JPH0534609B2 - - Google Patents

Description

[Detailed Description of the Invention] 〓Field of Industrial Application〓 The present invention relates to a noise measuring device, and particularly to a device for acoustically imaging noise generated by various objects to be measured such as an engine using a parabolic sound collector. , relates to a device that captures sound imaged by a microphone array to form a sound image.

〓Summary of the Invention〓 The present invention comprises a three-axis acoustic intensity probe for each microphone element of an acoustic microphone array for recording sound acoustically imaged by a parabolic sound collector. It is designed to measure not only the iso-sound pressure level diagram but also the sound vector.

= Conventional technology = For example, Precision Machinery Vol. 51, No. 8 (1985), p-1521
As disclosed in , a device using a parabolic sound collector has been proposed to measure various types of mechanical noise. According to this device, when noise is acoustically imaged by a parabolic sound collector, the sound is captured by an acoustic array placed on the image plane, processed by a computer, and then processed by a CRT. The noise measurement results are displayed on the screen as an iso-sound pressure level diagram. According to such a device, it is possible to easily and accurately locate the sound source in a short time, and it becomes an effective means for analyzing noise from engines and the like.

〓Problems to be solved by the invention〓 However, according to conventional noise measurement devices using such parabolic sound collectors, the microphone array has a structure in which microphone elements are arranged in a matrix, so that the microphone elements are not directed toward the sound source. Even if there was a directivity, there was no way to measure this directivity, and this could lead to misidentification of the sound source.

The present invention has been made in view of these problems, and aims to measure the directivity of a sound source by measuring the sound vector, thereby preventing misidentification of the sound source. This is how it was done.

〓Means for solving the problem〓 The present invention acoustically images the noise generated by the object to be measured using a parabolic sound collector, and also uses an acoustic microphone array arranged on the imaging surface. A device that takes in imaged sound to form a sound image, and displays an object image obtained by a camera arranged in an imaging section of the parabolic sound collector and the sound image in a superimposed manner on a display, The microphone array is configured by arranging microphone elements in a matrix, each consisting of a 3-axis acoustic intensive probe with intensive probes arranged at the center and each vertex of a regular triangle, and the object to be measured is generated by the microphone array. The present invention relates to a noise measuring device characterized in that it measures a vector of noise.

〓Effect〓 The vector of the noise generated by the object to be measured is determined by the microphone element, which is composed of a 3-axis acoustic intensive probe arranged in a matrix, with intensive probes arranged at the center and each vertex of the triangle. This means that measurements can be performed at multiple points, and if the sound source has directivity, it becomes possible to observe this directivity.

Embodiment FIG. 3 shows a noise measuring device according to an embodiment of the present invention, and this device measures, for example, an engine 10 as an object to be measured.
And the parabolic sound collector 11 towards the engine 10
are being arranged. Parabolic sound collector 1
A microphone array 12 and a video camera 13 are arranged at the center of the camera. The microphone array 12 includes an amplifier 14, a bandpass filter 15,
Amplifier 16, effective value circuit 17, multiplexer 1
8, and the CPU 20 via the A/D converter 19.
It is becoming connected to. On the other hand, the video camera 13 is connected to the CPU via the image memory 21.
20. A CRT 22 and a printer 23 are connected to the output side of the CPU 20.

As shown in FIG. It consists of two acoustic intensity probes.
6 is placed at a position corresponding to the center of the equilateral triangle and each vertex, and thereby X, Y, Z
A three-axis acoustic intensity probe 26 is constructed. As shown in FIG. 2, 13 such microphone elements 25 are arranged in one row in the microphone array 12, and 14 rows of microphone elements 25 are provided.

In the above configuration, the parabolic sound collector 1
1 captures sound as a wave similar to light, and uses this sound collector 11 to image the intensity of the sound generated from the surface of the object to be measured 10, and each microphone of the microphone array 12 arranged on this imaging surface. The sound signal is taken into the element 25 and a sound image on the surface of the microphone array 12 is recorded. This sound image and the object image of the object to be measured 10 captured by the video camera 13 attached to the center of the parabolic sound collector 11 are superimposed and displayed on the CRT 22 as shown in FIG. 27, and the sound is visualized in real time.

The sound imaged by the parabolic sound collector 11 is imaged onto the microphone array 12, and this wave signal is taken into the microphone element 25, and the amplifier 14
The signal is amplified by a filter 15, passed through an amplifier 16, converted into an effective value by an effective value circuit 17, passed through a multiplexer 18, converted into a digital signal by an A/D converter 19, and then taken into the CPU 20. It's getting old.

The recorded sound signal can be transferred to CRT22 in various forms.
will be displayed on the display. In other words, the object to be measured 1
The iso-sound pressure level diagram 27 is displayed in a state overlapping with the image of 0. Further, the microphone element 25 is composed of four intensity probes 26, which measure the acoustic vector at each position. The results are analyzed by the CPU 20 and displayed on the CRT 22 as a vector diagram 28. In addition to the vector diagram 28, a projected diagram 29 of the object to be measured 10 is displayed on the CRT 22.

As described above, according to the noise measurement device according to the present embodiment, the three-axis acoustic intensity probes 26 are installed at multiple points at the position of the sound source image formed by the parabolic sound collector 11, and the three-axis acoustic intensity probes 26 are installed at multiple points. Based on the output of the intensity probe 26, the acoustic intensity level and vector at that point are analyzed by the CPU 20 and displayed on the CRT 22. The display on the CRT is made by using arrows to indicate the sound source and recorded sound vector 28 in an arbitrary cross section, along with the iso-sound pressure level diagram 27 for the projection diagram. Therefore, even if the sound source has directivity, there is no misidentification of the sound source, and it becomes possible to instantaneously measure the sound distribution and sound vector of the sound source.

<Effects of the Invention> As described above, the present invention configures a microphone array by arranging microphone elements in a matrix, each consisting of a 3-axis acoustic intensive probe in which intensive probes are arranged at the center and each vertex of a triangle. A microphone array is used to measure the vector of noise generated by an object to be measured.

Therefore, it is possible to detect not only the sound pressure distribution of the sound source but also the sound vector at multiple points using a microphone array in which microphone elements consisting of 3-axis acoustic intensity probes are arranged in a matrix. Even when the noise generated by the object to be measured has directionality, this directionality can be reliably measured, thereby eliminating the possibility of misidentifying the sound source.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a three-axis intensity probe of a noise measuring device according to an embodiment of the present invention, Fig. 2 is a front view of an acoustic microphone array, and Fig. 3 is a block diagram showing the overall configuration of the measuring device. , FIG. 4 is a front view of the CRT screen showing the measurement results. In addition, in the symbols used in the drawings, 10...engine (object to be measured), 11...parabolic sound collector, 12...
Microphone array, 13... Video camera, 20...
CPU, 22...CRT, 25...mic element,
26... 3-axis intensity probe, 27... Equal sound pressure level diagram, 28... Vector diagram.

Claims (1)

[Claims] 1. The noise generated by the object to be measured is acoustically imaged by a parabolic sound collector, and the imaged sound is captured by an acoustic microphone array arranged on the imaging plane. In the apparatus, the object image obtained by a camera disposed in the imaging section of the parabolic sound collector and the sound image are superimposed and displayed on a display, the center and each vertex of the regular triangle being The microphone array is constructed by arranging microphone elements each consisting of a three-axis acoustic intensive probe in a matrix, and the microphone array is configured to measure a vector of noise generated by the object to be measured using the microphone array. A noise measuring device characterized by: