It is possible to simultaneously identify the sound coming direction from a sound source in all directions and estimate the sound intensity of the sound source. A plurality of microphones (11) are arranged on the surface of a baffle (10) of a shape such as a sphere and polyhedron so that sound from all directions are acquired. A calculation device (40) calculates the amplitude characteristic and the phase characteristic of acoustic signals acquired by the microphones (11). The signal information and information on sound field analysis around the baffle are integrated and calculation to emphasize a sound coming from a particular direction is performed for all the directions so as to identify the sound coming direction from a sound source. According to these calculation results and the distance input by an input device (70), it is possible to estimate the sound intensity of the sound source at a plurality of portions generated at the sound source or boundary surface.

Sound source search system

PROBLEM TO BE SOLVED: To shorten a time for diagnosing abnormality of an inspection object, and to improve diagnostic performance in an acoustic diagnostic device. SOLUTION: This acoustic sensor array 32 is constituted by disposing in a grid-like shape acoustic sensors 10 having a function for decomposing into each frequency band. The acoustic sensor array 32 is arranged near the inspection object 31, and a sound emitted from the inspection object 31 is measured. The measured sound is decomposed into the frequency bands by each acoustic sensor, converted into signals, and outputted to an information processing part 34. In the information processing part 34, the signals from all the acoustic sensors are synthesized by a phased array method, and a map for showing the sound pressure intensity is created. Diagnosis of normality or abnormality of the inspection object 31 is performed based on the map. COPYRIGHT: (C)2004,JPO&NCIPI

Acoustic sensor array, acoustic diagnostic device and acoustic diagnostic method

PROBLEM TO BE SOLVED: To provide an axle bearing monitoring system for rolling stocks by axle box sound measurement capable of accurately detecting axile sounds of axle bearings of rolling stocks and its monitoring method. SOLUTION: The axle bearing monitoring system for rolling stocks by axle box sound measurement is provided with axle box sound detection devices 4 and 5 for arranging microphones 4A on both sides of rails, mounting the microphones 4A in such a way as to be more offset to the side of axile boxes than a focal position of a parabola reflector 4B is to capture only axile box sounds, and lengthening the time during which the axle boxes are present in a measurable section; a wheel detection means for acquiring information from wheel sensing devices 11-14; and an analysis device 20 for analyzing output information from the axle box sound detection devices 4 and 5 and the wheel sensing means. COPYRIGHT: (C)2006,JPO&NCIPI

Axle bearing monitoring system for rolling stock by axle box sound measurement and its monitoring method

PROBLEM TO BE SOLVED: To provide a sound collecting system which can be easily arranged and can acquire accurate data. SOLUTION: The sound collecting device 10 comprises a reflecting plate 14 having an inner curved surface as an ellipsoid of revolution and a plurality of microphones 12 arranged on a straight line running through a focal point of the inner curved surface to collect sonic waves from specific sound source collecting positions in a sound source survey region. The sonic waves from the sound source collecting positions each reflect from the inner curved surface of the reflecting plate, reach the corresponding microphones, and then are collected. A processor 20 digitizes respective signals from the plurality of the microphones and acquires band levels which are levels for respective bands from respective data sequences. An interpolation computing part 26 interpolates the band levels among the data sequences, referring to distances of the sound source collecting positions, so that an image including a two-dimensional band level in the sound source survey region is generated for each band based on the data sequences and the interpolated data. COPYRIGHT: (C)2004,JPO

Sound collecting device and sonic wave analyzing system

The invention discloses an MEMS device residual stress temperature characteristic measuring method. The method comprises the steps that a mechanical structure of an MEMS device and a two-end-fixed tuning fork resonator are integrated on a same chip, due to the fact that the frequency of the two-end-fixed tuning fork resonator and the axial stress of a beam of the two-end-fixed tuning fork resonator have the relevancy, residual stress under different temperatures is obtained by testing the frequencies of the two-end-fixed tuning fork resonator under different temperatures, and therefore the residual stress temperature characteristic is obtained. The measuring method is simple, and capable of measuring the temperature characteristic of the residual stress produced in the MEMS technology and the temperature characteristic of the residual stress produced by packaging each working procedure; in the residual stress temperature characteristic measuring process, the packaged structure does not need to be disassembled, and the MEMS device will not be damaged.

MEMS device residual stress temperature characteristic measuring method

PURPOSE:To provide the sound source observation use sound image visualizing device by which a sound source is surely observed with simple configuration, the sound image is visualized and which is used for maintenance of an observation object. CONSTITUTION:The system is provided with an observation object having a sound source, a parabolic reflector 1 opposed to the observation object, a microphone array 2 arranged to a focal plane of the parabolic reflector 1, and a display device converting a spatial distribution of sound pressure in front of the parabolic reflector 1 into a 2-dimension picture continuously based on an output signal of the microphone array 2.

Sound image visualizing device for sound source observation

PURPOSE:To find the defect of a structure to be measured so as to judge the soundness of the structure by heating the structure and measuring the temperature change of the structure. CONSTITUTION:A structure 1 to be measured is heated with a heating device. The heating device can be an infrared lamp or heating wire and no such a device as the burner, etc., which generates a high temperature is required. After heating the structure 1, the surface temperature of the structure 1 is measured with a radiation thermometer 3. The temperature measured with the thermometer 3 is analyzed by means of a radiation thermometer data analyzing device and the analyzed results are displayed on a display device 5 in real time and, at the same time, recorded in a storage device 6. A defective part can be roughly pointed out from the difference between the temperatures displayed on the display device 5 and, in addition, the defective part can be specified by calculating the temperature variation from the data recorded in the storage device 6.

Method for judging soundness of structure

PURPOSE:To easily judge the occurrence of ground liquefaction for entire ground. CONSTITUTION:The microtremors of ground are measured as to horizontal two-directional components that orthogonally intersect each other and a vertical component, and the ratios of the Fourier spectrum of one component to that of another are calculated. The characteristic of the spectrum ratio shows the vibration characteristic of the ground; in the case of hard ground it becomes almost one over the entire frequency bands; in the case of ground with contract in hardness a certain frequency band is predominant. In the case of such ground that could undergo liquefaction, the spectrum ratio is less than one in frequency bands higher than a definite dominant frequency, or does not show any define dominant frequency and in that case it is far below one over a wide frequency band. Thus the occurrence of ground can be detected according to whether or not the spectrum ratio calculated is less than one over a wide band. Also, the degree of liquefaction can be determined according to the extent of the range wherein the spectrum ratio is less than one.

Method for judging ground liquefaction

PURPOSE:To measure water level continuously and accurately by determining the pipe length above the water surface based on the sound in the pipe picked up through a microphone. CONSTITUTION:Sound in a pipe 2 is picked up through a microphone 1 and delivered to an input unit 5 at a data processing section 4. Data is delivered with very short duration from the input unit 5 through two Fourier transform units 6, 6 to a surpass period interval operating unit 7 where a surpass period interval 4t is operated and fed to a pipe length operating unit 8. The pipe length operating unit 8 determines a pipe length l from the interval DELTAt and a sound speed (v) according to a formula l=DELTAt.v/2. A water level operating unit 9 determines a water level based on the pipe length l thus operated and produces information or alarm as required.

Water level gage

PURPOSE:To observe a sound generated within a natural slope, an earth structure or the like at all times, and grasp continuously and linearly changes generated in the slope, structure or the like, and the vicinity thereof by burying underground a tube with microphones continuously fitted. CONSTITUTION:An underground sound sensor 9 comprising a plurality of microphones 2 preliminarily fitted to a tube 1 is buried in a natural slope and under an earth structure or the like. Signals from the microphones are transmitted to the input device 5 of an observation center 4 via a transmission line 3. The input device 5 receives the signals from the microphones 2, and transmits the vibration information of each microphone 2 to a sampling device 6. A mean amplitude calculation device 7 always calculates the mean amplitude of each microphone 2, on the basis of information from the sampling device 6, and transmits the result of the calculation to a disaster position determination device 8. This device 8 detects a microphone 2 having a maximum mean amplitude and another microphone 2 adjacent thereto and having the second largest mean amplitude. Then, the device 8 specifies a disaster position and predicts the occurrence of a disaster, on the basis of a ratio of mean amplitudes Also, the device 8 issues information and a warning, depending upon a circumstance.

Saida Atsushi

Papers

Sound image visualizing device for sound source observation

Method for judging soundness of structure

Method for judging ground liquefaction

Water level gage

Underground sound sensor