JP6405154B2 - Alarm sound generation direction notification system - Google Patents

Description

  One aspect of the present invention relates to a warning sound generation direction notification system.

  2. Description of the Related Art Conventionally, a system for notifying a driver of the direction in which an alarm sound of an emergency vehicle is generated is known. For example, in the alarm sound generation direction notification system described in Patent Document 1, microphones having directivity are attached to the right front part, right rear part, left front part, and left rear part of the vehicle body, and these microphones are attached to these microphones. The warning sound of the emergency vehicle is recognized by comparing the input sound around the vehicle with the predetermined sound stored in the storage medium in advance. Then, the direction in which the warning sound of the emergency vehicle is generated is identified based on the ratio of the volumes detected by the four microphones, and the driver is notified of the direction in which the warning sound is generated using a visual display or the like.

JP 2000-127796 A

  In the alarm sound generation direction notification system in Patent Document 1, it is necessary to attach microphones to the right front part, the right rear part, the left front part, and the left rear part with respect to the vehicle body. . Moreover, since it is necessary to connect each microphone and the processing part which is arrange | positioned inside a vehicle and performs each process with wiring, attachment work is complicated. Furthermore, depending on the vehicle body shape, there is a possibility that the microphone cannot be attached at an appropriate position in the right front part, right rear part, left front part, or left rear part.

  Further, in the alarm sound generation direction notification system in Patent Document 1, since the positional relationship between the microphones differs depending on the vehicle body shape, the generation direction identification accuracy may be poor. In particular, when applied to a large truck, the shape of the loading platform differs greatly depending on the type of the large truck. Therefore, there is a high possibility that the microphone cannot be mounted at an appropriate position, and the direction identification accuracy may be further deteriorated. There is.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an alarm sound generation direction notifying system that is easy to attach and whose alarm sound generation direction identification accuracy hardly depends on the vehicle body shape. To do.

  An alarm sound generation direction notifying system according to an aspect of the present invention includes a housing fixed to the outer surface of a vehicle body, first and second microphones having directivity accommodated in the housing, And an identification unit for identifying the direction in which the warning sound of the emergency vehicle is generated based on the sound detected by the second microphone, and a notification unit for notifying the driver of the direction in which the warning sound is identified by the identification unit, The first microphone is arranged with directivity in front of the vehicle, the second microphone is arranged with directivity in the rear of the vehicle, and the identification unit detects with the first and second microphones Based on the difference in sound volume level, it is identified whether the direction of the alarm sound is forward or backward.

  According to this warning sound generation direction notification system, the first and second microphones are accommodated in the casing, and the mounting operation is completed if the casing is fixed to the outer surface of the vehicle. It is. In addition, since the microphone is housed close to the inside of the housing, the conventional complicated wiring work can be omitted. Furthermore, as long as the housing can be fixed to the outer surface of the vehicle, the direction of the alarm sound can be notified regardless of the mounting position, and therefore, it is possible to deal with a wide variety of vehicle body shapes. In addition, since the positional relationship between the two microphones does not change regardless of the attachment position, the identification accuracy of the direction of occurrence is unlikely to depend on the vehicle body shape. Therefore, according to this warning sound generation direction notification system, it is possible to provide a warning sound generation direction notification system that is easy to attach and whose warning sound generation direction identification accuracy is less dependent on the vehicle body shape. .

  In the warning sound generation direction notification system according to one aspect of the present invention, the identification unit is a bandpass filter having a pass band corresponding to the frequency band of the warning sound with respect to the sound detected by the first and second microphones. After performing the processing, the difference in volume level of the sound may be identified. According to this alarm sound generation direction notification system, the alarm sound generation direction identification processing is suitably performed, and the identification accuracy of the alarm sound generation direction can be improved.

  In the alarm sound generation direction notification system according to one aspect of the present invention, the vehicle may be a truck including a driver's seat part and a cargo bed part, and the housing may be fixed to a side surface of the driver's seat part. According to this warning sound generation direction notification system, even when applied to a truck having a relatively large vehicle body, the installation work is completed if the casing is fixed to the outer surface of the driver's seat, so that the installation is easy. It is. In addition, since the housing is fixed to the side surface of the driver's seat having a relatively uniform shape, rather than the loading platform that varies greatly depending on the vehicle type, the problem of the mounting position is less likely to occur. Furthermore, even when the present invention is applied to a truck having a relatively large vehicle body, the accuracy of identifying the direction of occurrence is less dependent on the vehicle body shape.

  According to the present invention, it is possible to provide an alarm sound generation direction notifying system that is easy to attach and whose alarm sound generation direction identification accuracy hardly depends on the vehicle body shape.

It is a schematic block diagram which shows the generation direction alerting | reporting system of the alarm sound which concerns on one Embodiment. It is a schematic diagram which shows the attachment state of a housing | casing. (A) is a figure which shows the position of the sound source and sound receiving point in the directivity evaluation experiment of an alarm sound, (b) is a figure which shows the result of the directivity evaluation experiment of an alarm sound. It is a block diagram which shows the process of the generation direction alerting | reporting system of an alarm sound. (A) is a circuit diagram showing a high-pass filter and an inverting amplifier, (b) is a circuit diagram showing a low-pass filter and an inverting amplifier. (A) is a circuit diagram showing a full-wave rectifier and an averaging filter, (b) is a circuit diagram showing a differential amplifier, and (c) is a circuit diagram showing an inverter and a comparator.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals are used for the same or corresponding elements, and duplicate descriptions are omitted.

  FIG. 1 is a schematic configuration diagram illustrating a warning sound generation direction notification system according to an embodiment, and FIG. 2 is a schematic diagram illustrating a mounting position of a housing. A warning sound generation direction notification system 1 shown in FIGS. 1 and 2 is a system for notifying a driver of a warning sound generation direction (arrival direction) of an emergency vehicle. It is done. An emergency vehicle is a vehicle that is equipped with a siren and performs an emergency run while sounding an alarm sound in an emergency, such as an ambulance, a fire engine, a police car, and the like. Here, the vehicle 3 is a large truck including a driver's seat portion 3A and a cargo bed portion 3B. The vehicle 3 is not particularly limited, and may be, for example, another commercial vehicle, and may be a large vehicle, a medium-sized vehicle, a normal passenger vehicle, a small vehicle, a light vehicle, or the like.

  First, referring to FIG. 3, the result of an experiment for measuring the directivity of an alarm sound for a driver of a large truck will be described. In this experiment, the sound field of the large truck T was reproduced three-dimensionally in the 4π anechoic chamber. An alarm sound of an emergency vehicle was generated around the subject (virtual driver) at the driver's seat position, and 10 subjects answered the direction in which the sound was heard. As shown in FIG. 3 (a), the sound source position S is 12 points with an angle with respect to the sound receiving point R, which is the subject's position, varied by 30 ° from 0 ° to 360 °, and the distance from the sound receiving point R. Was 5 m. The experimental order of these sound source positions S was random.

  FIG. 3B is a diagram illustrating a result of the directivity evaluation experiment. In FIG. 3B, the x-axis is the direction of the sound source (°), and the y-axis is the direction of the sound heard (°). The center of each circle indicates the angle at which the answer was made. The larger the circle radius, the greater the number of respondents. The more circles located in the vicinity of the y = x line indicated by the broken line in FIG. 3B, the more the sound source direction and the direction of the audible sound match.

  As shown in FIG. 3B, since there are many circles located in the vicinity of the broken straight line, it can be basically understood that the direction of the sound source and the direction of the sound to be heard match. On the other hand, as shown by a broken-line circle C in FIG. 3B, when a sound is emitted from the right rear side, that is, from the position of 150 ° in FIG. There are many answers indicating that sound was heard from the 30 ° or 60 ° position in a). From this, it can be seen that a driver of a large truck is highly likely to erroneously determine that the sound has been heard from the right front when the sound is coming from the right rear. That is, it is understood that it is more difficult for the driver to determine the sound arrival direction in the front-rear direction than in the left-right direction. One of the factors is considered to be that it is difficult to recognize the sound pressure difference and the time difference because the ears are attached to the left and right.

  In the above experiment, a large truck was targeted. However, even in a general vehicle, when an emergency vehicle is approaching with a warning sound during driving, the emergency vehicle is approaching from either of the front and rear directions. It is not easy for the driver to accurately determine whether the vehicle is For this reason, even if the driver recognizes the warning sound, the driver may not be able to take an appropriate action because the approach direction is unknown. As a result, for example, an emergency vehicle may get stuck behind the host vehicle. In particular, when a driver of a large truck cannot take an appropriate action, the large truck has a large vehicle body, and therefore, there is a high possibility that the emergency vehicle will be prevented from traveling as compared with a general vehicle. Therefore, in the warning sound generation direction notification system 1, the driver is notified of which direction the warning sound is generated in the front-rear direction to improve direction localization.

  The configuration of the warning sound generation direction notification system 1 will be described with reference to FIGS. 1 and 2 again. The warning sound generation direction notification system 1 includes a housing 10 fixed to the outer surface of a vehicle 3, a first microphone 20 and a second microphone 30 housed in the housing 10, and a first The circuit board 40 on which the circuit element for processing the sound detected by the microphone 20 and the second microphone 30 is mounted, and the meter 5 inside the vehicle 3, and informing the driver of the direction in which the alarm sound is generated. Part 50.

  The housing 10 is a box composed of a main body and a lid. FIG. 1 shows only the main body, and FIG. 2 shows a state where the lid is closed. The inside of the main body and the lid is filled with a breathable urethane foam or the like (not shown) for reducing wind noise (wind noise) so as to cover the first microphone 20 and the second microphone 30. Yes. The first microphone 20 and the second microphone 30 are directional microphones having sound receiving portions 21 and 31 on the distal end side, and the sound received by the sound receiving portions 21 and 31 is converted into an electrical signal and output. . As the 1st microphone 20 and the 2nd microphone 30, the thing of arbitrary shapes and sound reception characteristics is employable. The first microphone 20 and the second microphone 30 are accommodated in the housing 10 and are located in the housing 10 in a state in which the first microphone 20 and the second microphone 30 are close to each other and the sound receiving units 21 and 31 face in different directions. Is fixed. In the present embodiment, the first microphone 20 and the second microphone 30 are arranged so as to face directions different from each other by 180 °.

  The housing 10 is fixed to the side surface 4 on the oncoming vehicle side of the driver's seat portion 3A in a state where the first microphone 20 and the second microphone 30 are accommodated. Specifically, the housing 10 is in a state in which the first microphone 20 is arranged with directivity in front of the vehicle 3 and the second microphone 30 is arranged with directivity in the rear of the vehicle 3. It is fixed to the side surface 4 in such a direction. Moreover, the housing | casing 10 is being fixed to the back side of the door part 4A in the frame part 4B which is parts other than the door part 4A of the side surfaces 4. FIG. Moreover, the housing | casing 10 is being fixed above the intermediate part in the up-down direction in the frame part 4B. This is because the fixed positions of the first microphone 20 and the second microphone 30 should be made as small as possible without being affected by wind noise and tire noise (tire noise). An arbitrary method can be adopted as a fixing method for the side surface 4 of the housing 10, and examples thereof include screwing and adhesion.

  The circuit board 40 is communicably connected to the first microphone 20 and the second microphone 30 and is connected via a wiring 41 in the present embodiment. The circuit board 40 is disposed, for example, on the back side of the meter 5. As will be described later, the circuit board 40 functions as an identification unit that identifies the direction in which the warning sound of the emergency vehicle is generated based on the difference in the sound volume level detected by the first microphone 20 and the second microphone 30.

  The alerting | reporting part 50 is arrange | positioned in the meter 5 inside a vehicle, and has the 1st alerting | reporting part 51 and the 2nd alerting | reporting part 52 which were arrange | positioned along with the upper and lower sides. The 1st alerting | reporting part 51 and the 2nd alerting | reporting part 52 are comprised by LED (Light Emitting Diode), for example. The notification unit 50 is connected to the circuit board 40 so as to be communicable, and is connected via a wiring 42 in the present embodiment. In the notification unit 50, according to the result of identifying the direction in which the alarm sound is generated by the circuit board 40, when the direction in which the alarm sound is generated is forward, the upper first notification unit 51 is lit and the direction in which the alarm sound is generated is backward. If it is, the lower second notification unit 52 is lit. Accordingly, the driver is notified whether the direction in which the warning sound is generated is forward or backward.

  Next, processing by the alarm sound generation direction notification system 1 will be described with reference to FIGS. 4 to 6.

  FIG. 4 is a block diagram showing processing of the alarm sound generation direction notification system 1. As shown in FIG. 4, in the alarm sound generation direction notification system 1, a predetermined process is performed on the circuit board 40 on the sound detected by the first microphone 20 and the second microphone 30, and the sound is detected according to the processing result. The first notification unit 51 and the second notification unit 52 are turned on / off.

  Specifically, in the circuit board 40, first, band-pass filter processing 61 is performed on each sound (output signal) detected by the first microphone 20 and the second microphone 30. In the band pass filter process 61, a high pass filter process 62 (HPF: High-Pass Filter), an inverting amplification process 63 (AMP: Amplifier amplification process), a low pass filter process 64 (LPF: Low-Pass Filter), and an inverting amplification process. Processing 65 is performed in this order (in FIG. 4, these processing blocks are connected in this order). In this process, the wind noise is first reduced by the high-pass filter process 62 and the signal reduced by the inversion amplification process 63 is amplified. The inverting amplification process 63 and the inverting amplification process 65 are processes for adjusting the output level after the filter process.

  FIG. 5 shows a circuit example for realizing the high-pass filter process 62, the inverting amplification process 63, the low-pass filter process 64, and the inverting amplification process 65. FIG. 5 shows a positive feedback secondary high-pass filter and low-pass filter using a voltage follower. Each sound detected by the first microphone 20 and the second microphone 30 is input to point A in FIG. Two points B in FIG. 5 are connected to each other. In the present embodiment, considering the main frequency band component of the warning sound of the emergency vehicle, the lower limit frequency in the high-pass filter process 62 is 500 Hz, and the upper limit frequency in the low-pass filter process 64 is 3.15 kHz. That is, the lower limit value of the passband by the bandpass filter processing 61 is 500 Hz, and the upper limit value is 3.15 kHz. This is because the main frequency band component of the warning sound of the emergency vehicle is included in the pass band, and the warning sound of the emergency vehicle is extracted without being affected by wind noise caused by traveling. As described above, in the alarm sound generation direction notification system 1, the band-pass filter processing 61 of the pass band corresponding to the frequency band of the alarm sound is performed on the sound detected by the first microphone 20 and the second microphone 30. Has been given.

  As shown in FIG. 4, after the band pass filter process 61 is performed, the output signals are each subjected to a rectification process 66 and a smoothing process 67 (average value filter process) to obtain a DC signal (analog signal) having a predetermined voltage value. ). A circuit example for realizing the rectification process 66 and the smoothing process 67 is shown in FIG. FIG. 6A shows an example in which a full-wave rectifier and an averaging filter are connected. The point C in FIG. 6 (a) is connected to the point C in FIG. 5 (b).

  Subsequently, as shown in FIG. 4, a differential amplification process 68 is performed on the smoothed output signal on the first microphone 20 side and output signal on the second microphone 30 side. A circuit example for realizing the differential amplification processing 68 is shown in FIG. The output signal on the first microphone 20 side is input to point D in FIG. 6B, and the output signal on the second microphone 30 side is input to point E in FIG. 6B. As a result, the voltage difference between the output signal on the first microphone 20 side and the output signal on the second microphone 30 side is amplified and output as one differential amplification output. In other words, the difference between the sound volume levels detected by the first microphone 20 and the second microphone 30 is output as a differential amplification output.

  The differentially amplified output is subjected to comparator processing 70 on the first notification unit 51 side and output to the first notification unit 51, and inversion processing 69 and comparator processing 70 are performed on the second notification unit 52 side. And output to the second notification unit 52. An example of a circuit that realizes the inversion processing 69 and the comparator processing 70 is shown in FIG. In the comparator processing 70, the differential amplified output or the inverted differential amplified output is compared with the threshold voltage. The reason for this is to prevent flickering. As a result of the comparison, when the voltage of the differential amplification output is larger, the first notification unit 51 is turned on. Further, when the voltage of the inverted differential amplification output is higher, the second notification unit 52 is lit.

  Through the series of processes described above, based on the difference in sound volume level detected by the first microphone 20 and the second microphone 30, it is identified whether the direction in which the alarm sound is generated is forward or backward. The first notification unit 51 is turned on when the direction in which the warning sound is generated is forward, and the second notification unit 52 is turned on when the direction in which the warning sound is generated is backward. Thereby, the driver | operator can identify the generation direction of the warning sound of an emergency vehicle by visually recognizing lighting of the 1st alerting | reporting part 51 or the 2nd alerting | reporting part 52. FIG.

  According to the alarm sound generation direction notifying system 1 described above, the first microphone 20 and the second microphone 30 are accommodated in the casing 10, and are attached if the casing 10 is fixed to the side surface 4 of the vehicle 3. Since the work is completed, the installation is easy. In addition, since the first microphone 20 and the second microphone 30 are accommodated in the housing 10 in the vicinity, a complicated wiring work as in the past can be omitted. Furthermore, as long as the housing 10 can be fixed to the side surface 4 of the vehicle 3, the direction in which the alarm sound is generated can be notified regardless of the mounting position, so that it is possible to deal with a wide variety of vehicle body shapes. In addition, since the positional relationship between the first microphone 20 and the second microphone 30 is the same regardless of the mounting position, the identification accuracy of the generation direction hardly depends on the vehicle body shape. Therefore, according to the warning sound generation direction notification system 1, it is possible to provide a warning sound generation direction notification system that is easy to attach and whose warning sound generation direction identification accuracy is less dependent on the vehicle body shape. .

  In addition, according to the alarm sound generation direction notification system 1, the band detected by the first microphone 20 and the second microphone 30 is subjected to bandpass filter processing in the pass band corresponding to the frequency band of the alarm sound. Then, since the difference in volume level of the sound is identified, the process for identifying the direction in which the alarm sound is generated is suitably performed, and the accuracy in identifying the direction in which the alarm sound is generated can be improved.

  In addition, the warning sound generation direction notification system 1 can be suitably applied to the vehicle 3 which is a truck having a relatively large vehicle body. That is, if the housing 10 is fixed to the side surface 4 of the driver's seat portion 3A, the mounting operation is completed, so that mounting is easy. In addition, since the housing 10 is fixed to the side surface 4 of the driver seat 3A, which has a relatively uniform shape, rather than the loading platform 3B having a shape that varies greatly depending on the vehicle type, the problem of the mounting position is less likely to occur. Furthermore, even when the present invention is applied to the vehicle 3 which is a truck having a relatively large vehicle body, the accuracy of identifying the direction of occurrence is less dependent on the vehicle body shape.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments. The present invention can be modified without departing from the scope described in the claims or applied to other embodiments. May be.

  In the above embodiment, an example in which the notification unit 50 (the first notification unit 51 and the second notification unit 52) is configured by an LED has been described. However, the notification unit 50 can notify the driver of the direction in which the alarm sound is generated. If it is good, it is not limited to this. For example, an indicator displayed on the meter 5 or an LED disposed on the instrument panel may be used. Moreover, it is not restricted to visual alerting | reporting, You may alert | report alert | reporting instead of this or in addition to this.

  In the above-described embodiment, an example in which only the direction in which the alarm sound is generated has been described, but in addition to this, for example, by calculating the relative speed between the vehicle 3 and the emergency vehicle by using the Doppler effect or the like, is approaching? It is good also as a structure which alert | reports whether it is separated. Alternatively, the relative speed from the vehicle 3 to the emergency vehicle may be calculated based on a difference in volume level as a time series of sounds detected by the first microphone 20 and the second microphone 30.

  In the above-described embodiment, an example in which the housing 10 is fixed to the frame portion 4B of the side surface 4 on the oncoming vehicle side of the driver's seat portion 3A has been described, but the mounting position is not limited thereto. For example, it may be fixed to any one of the upper surface, the lower surface, the left surface, and the right surface of the driver's seat portion 3A, or may be fixed to the door portion 4A and the cargo bed portion 3B.

DESCRIPTION OF SYMBOLS 1 ... Warning sound generation direction notification system, 3 ... Vehicle, 3A ... Driver's seat part, 3B ... Loading platform part, 4 ... Side surface (vehicle body outer surface), 4A ... Door part, 4B ... Frame part, 5 ... Meter, 10 ... Housing , 20 ... first microphone, 30 ... second microphone, 40 ... circuit board (identification part), 50 ... notification part, 51 ... first notification part, 52 ... second notification part, 61 ... bandpass Filter processing 62... High-pass filter processing 63 63 Invert amplification processing 64 64 Low pass filter processing 65 Inversion amplification processing 66 Rectification processing 67 Smoothing processing 68 Differential amplification processing 69 Inversion processing 70: Comparator processing.

Claims (2)

A housing fixed to the outer surface of the vehicle ;
First and second microphones having directivity accommodated in the housing in proximity to each other;
An identification unit for identifying the direction in which the warning sound of the emergency vehicle is generated based on the sound detected by the first and second microphones;
A notification unit for notifying a driver of the direction of generation of the warning sound identified by the identification unit,
No microphones other than the first and second microphones are provided,
The vehicle is a truck having a driver's seat and a loading platform,
The casing is fixed to a side surface of the driver seat on the side of the oncoming vehicle,
The first microphone is arranged with the directivity in front of the vehicle, and the second microphone is arranged with the directivity in the rear of the vehicle,
The identification unit is configured to identify whether a direction in which the alarm sound is generated is forward or backward based on a difference in sound volume level detected by the first and second microphones. Sound generation direction notification system.   The discriminating unit discriminates a difference in volume level between the sounds detected by the first and second microphones after performing a band-pass filter process of a pass band corresponding to the frequency band of the alarm sound. The alarm sound generation direction notification system according to claim 1, wherein:

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