to estimate the sound source direction, A figure indicating the estimated sound source direction is drawn by combining the estimated sound source direction and the image data captured within the time used for estimating the sound source direction stored in the moving image file. A sound source position estimation image is created, and a sound source is estimated using the sound source position estimation image.

  The invention according to claim 2 is the sound source estimation method according to claim 1, wherein sound information and video information are obtained using a sound / video sampling unit in which a plurality of microphones and photographing means are integrated. And a first step of A / D converting the collected sound pressure signal and video signal as sound pressure waveform data and image data, respectively, and storing the data for a predetermined period. A second step of saving in one storage means, a third step of issuing a sound source direction measurement start command, and sound pressure waveform data for an analysis time length used for estimation of the sound source from the first storage means; A fourth step of extracting image data and storing the extracted sound pressure waveform data and image data in a second storage means as a sound file and a moving image file, respectively, and a sound source direction from the sound file A fifth step of extracting sound pressure waveform data for a calculation time length used for estimation calculation, calculating a phase difference of sound pressure signals of sounds collected by the plurality of microphones, and estimating a sound source direction; and the moving image A sixth step of extracting image data at a time between the start time and end time of the calculation from the file, a sound source direction estimated in the fifth step, and a sound source direction extracted in the sixth step A seventh step of synthesizing with the image data to create and display a sound source position estimation image in which a graphic showing the estimated sound source direction is drawn; and an eighth step of estimating a sound source using the sound source position estimation image The sound pressure waveform data and the image data for the analysis time length extracted from the first storage means in the fourth step are the times when the measurement start command is issued. Than time Sound pressure waveform data and image data stored in the first storage means between a second time which is a time before the set retroactive time length and the first time, and the first The sound pressure waveform data stored in the first storage means from the first time to a third time that has passed by a time length shorter than the analysis time length by the backward time length. It is image data.

  A third aspect of the present invention is the sound source estimation method according to the second aspect, wherein a sound pressure waveform stored in the sound file is stored between the fourth step and the fifth step. A step of creating and displaying a graph of a time-series waveform of a sound pressure waveform from the data, and a step of designating an arbitrary time of the displayed graph are provided. In the fifth step, from the designated time Sound pressure waveform data for the operation time length is extracted from the sound file.

  According to a fourth aspect of the present invention, there is provided a microphone group having two pairs of microphones arranged at predetermined intervals on two mutually intersecting straight lines, a photographing means for photographing a sound source direction image, and a display means. An image in which a graphic showing the direction of the sound source is drawn from the sound pressure signal of the sound propagated from the sound source collected by the microphone group and the image signal of the direction of the sound source is generated and displayed on the display means. An apparatus for estimating a sound source to be estimated, wherein an A / D converter that converts a sound pressure signal collected by each microphone and a video signal photographed by a photographing means into digital signals, and the A / D converted sound A first storage means for temporarily storing a pressure signal as sound pressure waveform data, and temporarily storing the A / D converted video signal as image data for a predetermined period, and for starting estimation of a sound source direction Means for outputting a command signal; second storage means for storing sound pressure waveform data and image data used for sound source estimation; and when the command signal is input, the first storage means Extracting sound pressure waveform data and image data for an analysis time length used for estimation, creating a sound file and a moving image file, and outputting these files to the second storage means; Sound pressure waveform data corresponding to the calculation time length used for the calculation of the sound source direction is extracted from the sound file, and each of the microphones constituting the two microphone pairs is analyzed by frequency analysis of the extracted sound pressure waveform data. A sound source direction estimating means for estimating a sound source direction from the phase difference ratio of the two pairs of microphones thus determined, and starting the estimation calculation from the moving image file. Image data extraction means for extracting image data at a time between the time and the end time, and the estimated sound source direction data and the extracted image data are combined to indicate the estimated sound source direction Sound source position estimation image creation means for creating a sound source position estimation image on which a figure is drawn, and the analysis file creation means is set in advance from a first time which is a time when the measurement start command is issued. From the first time, the sound pressure waveform data and image data stored in the first storage means between the second time and the first time, which is the time before the backward time length, Sound pressure waveform data and image data stored in the first storage means from the first time to a third time that is shorter than the analysis time length by the backward time length. Extract the sound A file and the moving image file are created.

  According to a fifth aspect of the present invention, in the sound source estimating apparatus according to the fourth aspect, a fifth microphone not on a plane formed by the two pairs of microphones is added to the microphone group, and the sound source direction is added. In the estimation means, the four sets of microphones constituted by the phase difference between the microphones constituting the two sets of microphone pairs, and each of the fifth microphone and the four microphones constituting the two sets of microphone pairs. A sound source direction is estimated using a phase difference between microphones constituting a pair.

According to the present invention, sound information and video information are simultaneously collected using a sound / video sampling unit in which a plurality of microphones and photographing means are integrated, and the sound pressure signal data of the collected sound is collected. The sound pressure waveform data and the video image data are respectively stored in the primary storage file of the storage means, and when a command to start measurement of the sound source direction is issued, a predetermined backward time from the time when the command is issued Sound pressure waveform data and image data that are stored in the temporary storage file are extracted from a time that is back by a length of time to a time that has passed by a preset analysis time length, and these data are extracted as sound files and moving images. This is stored as a file in the storage means, and using the sound pressure waveform data of the stored sound file, the phase difference between the sound pressure signals of the sounds collected by the plurality of microphones is calculated. Since so as to estimate the sound source direction and, even if a sudden sound or intermittent sound is generated, the direction of the source of these sounds can be reliably estimated. Therefore, it is possible to eliminate measurement failures and prevent an increase in unnecessary measurement data, so that the sound source position can be estimated efficiently.
Further, when estimating the sound source, the estimated sound source direction and the image data captured within the estimation calculation time are combined, and a sound source position estimation image on which a figure indicating the estimated sound source direction is drawn is obtained. Since the sound source is created and estimated using the sound source position estimation image, the sound source can be reliably estimated.

In addition, if the sound source is estimated according to the steps described in claim 2, it is possible to reliably estimate the source of sudden or intermittent sound.
If the time series waveform of the sound pressure level to be displayed is the time series waveform of the magnitude of the collected sound, the sound source position can be estimated according to the magnitude of the propagation sound.
In addition, a time-series waveform graph of the sound pressure waveform is created and displayed from the sound pressure waveform data saved in the sound file, and an arbitrary time on this graph is specified, and the calculation time length from the specified time By extracting the sound pressure waveform data for the minute from the sound file and estimating the sound source direction, the sound pressure waveform data stored in the sound file can be used efficiently and effectively, so the sound source position is estimated. Can be performed efficiently.

In addition, by using the sound source estimation apparatus according to claim 4, it is possible to reliably estimate the source of sudden sound or intermittent sound.
At this time, the first to fourth microphones constituting the two microphone pairs arranged on the two straight lines intersecting each other at a predetermined interval and the fifth microphone not on the plane formed by the two microphone pairs And the sound source direction is estimated using the phase difference ratio between the microphones constituting the two microphone pairs and the phase difference between the first to fifth microphones. Then, the horizontal angle θ and the elevation angle φ can be estimated efficiently and accurately with a small number of microphones.

  The summary of the invention does not enumerate all necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

It is a functional block diagram which shows the structure of the sound source estimation system which concerns on this Embodiment. 3 is a flowchart illustrating a sound source estimation method according to the present invention. It is a figure for demonstrating the extraction method of the data in retrograde mode. It is a figure which shows an example of the display screen as which the sound source position estimation screen was displayed. It is a figure which shows an example of the display screen on which the graph of the time-sequential waveform of a sound pressure level was displayed. It is a figure which shows the arrangement | sequence of each microphone in the sound source search method using the conventional microphone pair.

  Hereinafter, the present invention will be described in detail through embodiments, but the following embodiments do not limit the invention according to the claims, and all combinations of features described in the embodiments are included. It is not necessarily essential for the solution of the invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a functional block diagram showing the configuration of the sound source estimation system.
The sound source estimation system includes a sound / video sampling unit 10, a control unit 20, and a sound source position estimation device 30.
The sound / image collection unit 10 includes a sound collection unit 11, a CCD camera (hereinafter referred to as a camera) 12 as a video collection unit, a microphone fixing unit 13, a camera support 14, a column 15, and a turntable 16. The base 17 is provided. The sound collection means 11 includes a plurality of microphones M1 to M5.
The microphones M1 to M5 are installed on the microphone fixing unit 13, the camera 12 is installed on the camera support base 14, and the microphone fixing unit 13 and the camera support base 14 are connected by three support columns 15. That is, the sound collection means 11 and the camera 12 are integrated. The microphones M1 to M5 are disposed on the upper part of the camera 12.
The base 17 is a support member composed of three legs, and the turntable 16 is installed on the base 17. The camera support 14 is mounted on the rotation member 16r of the turntable 16.
Therefore, the sound collecting means 11 and the camera 12 can be rotated together by rotating the rotating member 16r.
Microphones M1 to M5 each measure the sound pressure level of sound propagated from a sound source (not shown).

The arrangement of the microphones M1 to M5 is the same as that shown in FIG. 6, and two microphone pairs (M1) in which four microphones M1 to M4 are arranged at predetermined intervals on two straight lines orthogonal to each other. , M3) and the microphone pair (M2, M4), and the fifth microphone M5 is not located on the plane formed by the microphones M1 to M4, more specifically, the square formed by the microphones M1 to M4. It is arranged at the position of the apex of the quadrangular pyramid with the bottom face. Thereby, four pairs of microphones (M5, M1) to (M5, M4) are further configured.
In this example, the shooting direction of the camera 12 is set to a direction that passes through the intersection of the two orthogonal lines and forms approximately 45 ° with the two lines. Therefore, the direction of the sound / image collection unit 10 is the direction of the white arrow D in FIG. The camera 12 collects an image corresponding to the direction of the sound / image collection unit 10.

The control unit 20 includes a mode switching unit 21, an amplifier 22, an A / D converter 23, a video input / output unit 24, a buffer 25 serving as a first storage unit, an analysis time length setting unit 26, and a retroactive operation. Time length setting means 27 and file creation means 28 are provided.
The sound source position estimation apparatus 30 includes a memory 31 as a second storage means, a display means 32, a sound pressure waveform data extraction means 33, a sound source direction estimation means 34, an image data extraction means 35, and a data synthesis means 36. With.

The sound source estimation system of this example has two measurement modes, a normal mode and a backward mode.
In the normal mode, sound source estimation is performed using data for a predetermined analysis time length from the time when a measurement start signal, which is a command signal for starting estimation of the sound source direction, is input. In the retroactive mode, sound source estimation is performed using data at a time that is a predetermined time after the measurement start signal is input.
The mode switching means 21 includes a mode switching unit 21a, a measurement start signal output unit 21b, a measurable display unit 21p, a retroactive display 21q, and a measurement start switch 21S.
The mode switching unit 21a switches the measurement mode to one of the normal mode and the backward mode, and instructs the file creation unit 28 to extract data from the buffer 25.
The measurement start signal output unit 21b outputs a measurement start signal when the measurement start switch 21S is pressed.
The measurable display unit 21p makes the measurer visually recognize that the number of data that can be measured is stored in the buffer 25 by turning on the LED.
The retroactive effective display unit 21q causes the measurer to visually recognize that the number of backward data is stored in the buffer 25 by turning on the LED. In the retrograde mode, the measurement start signal is not output when the LED of the retroactive display 21q is not lit.

The amplifier 22 includes a low-pass filter, removes a high frequency noise component from the sound pressure signal of the sound collected by the microphones M <b> 1 to M <b> 5, amplifies the sound pressure signal, and outputs the amplified signal to the A / D converter 23. The A / D converter 23 creates sound pressure waveform data obtained by A / D converting the sound pressure signal, and outputs the sound pressure waveform data to the buffer 25.
The video input / output unit 24 inputs video signals continuously shot by the camera 12 and outputs image data in the shooting direction to the buffer 25 every predetermined time (for example, 1/30 second).
The buffer 25 temporarily stores the sound pressure waveform data and the image data for a predetermined period. The buffer 25 includes a first buffer 25a and a second buffer 25b.
When the first buffer 25a is full, new sound pressure waveform data and image data are stored in the second buffer 25b. When the second buffer 25b is full, all data stored in the first buffer 25a is deleted, and new sound pressure waveform data and image data are stored in the first buffer 25a.
When the sound pressure waveform data and the image data are stored in the first buffer 25a or the second buffer 25b, the sound pressure waveform data and the image data are stored in synchronization, or the sound pressure waveform data and the image data are stored. A known method can be used, such as storing image data with time data attached thereto.

The analysis time length setting means 26 sets an analysis time length T _w that is a time length for analyzing the sound pressure waveform data and the image data and estimating the sound source.
The retrograde time length setting means 27 sets the retrograde time length T _z from the first time t ₀ which is the time when the measurement start signal for estimating the sound source is issued.
The file creation means 28 reads from the buffer 25 between the second time t ₁ = t ₀ −T _z and the third time t ₂ = t ₀ + (T _w −T _z ). The sound pressure waveform data and image data stored in the buffer 25 are taken out, a sound file 31a is created from the sound pressure waveform data, a moving image file 31b is created from the image data, and these files 31a and 31b are stored in the memory 31. Save to.

The memory 31 stores the sound file 31a and the moving image file 31b created by the file creation means 28. The memory 31 is composed of RAM and can be rewritten.
The display means 32 includes an image display unit 32a that displays a sound source position estimation image that is an image for estimating a sound source position, which will be described later, and a sound pressure level display unit that indicates the relationship between the horizontal angle θ in the sound source direction and the sound pressure level. And a display screen 32M having 32b.
The sound pressure waveform data extracting means 33 extracts sound pressure waveform data for estimating the sound source direction, that is, sound pressure waveform data for a preset analysis time length from the sound file 31 a stored in the memory 31. The sound is output to the sound source direction estimating means 34.
The sound source direction estimating means 34 obtains the phase difference between the microphones M1 to M5 from the extracted sound pressure waveform data, estimates the sound source direction from the obtained phase difference, and outputs the estimation result to the data synthesizing means 36. To do. Details of the estimation of the sound source direction will be described later.

The image data extracting unit 35 extracts the image data at the middle time between the start time and the end time of the analysis time from the moving image file 31 b stored in the memory 31 and outputs the image data to the data combining unit 36.
The data synthesizing unit 36 synthesizes the sound source direction data estimated by the sound source direction estimating unit 34 and the image data output from the image data extracting unit 35, and the sound source direction in which a graphic showing the sound source direction is drawn in the image. An estimated image is created and output to the display means 32.

Next, a method for estimating the sound source direction using the sound source estimation system will be described with reference to the flowchart of FIG.
First, after the sound / video sampling unit 10, the control unit 20, and the sound source position estimating device 30 are connected, the sound / video sampling unit 10 is set at a measurement point (step S11).
Then, after setting a backward time length T _z and analysis time length T _w (step S12), and select the measurement mode (step S13).
First, the case where the measurement mode is set to the backward mode in step S13 will be described.
After selecting the measurement mode, the shooting direction of the camera 12 is directed to the planned measurement location, the sound is collected by the microphones M1 to M5, and the image of the planned measurement location is collected by the camera 12 (step S14).
In this example, the measurement planned location is a fountain where sound is generated intermittently, so measurement was performed with the sound / video sampling unit 10 fixed. When measuring near the fountain, the entire fountain does not enter the visual field of view, so the rotary table 16 is reciprocated around the center of the fountain at a slow speed of, for example, about 3 ° / sec. However, it is only necessary to collect sound and video. A rotation range of about ± 60 ° is appropriate.
Next, the output signals of the microphones M1 to M5 and the video signal of the camera 12 are A / D converted, respectively, and the sound pressure waveform data and image data (hereinafter referred to as data) are stored in the buffer 25 (step S15).

When data for the retrograde time length T _z is stored in the buffer 25, the LED of the retroactive display 21q is lit, so that the measurer determines whether measurement in the retrograde mode is possible by lighting this LED. (Step S16).
If the LED of the retroactive display 21q is not lit, data for the retrograde time length T _z is not stored in the buffer 25. Accordingly, since the measurement in the retrograde mode cannot be performed, the data storage is continued until the LED of the retroactive display 21q is turned on.
When the LED of the retroactive display 21q is lit, measurement in the retroactive mode is possible, so that a measurement start signal can be output at any time.

Next, it is determined whether or not a measurement start signal is output (step S17). If the measurement start signal is not output, data storage is continued.
Even after the measurement start signal is output, the operation of storing the output signals of the microphones M1 to M5 and the video signal of the camera 12 as sound pressure waveform data and image data in the buffer 25 is continued (step S18).
Then, whether the data of the analysis time length T _w in the buffer 25 are stored, checked by the lighting of the LED measurable display section 21p (step S19).
When the analysis time in the buffer 25 length T _w of data is not saved, it continues to store the data.
If the analysis time length T _w of data is stored in the buffer 25, since the LED measurable display unit 21p is turned, to create a sound file 31a and video file 31b extracts the data from the buffer 25, These files 31a and 31b are stored in the memory 31 (step S20).
In step S20, as shown in FIG. 3, the data retrieved from the buffer 25 is stored in the buffer 25 between the second time t ₁ = t ₀ -T _z and the first time t ₀ that is the measurement start time. in data stored and backward data D _z is stored data in the buffer 25 during a period from a first time t ₀ to a third time _{t 2 = t 0 + (T} w -T z) in It consists of some residual measurement data _Dr. That is, the waiting time from when the measurement start signal is output to when the data for the analysis time length T _w is stored in the buffer 25 is (T _w −T _z ).

Next, sound pressure waveform data having a preset calculation time length _Tc is extracted from the sound file, and the sound source direction is estimated (step S21).
The sound source direction is estimated by frequency-analyzing the sound pressure waveform data by FFT, obtaining the respective phase differences between the microphones M1 to M5 for each frequency, and estimating the sound source direction for each frequency from the obtained phase difference. To do. In this example, instead of the phase difference, the horizontal angle θ and the elevation angle φ are obtained using the arrival time difference which is a physical quantity proportional to the phase difference.
The calculation method of the horizontal angle θ and the elevation angle φ in step S21 will be described later.

Next, the image data located at the center time t _m of the calculation time, that is, at the time t _m = t _c + (T _c / 2), which is half the calculation time length T _c from the calculation start time t _{c. Gc} is extracted from the moving image file (step S22).
Then, the calculated sound source direction data (θ _f , φ _f ) for each frequency and the image data G _c are synthesized, and the synthesized sound source position estimation image is displayed on the display screen 32M of the display means 32. Is displayed as a sound source position estimation screen on the image display unit 32a provided in (Step S23).
Figure 4 is a diagram showing an example, in the image display unit 32a, on the image data G _c, source position estimation screen 38 is displayed graphic (circles tracery) 37 is drawn representing the sound source direction Is done. The horizontal axis of the sound source position estimation screen 38 is the horizontal angle θ _f , and the vertical axis is the elevation angle φ _f . The size of the circle represents the sound pressure level.
It is also possible to display the estimated sound source direction for each preset frequency band. In this case, the color of the mesh-shaped circle 37 may be set for each frequency band.
The sound pressure level display section 32b displays a sound pressure level display screen 39 that displays the sound pressure level (dB) when the horizontal axis is the horizontal angle θ (deg.).
Finally, a sound source is estimated from the sound source position estimation screen 38 (step S24). On the sound source position estimation screen 38, the image of the sound source is estimated as the image shown in the location where the graphic 37 representing the sound source direction is drawn.

If the normal mode is selected in step S13, the process proceeds to step S25, the shooting direction of the camera 12 is directed to the planned measurement location, sound is collected by the microphones M1 to M5, and the measured measurement location is captured by the camera 12. And the output signals of the microphones M1 to M5 and the video signal of the camera 12 are A / D converted, respectively, and the sound pressure waveform data and the image data are stored in the buffer 25.
Next, it is determined whether or not a measurement start signal is output (step S26). If the measurement start signal is not output, data storage is continued.
Even after the measurement start signal is output, the operation of storing the output signals of the microphones M1 to M5 and the video signal of the camera 12 as sound pressure waveform data and image data in the buffer 25 is continued (step S27).
Then, whether the data of the analysis time length T _w in the buffer 25 are stored, checked by the lighting of the LED measurable display section 21p (step S28).
When the analysis time in the buffer 25 length T _w of data is not saved, it continues to store the data.
If the analysis time length T _w of data is stored in the buffer 25, since the LED measurable display unit 21p is turned, to create a sound file 31a and video file 31b extracts the data from the buffer 25, These files 31a and 31b are stored in the memory 31 (step S29).
In step S29, the data retrieved from the buffer 25 is data stored in the buffer 25 from the measurement start time t ₀ to the time t _w = t ₀ + T _w when the analysis time length T _{w has} elapsed. .
Since the sound source direction estimation, image data extraction, sound source position estimation screen creation and display, and sound source estimation processing steps performed after step S29 are the same in the normal mode and the retroactive mode, the sound file 31a. And the moving image file 31b are stored in the memory 31, the process proceeds to step S21, and the processing from step S21 to step S24 is performed to estimate the sound source.

すなわち、互いに直交する２直線上にそれぞれ所定の間隔で配置された２組のマイクロフォン対（Ｍ１，Ｍ３）及びマイクロフォン対（Ｍ２，Ｍ４）を構成するマイクロフォンＭ１，Ｍ３に入力する音圧信号の到達時間差Ｄ₁₃と、前記マイクロフォン対（Ｍ２，Ｍ４）を構成するマイクロフォンＭ２，Ｍ４に入力する音圧信号の到達時間差Ｄ₂₄との比から、計測点と音源位置との水平角θを推定し、前記到達時間差Ｄ₁₃，Ｄ₂₄と、前記第５のマイクロフォンＭ５と他のマイクロフォンＭ１〜Ｍ４との到達時間差Ｄ_5j（ｊ＝１〜４）とから計測点と音源位置との成す仰角φを推定する。 The calculation method of the horizontal angle θ and the elevation angle φ in step S21 is as follows.
When the arrival time difference between the microphone Mi and the microphone Mj of each microphone pair (Mi, Mj) is D _ij , the horizontal angle θ and the elevation angle φ, which are the sound incident directions, are expressed by the following equations (1) and (2). Therefore, the horizontal angle θ is obtained by frequency-analyzing the output signals of the microphones M1 to M5 using FFT and calculating the arrival time difference D _ij between the microphones M _i and M _j at the target frequency f. And the elevation angle φ can be obtained.

That is, arrival of sound pressure signals input to the microphones M1 and M3 constituting the two microphone pairs (M1, M3) and the microphone pairs (M2, M4) arranged at predetermined intervals on two orthogonal lines. The horizontal angle θ between the measurement point and the sound source position is estimated from the ratio between the time difference D ₁₃ and the arrival time difference D ₂₄ of the sound pressure signals input to the microphones M2 and M4 constituting the microphone pair (M2, M4). The elevation angle φ between the measurement point and the sound source position is estimated from the arrival time differences D ₁₃ and D ₂₄ and the arrival time differences D _5j (j = 1 to 4) between the fifth microphone M5 and the other microphones M1 to M4. To do.

音源方向の推定結果は、所定時間毎に記憶された撮影方向の画像データ毎に行う。 The arrival time difference D _ij is obtained as a cross spectrum P _ij (f) of signals input to the two microphone pairs (M _i , M _j ), and further, the phase angle information ψ ( rad) is calculated by the following equation (3).

The estimation result of the sound source direction is performed for each image data in the shooting direction stored every predetermined time.

As described above, in the present embodiment, sound and video are simultaneously collected using the sound / video sampling unit 10 in which the plurality of microphones M1 to M5 and the camera 12 are integrated, and then A / D converted and buffered. 25, and when a measurement start signal command is issued from the control unit 20, a second time that is traced back by a predetermined retrograde time length T _z from the first time t ₀ when the command is issued. The sound pressure waveform data and the image data stored in the buffer 25 are extracted between t ₁ = t ₀ -T _z and the third time t ₂ = t ₀ + (T _w −T _z ). The sound file 31a is created from the sound pressure waveform data, the moving image file 31b is created from the image data, the files 31a and 31b are stored in the memory 31, and the sound pressure waveform data of the stored sound file 31a is stored. Using Since the phase difference between the sound pressure signals of the sounds collected by the microphones M1 to M5 is calculated to estimate the horizontal angle θ and the elevation angle φ as the sound source direction, sudden or intermittent sounds are generated. Even if it occurs, the direction of the source of these sounds can be reliably estimated. Accordingly, measurement failures can be eliminated.
Further, when estimating the sound source, the estimated sound source direction (θ, φ) and the image data G _c photographed within the calculation time length T _c are combined, and the figure 37 indicating the estimated sound source direction is combined. Since the sound source position estimation screen 38 on which is drawn is displayed and the sound source is estimated, the sound source can be reliably estimated.

In the above embodiment, the direction of the sound source is estimated from the beginning of the sound file. However, the sound pressure waveform data is called from the sound file, and a graph of the time series waveform of the sound pressure level is created. The time position of the sound pressure waveform data having the calculation time length _Tc to be extracted by using the sound file may be specified.
FIG. 5 is a diagram showing an example of a time-series waveform graph of the sound pressure level. When the time-series waveform graph of the sound pressure level is displayed on the display screen 32M, the sound displayed on the sound pressure level display screen 39 is displayed. A time-series waveform graph of the sound pressure level is displayed on the pressure level display unit 32b. The horizontal axis of the graph is time (seconds), and the vertical axis is the sound pressure level (dB). By specifying a specific point (here, a peak at 3 seconds after measurement) on the graph of the time-series waveform of the sound pressure level, it is possible to specify a time position for analyzing the sound source direction.
The graph of the time-series waveform of the sound pressure level may be a graph showing the volume of the collected sound, that is, the time change of the sound pressure level of all frequencies, or the time of the sound pressure level in a preset frequency band. It may be a graph showing changes.
In FIG. 5, the sound pressure level increases each time water spouts, so by specifying the peak on the graph and estimating the sound source direction, the sound generated from which part of the fountain the specified peak Can be estimated.

  In the above example, the horizontal angle θ and the elevation angle φ formed by the measurement point and the sound source position are estimated using the five microphones M1 to M5. However, when the sound source position is sufficient only by the horizontal angle θ. The microphone M5 may be omitted, and only two pairs of microphones (M1, M3) and (M2, M4) arranged at predetermined intervals on two straight lines that intersect with each other may be used.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the embodiment. It is apparent from the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  As described above, according to the present invention, it is possible to reliably estimate a sound source even when a sudden sound or an intermittent sound is generated. Can be estimated efficiently.

10 sound / video sampling unit, 11 sound sampling means, M1-M5 microphone,
12 CCD camera, 13 microphone fixing part, 14 camera support base, 15 struts, 16 rotating base, 17 base, 20 control unit, 21 mode switching means,
21a mode switching unit, 21b measurement start signal output unit, 21p measurable display unit,
21q retroactive display unit, 22 amplifier, 23 A / D converter, 24 video input / output means, 25 buffer, 25a first buffer, 25b second buffer,
26 analysis time length setting means, 27 retrograde time length setting means, 28 file creation means,
30 sound source position estimation device, 31 memory, 31a sound file,
31b video file, 32 display means, 32M display screen, 32a image display section,
32b Sound pressure level display section, 33 Sound pressure waveform data extracting means,
34 sound source direction estimation means, 35 image data extraction means, 36 data synthesis means,
37 graphic representing sound source direction, 38 sound source position estimation screen, 39 sound pressure level display screen.

Claims (5)

  Sound pressure waveform data, which is the sound pressure signal data of the collected sound, is collected at the same time using a sound / video sampling unit in which a plurality of microphones and photographing means are integrated. And the image data of the collected video are respectively saved in a temporary storage file, and when a measurement start command in the direction of the sound source is issued, a predetermined retrograde time length is traced back from the time when the measurement start command is issued. The sound pressure waveform data and image data that are stored in the temporary storage file are extracted from the time up to the time that has passed for a predetermined analysis time length, and these data are stored as a sound file and a moving image file, respectively. The phase difference between the sound pressure signals of the sound collected by the plurality of microphones is saved using the sound pressure waveform data of the saved sound file. After estimating the sound source direction, the estimated sound source direction and the image data captured within the time used for estimating the sound source direction stored in the moving image file are combined to obtain the estimated A sound source estimation method comprising: generating a sound source position estimation image on which a graphic indicating a sound source direction is drawn, and estimating the sound source using the sound source position estimation image. A first step of simultaneously collecting sound information and video information using a sound / video sampling unit in which a plurality of microphones and photographing means are integrated;
A second step of A / D-converting the collected sound pressure signal and video signal and storing the sound pressure waveform data and image data in first storage means for storing the data for a predetermined period, respectively. When,
A third step of issuing a command to start measurement of the sound source direction;
Extracting sound pressure waveform data and image data for the analysis time length used for sound source estimation from the first storage means, and extracting the extracted sound pressure waveform data and image data as a sound file and a moving image file, respectively. A fourth step of storing in a second storage means;
The sound pressure waveform data for the calculation time length used for the sound source direction estimation calculation is extracted from the sound file, and the sound source direction is estimated by calculating the phase difference between the sound pressure signals collected by the plurality of microphones. A fifth step;
A sixth step of extracting image data at a time between a start time and an end time of the calculation from the moving image file;
The sound source direction estimated in the fifth step and the image data extracted in the sixth step are combined to create a sound source position estimation image in which a graphic showing the estimated sound source direction is drawn. A seventh step of displaying;
And an eighth step of estimating a sound source using the sound source position estimation image,
The sound pressure waveform data and the image data for the analysis time length extracted from the first storage means in the fourth step are set in advance from the first time which is the time when the measurement start command is issued. From the first time, the sound pressure waveform data and image data stored in the first storage means between the second time and the first time, which is the time before the backward time length, Sound pressure waveform data and image data stored in the first storage means from the first time to a third time that has passed by a time length shorter than the analysis time length by the backward time length. The sound source estimation method according to claim 1, wherein the sound source is estimated. Creating and displaying a time-series waveform graph of the sound pressure waveform from the sound pressure waveform data stored in the sound file between the fourth step and the fifth step;
Providing an arbitrary time of the displayed graph,
The sound source estimation method according to claim 2, wherein in the fifth step, sound pressure waveform data corresponding to the calculation time length is extracted from the sound file from a specified time. Providing a microphone group having two pairs of microphones arranged at predetermined intervals on two intersecting straight lines, a photographing means for photographing a sound source direction image and a display means, and propagating from the sound source collected by the microphone group A sound source estimation apparatus that creates an image in which a graphic showing a sound source direction is drawn from a sound pressure signal of a sound and a video signal obtained by capturing the sound source direction, displays the image on a display unit, and estimates a sound source;
An A / D converter that converts the sound pressure signal collected by each microphone and the video signal photographed by the photographing means into digital signals,
First storage means for temporarily storing the A / D converted sound pressure signal as sound pressure waveform data and temporarily storing the A / D converted video signal as image data;
Means for outputting a command signal for starting estimation of the sound source direction;
Second storage means for storing sound pressure waveform data and image data used for sound source estimation;
When the command signal is input, the sound pressure waveform data and the image data for the analysis time length used for estimation of the sound source are extracted from the first storage means, and a sound file and a video file are created, Analysis file creation means for outputting these files to the second storage means;
Sound pressure waveform data corresponding to the calculation time length used for the calculation of the sound source direction is extracted from the sound file, and frequency analysis is performed on the extracted sound pressure waveform data to each of the microphones constituting the two microphone pairs. Sound source direction estimating means for estimating the sound source direction from the ratio of the phase differences of the two obtained microphone pairs,
Image data extraction means for extracting image data at a time between the start time and end time of the estimation calculation from the video file;
Sound source position estimated image creating means for creating a sound source position estimated image in which a figure showing the estimated sound source direction is drawn by combining the estimated sound source direction data and the extracted image data; ,
The analysis file creation means includes a second time that is a time before the first time from a first time that is a time at which the measurement start command is issued, and a time that is a time before the first time. Between the sound pressure waveform data and the image data stored in the first storage means in the meantime, from the first time, the time length shorter than the analysis time length from the first time by the backward time length The sound file and the moving image file are created by extracting the sound pressure waveform data and the image data stored in the first storage means until the third time that elapses. Estimating device.   A fifth microphone that is not on the plane formed by the two sets of microphone pairs is added to the microphone group, and the sound source direction estimation means includes a phase difference between the microphones constituting the two sets of microphone pairs, and A sound source direction is estimated using a fifth microphone and a phase difference between the microphones constituting the four pairs of microphones constituted by each of the four microphones constituting the two pairs of microphones. The sound source estimation apparatus according to claim 4.

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