Abnormal sound detection system and abnormal sound detection method

Abstract

To provide a system which detects an allophone even in a noisy place and estimates the position of generation of an allophone.SOLUTION: An allophone detection system includes a sound collecting-detecting device and an acoustic signal analyzer. The sound collecting-detecting device includes: a sound collecting unit for collecting external sound; a positioning unit for positioning positional information of the position where sound was collected; and a communication unit for sending the acoustic data and the positional information. The acoustic signal analyzer includes: a reception unit for receiving the acoustic data and the positional information sent from the communication unit; an acoustic signal analysis unit for performing a frequency analysis of the acoustic data and calculating spectrum data of an evaluation target; an allophone determination unit for comparing the spectrum data of the evaluation target in a predetermined frequency region and spectrum data in a predetermined normal time, thereby determining whether the acoustic data includes an allophone; and a position estimation unit for estimating the position of generation of an allophone on the basis of positional information in which acoustic data which has been determined to include an allophone is collected when the allophone determination unit has determined that the acoustic data includes an allophone.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an abnormal sound detection system and an abnormal sound detection method. [Background technology]

[0002] Engineers working in plants and factories such as refineries may hear unusual sounds in the operation of equipment while working and detect abnormalities in the equipment. However, some plants and factories are equipped with high-noise sources such as compressors, and when the noise level exceeds 85 dB, for example, engineers wear noise protection equipment such as earplugs and earmuffs. Wearing noise protection equipment makes it difficult for even experienced engineers to hear abnormal noises emitted by the equipment.

[0003] Patent Document 1 discloses a system for identifying the cause of an abnormal noise (for example, a component of a vehicle such as an engine or drivetrain). This system generates FFT data by performing an FFT (Fast Fourier Transform) on sound pressure data containing the abnormal noise, and performs statistical analysis to calculate the degree of abnormality. The system then creates integrated FFT data by integrating FFT data with an abnormality degree equal to or greater than a threshold, and identifies the cause of the abnormal noise by comparing the integrated FFT data with clusters that have been clustered for each abnormality cause. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-081364 Summary of the Invention [Problem to be solved by the invention]

[0005] In plants and factories, there is a need for a method to detect abnormal sounds and identify the source of the noise, even in high-noise environments.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an abnormal sound detection system and an abnormal sound detection method that can solve the above-mentioned problems. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, an abnormal sound detection system includes a sound collection and detection device and an acoustic signal analysis device. The sound collection and detection device has a sound collection unit that collects external sounds and outputs the collected sounds as acoustic data, a positioning unit that measures position information of a position where the sound is collected, and a communication unit that transmits the acoustic data and the position information measured by the positioning unit. The acoustic signal analysis device has a receiving unit that receives the acoustic data and the position information transmitted by the communication unit, an acoustic signal analysis unit that performs frequency analysis on the acoustic data to calculate spectrum data of an object to be evaluated, an abnormal sound determination unit that determines whether the acoustic data includes an abnormal sound by comparing the spectrum data of the object to be evaluated in a predetermined frequency domain with predetermined spectrum data in a normal state, and a position estimation unit that, if it is determined that an abnormal sound is included, estimates the position of occurrence of the abnormal sound based on the position information of the position where the acoustic data determined to include an abnormal sound was collected.

[0008] According to one aspect of the present disclosure, an abnormal sound detection method includes the steps of receiving acoustic data of collected external sound and positional information of the position where the sound was collected; calculating spectrum data of an object to be evaluated by frequency analyzing the acoustic data; determining whether the acoustic data includes an abnormal sound by comparing the spectrum data of the object to be evaluated in a predetermined frequency range with predetermined spectrum data in a normal state; and, if it is determined in the determining step that an abnormal sound is included, estimating the position where the abnormal sound is occurring based on the positional information of the position where the acoustic data determined to include an abnormal sound was collected. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to detect abnormal noise even in high noise environments and estimate the location where the abnormal noise is occurring. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of an abnormal sound detection system according to an embodiment. [Figure 2] FIG. 1 is a block diagram illustrating an example of an abnormal sound detection system according to an embodiment. [Figure 3] FIG. 4 is a diagram showing an example of spectrum data of area A according to the embodiment. [Figure 4] FIG. 4 is a diagram showing an example of time-series spectrum data of area A according to the embodiment. [Figure 5] FIG. 10 is a diagram showing an example of spectrum data in area B according to the embodiment. [Figure 6] FIG. 10 is a diagram showing an example of spectrum data of the C area according to the embodiment. [Figure 7] FIG. 10 is a diagram showing an example of spectrum data of the D area according to the embodiment. [Figure 8] FIG. 10 is a diagram showing an example of spectrum data when an abnormal noise occurs according to the embodiment. [Figure 9A] FIG. 1 is a first diagram illustrating the process of estimating the abnormal noise generation position according to the embodiment. [Figure 9B] FIG. 2 is a second diagram illustrating the process of estimating the abnormal noise generation position according to the embodiment. [Figure 10] 10 is a flowchart illustrating an example of an abnormal sound detection process according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] <Embodiment> (System Configuration) An abnormal sound detection system according to an embodiment of the present disclosure will be described below with reference to FIGS. 1 to 10 . FIG. 1 is a schematic diagram illustrating an example of an abnormal sound detection system according to an embodiment. The abnormal sound detection system 100 uses a sound collection and detection device 10 worn by a worker M working in a facility G, such as a plant or factory, to collect acoustic data at various locations in the facility G, determine whether an abnormal sound is occurring, and, if an abnormal sound is occurring, estimate where in the facility G the abnormal sound is coming from. The abnormal sound detection system 100 includes the sound collection and detection device 10, a wireless communication device 5, a network NW, an acoustic signal analysis device 20, a display device 30, and an external storage device 40. The sound collection and detection device 10 is incorporated into noise protection equipment, such as earplugs or earmuffs, worn by the worker M. Alternatively, the sound collection and detection device 10 may be attached to an armband or work clothes worn by the worker M, or may be incorporated into a wristwatch, tool, or various devices carried by the worker M. Furthermore, detection of sounds, including abnormal sounds, may be performed by sound collection and detection devices 10 worn by multiple workers M working in various locations within facility G, or by sound collection and detection devices 10 worn by workers M patrolling within facility G for monitoring, transporting materials, etc. Furthermore, in addition to being worn by workers M, the sound collection and detection devices 10 may also be attached to a mobile object, such as a transport device used for monitoring, transporting, etc. The sound data collected by the sound collection and detection devices 10 is transmitted to the sound signal analysis device 20 via the wireless communication device 5 and the network NW. The sound signal analysis device 20 receives the transmitted sound data and performs frequency analysis, such as FFT (fast Fourier transform), to determine whether the sound data contains abnormal sounds. If abnormal sounds are detected, the sound signal analysis device 20 estimates the source of the abnormal sounds. The sound signal analysis device 20 then outputs the estimated location of the abnormal sounds to the display device 30. For example, facility G has areas A to D as shown in the figure, and the acoustic signal analysis device 20 determines whether an abnormal sound is occurring by comparing it with sounds collected in the vicinity of areas A to D under normal conditions, and if an abnormal sound is occurring, estimates the location where the abnormal sound is occurring based on acoustic data collected at multiple locations.As an example, the following explanation will be given using an example of detecting abnormal sounds based on sounds collected near areas A to D, but there is no need to limit the area; the abnormal sound detection system 100 can detect abnormal sounds by comparing them with sounds generated under normal conditions from any location in facility G, and identify the location of their generation.

[0012] FIG. 2 is a block diagram illustrating an example of an abnormal sound detection system according to the embodiment. The sound collection and detection device 10 includes a sound collection unit 11, a communication unit 12, and a positioning unit 13. The sound collection unit 11 collects surrounding sounds and outputs the collected sounds as acoustic data (electrical signals). The sound collection unit 11 is, for example, a microphone. The communication unit 12 is a communication module that enables wireless communication such as Wi-Fi (registered trademark) or wireless LAN. The positioning unit 13 includes, for example, a GNSS (Global Navigation Satellite System) receiver and measures position information of the sound collection and detection device 10. The positioning unit 13 may acquire position information using an RFID (Radio Frequency Identifier) ​​tag. The positioning unit 13 may acquire position information based on signal strength from wireless communication devices such as Wi-Fi (registered trademark) or wireless LAN. Alternatively, the positioning unit 13 may acquire position information by incorporating a gyro, acceleration sensor, and an autonomous navigation calculation module. The sound collection and detection device 10 transmits the acoustic data collected by the sound collection unit 11 and the position information of the sound collection and detection device 10 determined by the positioning unit 13 to the acoustic signal analysis device 20 using the communication unit 12 at a predetermined control period.

[0013] The wireless communication device 5 mediates communication between the sound collection and detection device 10 and the acoustic signal analysis device 20. For example, the wireless communication device 5 may include an access point (AP) capable of communicating with the sound collection and detection device 10 and a router capable of communicating with the acoustic signal analysis device 20. The wireless communication device 5 may communicate directly with the sound collection and detection device 10, or may communicate with the sound collection and detection device 10 via a mobile terminal such as a smartphone connected to the sound collection and detection device 10 via Bluetooth (registered trademark). The sound collection and detection device 10 communicates with the acoustic signal analysis device 20 present on a network NW such as the Internet via the wireless communication device 5. Specifically, the sound collection and detection device 10 transmits acoustic data and location information to the acoustic signal analysis device 20.

[0014] The acoustic signal analysis device 20 is configured by a server device and includes a receiving unit 21, an input unit 22, a control unit 23, and a storage unit . The receiving unit 21 receives the acoustic data and position information transmitted by the sound collection and detection device 10, and records these in the storage unit 28 in association with the time of reception. The input unit 22 is configured using input devices such as a keyboard, a mouse, a touch panel, buttons, etc., and accepts user operations using the input devices. For example, the input unit 22 accepts settings regarding which frequency range of the spectrum obtained by FFT analysis of acoustic data should be focused on for abnormal sound detection. The control unit 23 analyzes the acoustic data collected from the sound collection and detection device 10, and controls the process of detecting abnormal sounds and the process of estimating the position where the abnormal sound is occurring. The control unit 23 includes an acoustic signal analysis unit 24, an abnormal sound determination unit 25, a position estimation unit 26, and an output unit 27. The acoustic signal analysis unit 24 performs frequency analysis on the acoustic data received by the receiving unit 21 using FFT or the like, and records the analyzed spectrum data in the storage unit . The abnormal sound determination unit 25 compares the spectrum data calculated by the acoustic signal analysis unit 24 with the spectrum of the sound emitted from each area of ​​the facility G, and determines whether or not the acoustic data contains an abnormal sound. The position estimation unit 26 estimates the location where the abnormal sound has occurred, using spectrum data that has been determined to contain an abnormal sound by the abnormal sound determination unit 25. For example, the position estimation unit 26 estimates the location where the abnormal sound has occurred by a three-point positioning method, based on acoustic data collected by the sound collection and detection device 10 at least three positions. The output unit 27 outputs the determination result by the abnormal sound determination unit 25 and the abnormal sound generation position estimated by the position estimation unit 26 to the display device 30. The storage unit 28 stores various data received by the receiving unit 21, spectrum data calculated by the acoustic signal analysis unit 24, normal spectrum data by area used by the abnormal sound detection unit 25 to detect abnormal sounds, and the like.

[0015] The display device 30 is configured using a liquid crystal display or the like, and is connected to the acoustic signal analysis device 20. The display device 30 displays the information output by the output unit 27. The external storage device 40 is a storage device provided outside the acoustic signal analysis device 20. The external storage device 40 may be provided in a so-called cloud computing system. The acoustic signal analysis device 20 and the external storage device 40 can communicate with each other via a network NW, and the acoustic signal analysis device 20 can record data in the external storage device 40 and read data from the external storage device 40. In the abnormal sound detection system 100, the external storage device 40 can be used in place of the storage unit 28. For example, the receiving unit 21 of the acoustic signal analysis device 20 may record various received data in the external storage device 40. The acoustic signal analysis unit 24 of the acoustic signal analysis device 20 may record calculated spectrum data in the external storage device 40. The external storage device 40 may also store normal spectrum data for each area. In the following description, the storage unit 28 is used as an example to record various data, but the external storage device 40 can be used in place of the storage unit 28.

[0016] (Method of detecting abnormal noise) In each of areas A to D of facility G, sounds with a spectrum specific to that area are output, even under normal conditions. Spectrum data of sound collected in each area under normal conditions (when no abnormal sounds are occurring) is pre-registered in memory unit 28 as reference data to be used for comparison. Abnormal sound determination unit 25 compares the normal spectrum data prepared for each area with spectrum data obtained by analyzing the sound data transmitted from sound collection and detection device 10 to detect abnormal sounds. Examples of spectrum data for each area under normal conditions are shown in FIGS. 3 to 8. The vertical axis of the graphs shown in FIGS. 3 to 8 indicates the sound pressure level (dB), and the horizontal axis indicates the frequency (kHz).

[0017] 3 is a diagram showing an example of spectrum data for area A according to the embodiment. Fig. 3 shows spectrum data w0 obtained from acoustic data collected in area A at a certain time. Box w1 shows the waveform in the frequency range above 600 kHz, and box w2 shows the peak value in the frequency range above 600 kHz.

[0018] FIG. 4 is a diagram showing an example of time-series spectrum data for area A according to the embodiment. FIG. 4 shows spectrum data w0 obtained from acoustic data collected in area A from times t1 to t7. As in FIG. 3, boxes w1 and w2 each show the waveform and peak values ​​in the frequency range of 600 kHz or higher. As shown in FIG. 4, in the frequency range below 600 kHz, the waveform changes significantly over time. In contrast, in the frequency range above 600 kHz, the waveform fluctuates little over time, and the peak values ​​and the frequencies at which the peak values ​​appear remain almost unchanged.

[0019] Similarly, Figures 5 to 7 each show an example of spectrum data w0 for areas B to D under normal conditions. In each figure, box w1 shows the waveform in the frequency region above 600 kHz, and box w2 shows the peak value. Although not shown, analysis results similar to those described using Figure 4 have been confirmed for areas B to D. That is, even in areas B to D, the waveform fluctuates significantly over time in the frequency region below 600 kHz, but fluctuates little over time in the frequency region above 600 kHz. Furthermore, the peak value and the frequency at which the peak value appears do not change. In other words, because the waveform fluctuates significantly in the frequency region below 600 kHz even under normal conditions, it is difficult to determine whether or not an abnormal noise is occurring by focusing on this frequency region. Conversely, if we focus on the frequency region above 600 kHz, where waveform fluctuation is minimal, and a change in the waveform occurs in this frequency region, we can conclude that an abnormal noise is occurring.

[0020] As described above, it is known that in each of areas A to D, the waveform fluctuates significantly in the frequency range below a predetermined value (600 kHz in this example), while there is little change in the waveform and peak value in the range above that frequency. Utilizing this property, this embodiment focuses on the frequency range above a predetermined value (e.g., 600 kHz), and if a waveform fluctuation not observed under normal conditions occurs in this frequency range, it is determined that an abnormal sound has occurred. Examples of waveform fluctuation not observed under normal conditions include a change in the frequency at which peak values ​​appear, or an increase in overall sound pressure to the point where peak values ​​are hidden (generally, when an abnormal sound occurs due to an equipment malfunction, the sound does not become quieter, but rather becomes louder). The abnormal sound determination unit 25 compares the waveform of the spectrum data of the acoustic data transmitted from the sound collection and detection device 10 with the waveform of the spectrum data of areas A to D under normal conditions, limited to the predetermined frequency range, and determines whether the acoustic data transmitted from the sound collection and detection device 10 contains an abnormal sound. In this example, we have uniformly focused on the frequency range above 600 kHz, but the frequency range focused on for each area may be different, such as 600 kHz or above for area A, 500 kHz or above for area B, etc.

[0021] (Example of abnormal noise) FIG. 8 shows an example of spectrum data of acoustic data collected when an abnormal sound occurs in area C. As in FIGS. 3 to 7, w0 represents spectrum data, w1 represents a frequency range above 600 kHz, and w2 represents the frequency at which a peak value appears. Furthermore, waveform w0' in FIG. 8 shows the spectrum of acoustic data collected at a certain time when a malfunction occurs in a device in area C. As shown in the figure, spectrum data w0' exceeds normal spectrum data w0 in the frequency range above 600 kHz, and the frequency components within frame w2 of spectrum data w0' exceed the normal peak value. Furthermore, unlike normal times, peak values ​​are observed in the frequency range indicated by frame w2' in spectrum data w0'. When a waveform state different from normal times occurs, such as when peak values ​​appear in a frequency range different from normal times or when the sound pressure in the frequency range of interest (within frame w1) increases overall compared to normal times (the sound becomes louder in the treble range), the abnormal sound detector 25 determines that an abnormal sound has occurred.

[0022] (Estimation of the location of the abnormal noise) Next, we will explain the process of estimating the location of an abnormal sound when it is determined that an abnormal sound has occurred. As shown in FIG. 9A , assume that an abnormal sound is detected in the acoustic data collected by the sound collection and detection device 10 when a worker M patrolling within facility G is located at points a, b, and c. Then, the position estimation unit 26 estimates the location of the abnormal sound by triangulation using the location information of points a, b, and c. The triangulation method is a well-known algorithm used, for example, in situations where the location of a terminal transmitting radio waves is calculated based on the radio wave strength measured by three wireless LAN access points. By replacing the radio wave strength in this algorithm with sound pressure level, the location of the abnormal sound can be estimated using the triangulation method. For example, the location information of point a is (p1, q1), the location information of point b is (p2, q2), and the location information of point c is (p3, q3). Furthermore, let the position information of the abnormal sound source be (x, y), the distance between point a and the abnormal sound source be R1, the distance between point b and the abnormal sound source be R2, and the distance between point c and the abnormal sound source be R3. Then, the following equations (1) to (3) are established as shown in Figure 9B. (x-p1) 2 +(y-q1) 2 =R1 2 ···(1) (x-p2) 2 +(y-q2) 2 =R2 2 ···(2) (x-p3) 2 +(y-q3) 2 =R3 2 ···(3)

[0023] (p1, q1), (p2, q2), and (p3, q3) are known because they are measured by the sound collection and detection device 10. Therefore, if R1 to R3 are known, the position information (x, y) of the abnormal sound source can be found using equations (1) to (3). R1 ​​to R3 are calculated, for example, as follows. Generally, if the sound level measured at a point r1 (m) (for example, r1 = 1 (m)) from a noise source is Lr1 (dB), and the sound level measured at a point r2 (m) from the noise source is Lr2 (dB), then the following equation (4) holds. Noise attenuation (Lr1-Lr2)=10·log 10 (r1 / r2) (4) Solving equation (4) for Lr2 gives the following equation (4'). Lr2=Lr1-10 log 10 (r1 / r2) =Lr1-10·(log e (r1 / r2) / log 10 )···(4´) Let the sound pressure level (dB) of the abnormal sound detected at each of points a through c be noise Lr2 (dB), and let the distance between each of points a through c and the location where the abnormal sound is occurring be r2 (i.e., R1, R2, and R3, respectively). Equation (4') is obtained for each of points a through c. From these three equations (4'), R1, R2, and R3 are calculated so that Lr1 is equal. Then, using equations (1) through (3) above, the approximate range where the abnormal sound source (x, y) is located can be estimated. Point P in Figure 9A is an example of the location of the abnormal sound estimated using triangular positioning. In this way, the location of the abnormal sound can be estimated by collecting sound data at various locations in facility G and analyzing the collected sound data.

[0024] (operation) Next, the abnormal sound detection process of this embodiment will be described with reference to Fig. 10. As mentioned above, the following description will also be given taking as an example a case where the storage unit 28 is used as the data recording destination, but the external storage device 40 may be used instead of the storage unit 28. FIG. 10 is a flowchart illustrating an example of the abnormal sound detection process according to the embodiment. As a premise, the memory unit 28 stores normal spectrum data for each area, as exemplified in FIGS. 3 and 5 to 7. The normal spectrum data may be updated, for example, by spectrum data obtained by frequency analysis of the acoustic signal analyzer 24 using acoustic data detected by the sound collection and detection device 10 near each of areas A to D while the worker M is patrolling the facility G daily. Alternatively, the normal spectrum data may be selected by an engineer from among the spectrum data obtained by frequency analysis of the acoustic signal analyzer 24. The frequency range of interest (e.g., 600 kHz or higher) and the frequency of the peak value in that frequency range may be set by an engineer with expertise. Alternatively, the acoustic signal analyzer 24 may analyze the time-dependent fluctuations in normal spectrum data obtained over a predetermined period of time to detect and automatically set the frequency range in which the waveform fluctuations fall within a predetermined range, the peak value in that frequency range, and the frequency at which the peak value appears. Information on normal spectrum data for each area, the frequency range of interest, the peak value, and the frequency at which the peak value appears is registered in the memory unit 28.

[0025] Furthermore, worker M wearing sound collection and detection device 10 periodically patrols facility G, measuring acoustic data and location information at various locations in facility G. Sound collection and detection device 10 pairs acoustic data and location information measured at the same time (the same time period that can be considered the same time) and transmits them in real time to acoustic signal analysis device 20. These data are transmitted to acoustic signal analysis device 20 via network NW. In parallel with the measurement and transmission of acoustic data, etc. by sound collection and detection device 10, the following processing is repeatedly executed at a predetermined control cycle on the acoustic signal analysis device 20 side.

[0026] In the acoustic signal analysis device 20, when the receiving unit 21 receives a set of acoustic data and position information (step S1), it associates these with the reception time and records them in the storage unit 28. Next, the acoustic signal analysis unit 24 performs frequency analysis on the recorded acoustic data using FFT or the like (step S2), and records the spectrum data of the analysis result (referred to as spectrum data to be evaluated) in the storage unit 28 in association with the acoustic data, position information, and reception time information. Next, the abnormal sound determination unit 25 determines whether or not the acoustic data contains an abnormal sound (step S3). The abnormal sound determination unit 25 compares the spectrum data to be evaluated with normal spectrum data to determine whether or not the received acoustic data contains an abnormal sound (detects an abnormal sound). For example, the abnormal sound determination unit 25 compares a region above a predetermined frequency (for example, 600 kHz or above) in any of the spectrum data for areas A to D when normal, or in a waveform obtained by combining multiple pieces of spectrum data for areas A to D when normal, with the same frequency region in the spectrum data to be evaluated, and if the waveform shape, sound pressure level, peak value magnitude, and frequency at which the peak value appears match, or if the difference between the two falls within a predetermined range that can be considered to match, it determines that no abnormal sound is included in the sound data transmitted from the sound collection and detection device 10. Furthermore, if, as a result of the comparison, the spectrum data to be evaluated does not match in characteristics with either the spectrum data for areas A to D when normal, or the waveform data obtained by combining multiple pieces of spectrum data for areas A to D when normal, the abnormal sound determination unit 25 determines that the spectrum data to be evaluated includes an abnormal sound. For example, if the value obtained by subtracting the average sound pressure level in a frequency range of interest of the spectrum data of each area under normal conditions from the average sound pressure level in a frequency range of interest of the spectrum data of the evaluation target is equal to or greater than a predetermined threshold, or if a peak value appears at a frequency that does not appear in the spectrum data of each area under normal conditions, the abnormal sound detector 25 determines that the spectrum data of the evaluation target contains an abnormal sound. If it is determined that an abnormal sound is contained, the abnormal sound detector 25 records flag information indicating that an abnormal sound has been detected in the storage unit 28, in association with the spectrum data, acoustic data, reception time information, and location information containing the abnormal sound.Furthermore, the abnormal sound determination unit 25 associates the sound pressure (dB) of the peak value detected in the frequency range of interest with spectrum data containing the abnormal sound, etc., and records it in the storage unit 28. The sound pressure of the peak value is used as Lr2 (dB) in the above-mentioned three-point positioning method.

[0027] If the abnormal sound determination unit 25 determines that no abnormal sound is included (step S4; No), the output unit 27 outputs information such as "normal" or "no abnormal sound detected" to the display device 30 together with information on the position and time (reception time) at which the acoustic data was collected (step S7).

[0028] If the abnormal sound determination unit 25 determines that an abnormal sound is included (Step S4; Yes), the position estimation unit 26 performs position estimation. First, the position estimation unit 26 searches to see if a total of three or more pieces of spectrum data and peak sound pressure values, acoustic data, location information, and reception time information, each with flag information indicating that an abnormal sound has been detected, are recorded in the storage unit 28. At this time, only acoustic data collected within a predetermined time period based on the reception time information of the acoustic data determined in Step S3 to contain an abnormal sound may be considered (for example, data from several days ago may be excluded because it is determined to be too old and different from the currently detected abnormal sound), or the range of location information may be limited (for example, acoustic data containing an abnormal sound collected from a position only a few meters away a few seconds ago may be excluded because it is not very useful for use in triangulation calculations). If three or more pieces of acoustic data with flag information indicating that an abnormal sound has been detected cannot be found, including the acoustic data determined to contain an abnormal sound in step S3 (step S5; No), position estimation using the triangular positioning method is not possible. Therefore, for example, a supervisor or other person monitoring using the acoustic signal analyzer 20 instructs worker M to collect more acoustic data. Worker M patrols facility G and measures acoustic data and position information using the sound collection and detection device 10. The sound collection and detection device 10 transmits the acoustic data and position information to the acoustic signal analyzer 20, and the processing from step S1 onwards is repeatedly executed until acoustic data determined to contain an abnormal sound is collected at three or more locations. At this time, the output unit 27 may output to the display device 30 that an abnormal sound has been detected, that there is insufficient data indicating that an abnormal sound has been detected, and the position information of the locations where the abnormal sound has been detected that has been obtained so far. Upon seeing this output, the supervisor may instruct worker M on site to go to an appropriate location and collect acoustic data using the sound collection and detection device 10.

[0029] If data determined to contain an abnormal sound exists at three or more points (Step S5; Yes), the position estimation unit 26 estimates the location of the abnormal sound by triangulation using acoustic data detected at three different points (Step S6). With triangulation, if the location of the abnormal sound does not lie within the area surrounded by the three selected points, no solution is found. Therefore, the acoustic data determined to contain an abnormal sound in Step S3 is used, and for the remaining two pieces of data, any two points may be selected from acoustic data collected at different points. Position estimation using triangulation may be repeated while varying the combination of the three points containing the data determined to contain the abnormal sound this time, thereby estimating the location of the abnormal sound. The position estimation unit 26 records the estimated location of the abnormal sound in the storage unit 28. Note that the method for estimating the location of the abnormal sound is not limited to triangulation, and other methods may be used. For example, if acoustic data containing an abnormal sound is collected around a certain area, it may be estimated that the source of the abnormal sound is roughly located in that area. Next, the output unit 27 outputs the estimated location of the abnormal sound to the display device 30 (step S7). For example, as shown in Fig. 9A, the output unit 27 may generate an image showing the three points used in the estimation and the location P of the abnormal sound on a map of facility G, and output this image to the display device 30. If multiple locations of the abnormal sound are estimated, the locations of the abnormal sounds may be displayed.

[0030] As described above, the abnormal sound detection system 100 of this embodiment is equipped with a sound collection and detection device 10 including a sound collection unit 11 for external environmental sounds, a communication unit 12, and a positioning unit 13, mounted on noise protection equipment worn by a worker. The system compares the external sounds collected by the sound collection unit 11 with normal sounds, and if there is a difference between the two, it determines that an abnormal sound has been detected. In this case, the comparison is performed focusing on frequency ranges that exhibit characteristics specific to each device and location and exhibit little fluctuation over time, thereby enabling accurate detection of abnormal sounds. Furthermore, the location of the abnormal sound can be estimated based on the location information of the location where the abnormal sound was detected, allowing for the rapid identification and treatment of abnormal occurrences within the vast facility G. Thus, according to this embodiment, abnormal sounds can be detected and their location identified early simply by the worker M wearing noise protection equipment such as earplugs while patrolling his or her usual patrol route, or by the worker M simply performing normal work in his or her workplace while wearing the noise protection equipment.

[0031] Each processing step in the sound collection and detection device 10 and the acoustic signal analysis device 20 can be realized by a processor, such as a CPU (Central Processing Unit), included in each of the sound collection and detection device 10 and the acoustic signal analysis device 20 executing a program. The programs executed by the sound collection and detection device 10 and the acoustic signal analysis device 20 may be recorded on a computer-readable recording medium and implemented by reading and executing the programs recorded on the recording medium. The sound collection and detection device 10 and the acoustic signal analysis device 20 include hardware such as an operating system (OS) and peripheral devices. The computer-readable recording medium may be, for example, a portable medium such as a flexible disk, a magneto-optical disk, a ROM (Read Only Memory), or a CD-ROM (Compact Disk Read Only Memory), or a storage device such as a hard disk built into the sound collection and detection device 10 or the acoustic signal analysis device 20. Furthermore, the computer-readable recording medium may include a recording medium that dynamically stores a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, or a recording medium that stores a program for a fixed period of time, such as a volatile memory within a computer system that serves as a server or client in such a case. Furthermore, the program may be one that realizes part of the above-mentioned functions, or may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

[0032] (Appendix 1) an abnormal sound detection system comprising a sound collection and detection device and an acoustic signal analysis device, wherein the sound collection and detection device has a sound collection unit that collects external sounds and outputs the collected sounds as acoustic data, a positioning unit that measures position information of a position where the sound is collected, and a communication unit that transmits the acoustic data and the position information measured by the positioning unit, and the acoustic signal analysis device has a receiving unit that receives the acoustic data and the position information transmitted by the communication unit, an acoustic signal analysis unit that calculates spectrum data of an object to be evaluated by performing frequency analysis on the acoustic data, an abnormal sound determination unit that determines whether the acoustic data includes an abnormal sound by comparing the spectrum data of the object to be evaluated in a predetermined frequency domain with predetermined spectrum data in a normal state, and a position estimation unit that, if it is determined that an abnormal sound is included, estimates the position where the abnormal sound is generated based on the position information of the position where the acoustic data determined to include an abnormal sound was collected.

[0033] (Appendix 2) The abnormal sound detection system according to claim 1, wherein the abnormal sound determination unit determines that the sound data contains an abnormal sound when the sound pressure level of the spectrum data to be evaluated in the predetermined frequency range is greater than the sound pressure level of the spectrum data in a normal state by a predetermined threshold or more.

[0034] (Appendix 3) The abnormal sound detection system according to claim 1 or 2, wherein the abnormal sound determination unit determines that the sound data includes an abnormal sound when a frequency of a peak value of the spectrum data to be evaluated in the predetermined frequency range differs from a frequency of a peak value of the spectrum data in a normal state.

[0035] (Appendix 4) 4. The abnormal sound detection system according to claim 1, wherein the position estimation unit estimates the position where the abnormal sound is generated by a triangular positioning method.

[0036] (Appendix 5) 5. The abnormal sound detection system according to any one of claims 1 to 4, wherein the sound collection and detection device is provided in a hearing protection device.

[0037] (Appendix 6) an abnormal sound detection method comprising the steps of: receiving acoustic data of collected external sound and positional information of the position where the sound was collected; calculating spectrum data of an object to be evaluated by frequency analyzing the acoustic data; determining whether or not the acoustic data includes an abnormal sound by comparing the spectrum data of the object to be evaluated in a predetermined frequency range with predetermined spectrum data in a normal state; and, if it is determined in the determining step that an abnormal sound is included, estimating the position where the abnormal sound is occurring based on the positional information of the position where the sound was collected in the acoustic data determined to include the abnormal sound.

[0038] In addition, the components in the above-described embodiments can be replaced with well-known components as appropriate without departing from the spirit of the present invention. Furthermore, the technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. [Explanation of symbols]

[0039] 5. Wireless communication device 10. Sound collection and detection device 11...Sound collecting section 12. Communications Department 13. Positioning unit 20...Acoustic signal analysis device 21. Receiving unit 22 Input section 23 Control unit 24. Acoustic signal analysis unit 25 Abnormal noise detection unit 26...Position estimation section 27 Output section 28...Storage section 30...Display device 40...External storage device 100···Abnormal noise detection system

Claims

1. A sound collection and detection device, an acoustic signal analyzer; Including, The sound collection and detection device is a sound collection unit that collects external sounds and outputs the collected sounds as acoustic data; a positioning unit that measures position information of a position where the sound is collected; a communication unit that transmits the acoustic data and the position information measured by the positioning unit; and The acoustic signal analysis device a receiving unit that receives the acoustic data and the position information transmitted by the communication unit; an acoustic signal analysis unit that performs frequency analysis on the acoustic data to calculate spectrum data of an object to be evaluated; an abnormal sound determination unit that determines whether the acoustic data includes an abnormal sound by comparing spectrum data of the evaluation target in a predetermined frequency range with predetermined spectrum data in a normal state; a position estimation unit that, when it is determined that an abnormal sound is included, estimates the position where the abnormal sound is generated based on the position information of the position where the acoustic data determined to include the abnormal sound was collected; and An abnormal noise detection system having:

2. the abnormal sound determination unit determines that the sound data includes an abnormal sound when a sound pressure level of the spectrum data to be evaluated in the predetermined frequency range is greater than a sound pressure level of the spectrum data in a normal state by a predetermined threshold or more. The abnormal noise detection system according to claim 1 .

3. the abnormal sound determination unit determines that the sound data includes an abnormal sound when a frequency of a peak value of the spectrum data to be evaluated in the predetermined frequency range is different from a frequency of a peak value of the spectrum data in a normal state. The abnormal noise detection system according to claim 1 or 2.

4. the position estimation unit estimates the generation position of the abnormal noise by a triangular positioning method; The abnormal noise detection system according to claim 1 or 2.

5. The sound collection and detection device is provided in hearing protection equipment. The abnormal noise detection system according to claim 1 or 2.

6. receiving acoustic data of collected external sounds and location information of the locations where the sounds are collected; a step of performing frequency analysis on the acoustic data to calculate spectrum data of an object to be evaluated; a step of determining whether or not the acoustic data includes an abnormal sound by comparing spectrum data of the evaluation target in a predetermined frequency range with predetermined spectrum data in a normal state; a step of estimating a position where an abnormal sound is generated based on the position information of the position where the sound was collected in the acoustic data determined to include an abnormal sound in the determining step; An abnormal sound detection method comprising:

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