JP2000346757A - Method for analyzing sound source contribution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To analyze the contribution of a target noise source by shading as far as possible unneeded sounds other than a sound source, and obtaining a signal from the target noise source in the case of obtaining the contribution of each sound source at an evaluation point. SOLUTION: For eliminating a sound (sound from a background noise source) other than a target sound source, a microphone is installed near the background source, thus sensing the information of the background sound source. When a signal obtained by a microphone at an evaluation point is set to be m(t), y1(t) is set to be a sound from a target sound source, and y2(t) is set to be a sound from a background sound source, m(t) is defined by an expression m(t)=y1(t)+y2(t). For eliminating y2(t) from an acoustic signal by an evaluation microphone and an acoustic signal sensed by a microphone installed at the background sound source, an impulse response h(t) between the background sound source and the evaluation point is obtained. The h(t) is obtained from the signals of y2(t) and m(t) by a contribution analysis method. When the h(t) is obtained, y2(t) can be obtained from an expression y2(t)=∫h(t-r)m(r)dτ. By subtracting y2(t) from m(t), a desired signal can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for diagnosing the contribution of a sound source or a vibration source, and has one or a plurality of sound sources or vibration sources, which cause sound or vibration at an evaluation point. Such transmission systems, for example, parts that have a large contribution in terms of sound and vibration in fields such as general machinery, automobiles, building structures, OA equipment, railways,
Alternatively, it can be used for discriminating a transmission path and performing efficient improvement.

[0002]

2. Description of the Related Art In order to know the degree of influence of a sound source or a vibration source in a sound / vibration system, a method called masking is generally used. In this method, the influence of a certain sound source or vibration source is shielded by a lead plate or a sound insulating material, or removed by a vibration damping material or the like, and the degree of each effect is determined by comparison with a normal state. In addition to this, a true transfer function obtained by removing a correlation component from a transfer function between each sound source or vibration source and the evaluation point is obtained, and thereby, the degree of influence of each sound source or vibration source on the evaluation point,
That is, a contribution analysis method in the frequency domain that determines the degree of contribution has been devised.

[0003]

According to the above masking method, in a system in which sound and vibration affect each other like a general mechanical device, the influence on other parts is eliminated, and the sound or vibration of a certain part is eliminated. Since it is impossible to completely shut off, it is impossible to completely know only the influence of the site. That is, there is a problem that it is impossible to grasp the contribution in the actual operation state.

A method for solving this problem is disclosed in Japanese Patent Application Laid-Open No. 5-26722.
No., published in Japanese Unexamined Patent Publication No. This method eliminates the disadvantages of the microphone king method, but it is difficult to determine the contribution of the desired sound source if a loud sound mixes with the sound from the target sound source at the evaluation point. There is.

[0005] It is an object of the present invention to provide a method and apparatus that obviate the above-mentioned limitations.

[0006]

[Means for Solving the Problems] When analyzing the degree of contribution of one or more sound sources or vibration sources to the sound at the evaluation point, a sound collector is attached to the microphone at the evaluation point to collect the sound. Then, for each of the collected sounds, each detection signal of the sound or vibration detected in the vicinity of each sound source or vibration source is input to an adaptive filter, and the sum of the output signals of each adaptive filter is obtained. The coefficients of the adaptive filters are automatically updated so that the difference between the target signal of the sound or vibration detected at the point and the sum of the output signals is minimized, and each adaptive filter at the time when it converges to a certain value is used. A sound source / vibration source contribution analysis method is characterized in that the degree of contribution of each sound source or vibration source is analyzed based on an output signal of a filter.

When analyzing the degree to which one or a plurality of sound sources or vibration sources contribute to the sound at the evaluation point, a sound from a specific sound source other than the sound from the target sound source to the microphone at the evaluation point is analyzed. If sound is mixed in, place a microphone near this particular sound source,
Using the information obtained from the installed microphone, the microphone acoustic signal at the evaluation point is predicted, the predicted audio signal is subtracted from the acoustic signal obtained at the evaluation point, and the subtracted audio signal is calculated at the new evaluation point. As an acoustic signal, each sound signal or vibration detection signal detected in the vicinity of each sound source or vibration source with respect to this acoustic signal is input to an adaptive filter, and the sum of output signals of each adaptive filter is obtained. The coefficients of the respective adaptive filters are automatically updated so that the difference between the target signal of the sound or vibration detected at the point and the sum of the output signals is minimized, and the respective adaptive filters at the time when they converge to a certain value are automatically updated. The sound source characterized by analyzing the degree of contribution of each sound source or vibration source by the output signal of
A vibration source contribution analyzer.

[0008]

1 and 2 show an embodiment of the present invention.
Shown in FIG. 1 shows an example of the configuration of the present invention.

Consider a case where the ratio (contribution) of a noise source such as a plant is measured at a specific position outdoors. In this case, a problem is that noise other than the target noise source is often mixed outdoors, and it is difficult to obtain target noise information.

[0010] An object of the present invention is to obtain a signal from a target noise source by intercepting a sound other than an unnecessary source as much as possible when obtaining a contribution of each sound source at an evaluation point, and obtaining a signal from a target noise source. The purpose is to analyze the contribution of noise sources.

A sound collection device is attached to the evaluation microphone (hereinafter, microphone) shown in FIG. The contribution of each sound source at the evaluation point is obtained based on information obtained by the evaluation microphone to which the sound collecting device is attached, the microphone set near each sound source, or a vibration sensor.

The following advantages are obtained by attaching the sound collecting device to the evaluation microphone.

(1) With the sound collector, it is possible to efficiently capture only sound information in a specific sound source direction as a target.

(2) Non-target sound can be eliminated or reduced by the sound collector.

As described above, sound information in a target sound source direction can be efficiently captured. By performing a contribution analysis using the information obtained in this manner, a desired contribution of each sound source can be obtained.

If the location of the sound other than the target sound source is known to some extent, the following processing can be performed to remove this noise.

In the present invention, in order to accurately determine the contribution from a specific sound source, sounds other than the target sound source (hereinafter, sounds from a background noise source) are removed. For this reason,
As shown in FIG. 2, a microphone is installed near the background noise source, and information on the background noise source is sensed by the microphone.

The signal obtained by the microphone at the evaluation point is represented by m (t),
Assuming that y1 (t) is a sound from a target sound source and y2 (t) is a sound from a sound noise source, m (t) can be defined as follows.

[0019]

M (t) = y1 (t) + y2 (t) (1) In order to delete y2 (t) from the acoustic signal from the evaluation microphone and the acoustic signal sensed by the microphone installed in the background noise source, An impulse response h (t) between the background noise source and the evaluation point is obtained. h (t) can be determined from the signals of y2 (t) and m (t) by using a contribution analysis technique disclosed in, for example, Japanese Patent Application Laid-Open No. 5-26722.

If h (t) is obtained, y2 (t) can be obtained from equation (2).

[0021]

Y2 (t) = ∫h (t−τ) m (τ) dτ (2) By subtracting y2 (t) from m (t), a desired signal can be obtained. What is necessary is just to perform a contribution analysis on the signal obtained by this subtraction.

FIG. 3 shows the above algorithm, and FIG. 4 shows the configuration of this apparatus.

In the example described above, one background noise source is targeted. However, when there are a plurality of background noises, a plurality of microphones may be installed and the same processing may be performed.

[0024]

According to the present invention, the contribution of each target sound source can be obtained by removing the influence from sources other than the target sound source.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a sound collection device which is an example of the configuration of the present invention.

FIG. 2 is a configuration diagram showing an example of sensor arrangement for contribution analysis.

FIG. 3 is a flowchart showing a procedure of the present invention.

FIG. 4 is a configuration diagram of a sound collection device which is an example of the configuration of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... parabola, 2 ... evaluation point microphone, 3 ... reference signal microphone, 4 ... noise detection microphone, 5 ... contribution analysis device, 1
00a to 100d: low-pass filter, 110a to 110d
... A / D converters, 120a to 120d ... Band pass filters, 130a to 130c ... Adaptive filters, 1
40: Contribution analysis, 150: Display means.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Hiroyuki Mae 3-2-1, Sachimachi, Hitachi, Ibaraki Prefecture Inside Hitachi Engineering Co., Ltd. (72) Yoko Aikawa 3-2-2, Sachimachi, Hitachi, Ibaraki No. 1 Hitachi Engineering Co., Ltd. (72) Inventor Yasushi Takano 502 Kandachi-cho, Tsuchiura-shi, Ibaraki Pref. CC24 CC30

Claims (1)

[Claims] When analyzing the degree of contribution of one or more sound sources or vibration sources to sound at an evaluation point, a sound collector is attached to a microphone at the evaluation point to collect sound, and the sound is collected. For each of the sounds, each detection signal of the sound or vibration detected in the vicinity of each sound source or vibration source is input to an adaptive filter, the sum of the output signals of each adaptive filter is obtained, and the sum is detected at the evaluation point. The coefficient of each of the adaptive filters is automatically updated so that the difference between the target signal of sound or vibration and the sum of the output signals is minimized, and the output signal of each adaptive filter at the time of convergence to a certain constant value A method for analyzing the contribution of a sound source / vibration source, wherein the degree of contribution of each sound source or vibration source is analyzed by the method.