JP2005115813A - Vehicle detecting method, vehicle detecting device and parking lot management system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more appropriately detect vehicles in a parking lot in a parking lot management system using a microphone. <P>SOLUTION: This vehicle detecting method for detecting the vehicles in the parking lot comprises the step of: detecting vehicle sound near a parking frame by using a microphone array provided with at least two microphones apart from each other; specifying the direction of a sound source based on time difference when the vehicle sound reaches to each microphone; and detecting that the vehicle sound disappears when it is determined that the vehicle exists within the parking frame to determine that the parking is completed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vehicle detection method and the like, and more particularly, to a vehicle detection method and a vehicle detection device used in a parking lot, and a parking lot management system using them.

  Conventionally, there are various vehicle detection methods and vehicle detection devices used in parking lots. Some of them detect vehicle sound with a microphone and detect the presence and position of the vehicle based on an acoustic signal generated from the vehicle sound. An example of a parking lot management system using a microphone is disclosed in “Parking lot management device by acoustic monitoring” of Japanese Patent Laid-Open No. 2002-260186. The conventional parking lot management system disclosed therein installs a plurality of microphones at intervals so that installation coordinates can be understood, and collects engine sounds using at least three or more microphones optimal for monitoring. Therefore, sound monitoring is performed (for example, refer to Patent Document 1).

JP 2002-260186 A

  However, the above conventional example has the following problems. That is, in the above conventional example, the number of microphones installed is smaller than the number of parking frames. For this reason, each microphone simultaneously detects an unspecified number of vehicle sounds present in the surroundings, resulting in inconvenience that it is necessary to identify each vehicle and determine the position of each vehicle. Further, in order to determine the position of the vehicle, it is necessary to determine the installation coordinates of each microphone in advance and to accurately install the microphones, so that there is a problem that installation and relocation are complicated. Furthermore, since a wide range of sounds is detected by a small number of microphones, there is a problem that it is easily affected by surrounding environmental noise other than the vehicle sound and it is difficult to determine the vehicle position.

In order to solve the above problems, in the present invention, a vehicle sound near each parking frame is detected by a microphone array having at least two microphones spaced apart from each other, and based on a time difference when the vehicle sound reaches each microphone. The sound source direction is specified, and it is determined whether or not the vehicle is in the parking frame based on the information of the specified sound source direction, and the vehicle sound disappears when it is determined that the vehicle is in the parking frame. This is a method of detecting that the parking has been completed. For this reason, the vehicle sound emitted from one sound source reaches each microphone with a predetermined time difference. This time difference corresponds to the difference in distance from the sound source to each microphone, and the direction of the sound source can be specified based on the difference in distance. In addition, since the microphone array is installed for each parking frame or for every two adjacent parking frames, a vehicle having one or two parking frames can be detected by each microphone array.
In the present invention, a cross-correlation calculation is performed in order to obtain a time difference between arrival times of vehicle sounds. The cross-correlation calculation is a technique in which one of the waveforms to be compared is shifted and the time difference is determined by the shift amount when the waveform best matches the other waveform. For this reason, the time difference can be calculated more accurately, and the accuracy of vehicle detection is improved.

According to the present invention, the vehicle parking position and the completion of parking are determined based on the vehicle sound, so that the vehicle stopping means can be operated in a state where the vehicle is reliably stopped, and the vehicle stopping means erroneously damages the vehicle. Is resolved. In addition, an easily installable microphone array can be installed in the parking frame, or integrated with the vehicle stop means and the vehicle stop block, and there is no need to provide a separate space for installing the microphone in the parking lot. A frame can be secured. Moreover, installation and relocation can be performed easily.
In addition, since the vehicle detection for each parking frame is performed by a microphone array installed in each parking frame, it is possible to manage the entry / exit of the vehicle by simply detecting the vehicle direction without detecting the position coordinates of the vehicle. It is not necessary to know the installation coordinates of the array, and the installation work is easy.

BEST MODE FOR CARRYING OUT THE INVENTION

First, a vehicle detection apparatus according to an embodiment of the present invention will be described. FIG. 1 is a diagram showing a microphone array 1 used in a vehicle detection device. 1A is a front view of the microphone array 1, and FIG. 1B is a plan view. The microphone array 1 includes a predetermined base member 13 having a cross shape, and a total of five microphones 11 installed at each end and center of the base member 13.
In addition, a predetermined wiring 14 connected to each microphone 11 is provided in the base member 13, so that sound detected by each microphone 11 can be transmitted to the outside through the wiring 14 as an acoustic signal. ing. In the microphone array 1 of FIG. 1, the microphone 11 is installed on the cross-shaped base member 13, but the present invention is not limited to such a configuration, and both end portions of a simple rod-shaped base member are used. In the case where two microphones are respectively installed, or in addition to the microphones at both ends of the rod-like base member, a microphone array may be provided in which one microphone is provided at the center and a total of three microphones are installed.

  Next, based on FIG. 2, the principle of the vehicle detection method using the vehicle detection apparatus of this invention is demonstrated. FIG. 2 shows a front view of the microphone array 1 installed on the road surface of the parking frame. And this figure is a figure which shows the state in which the predetermined vehicle sound has reached each microphone 11a, 11b from diagonally right above. In this case, vehicle sound generated from the vehicle at a certain point arrives at the leftmost microphone 11a later than the rightmost microphone 11b. This is because the distance from the sound source to the leftmost microphone 11a is longer than the distance to the rightmost microphone 11b.

The sound source direction can be obtained based on such characteristics. Specifically, a predetermined vehicle sound is detected, and the time when the sound is detected by the leftmost microphone 11a and the time when the sound is detected by the rightmost microphone 11b are stored. And the time difference when a vehicle sound arrives at both the microphones 11a and 11b from these times is calculated. By multiplying this time difference by the speed of sound, a difference P in distance from the sound source can be calculated. Then, as shown in FIG. 2, since the relationship of cos α = P / L can be derived from the obtained distance difference P and the distance L between the microphones, the angle α formed between the sound source direction and the straight line connecting the two microphones is obtained. The sound source direction can be specified by obtaining.
For example, it is assumed that the time difference when the vehicle sound reaches each microphone is about 1.5 msec. The sound speed is assumed to be about 340 m / sec. As a result, the distance difference P corresponding to the distance that the sound travels in 1.5 msec is P = 340 × 0.0015 sec = about 51 cm. Further, the distance L between the microphones in this embodiment is set to 59 cm. Therefore, P / L = 51/59 = about 0.87, and α = arccos0.87 = about 30 °. As a result, it can be seen that the sound source exists in a direction about 30 ° obliquely upward from the microphone array.

  However, simply using the time difference between vehicle sounds at a certain point in time cannot improve the detection accuracy. This is because various environmental noises reach the parking lot in addition to the vehicle sound. For this reason, in order to specify the sound source direction of the vehicle, a cross-correlation calculation may be used as a method for obtaining the time difference of the vehicle sound. The cross-correlation calculation is a function of the shift amount when only one waveform of the two signal data is delayed, and is defined by the following (Formula 1).

この数式１は、２つの波形の類似度を量的に表すものであり、２つの信号データの重なり面積がピークの時（類似度が高い時）のずらし量を調べることで、２つの波形の位相差（時間差）を求めることができる。そして、時間差が求まったら上記と同様に、音源から各マイクロフォンへの距離の差Ｐを求める。このように、相互相関演算を用いることにより、相互に対応する車両音の時間差を正確に求めることができ、より精度の高い音源方向の特定が可能となり、この結果車両検出の精度も向上することとなる。

This mathematical expression 1 quantitatively represents the similarity between two waveforms. By examining the shift amount when the overlapping area of two signal data is at a peak (when the similarity is high), A phase difference (time difference) can be obtained. When the time difference is obtained, the difference P in distance from the sound source to each microphone is obtained in the same manner as described above. Thus, by using the cross-correlation calculation, it is possible to accurately determine the time difference between the vehicle sounds corresponding to each other, and it is possible to specify the direction of the sound source with higher accuracy, thereby improving the accuracy of vehicle detection. It becomes.

Although the above description is a method of performing vehicle detection using two microphones, the present invention is not limited to this. That is, the direction of the sound source can be specified with higher accuracy by specifying the direction of the sound source using the vehicle sound detected by the microphone 11c located in the center of FIG.
The above description of the principle describes a vehicle detection method using microphones arranged in one direction (for example, the vehicle approach direction). However, as described above, since the microphone array 1 is provided with the microphone rows in the directions orthogonal to each other, the microphone row in the other direction (for example, the direction orthogonal to the vehicle approach direction) is also used in the same manner. The direction of the sound source can be specified. Therefore, by combining the detection results of the microphone rows orthogonal to each other, it is possible to detect in which direction on the road surface the sound source is present with respect to the microphone array 1. This makes it possible to determine whether the vehicle is in the parking frame.

FIG. 3 is a schematic view showing a vehicle detection apparatus 1A using the microphone array 1. As shown in FIG. In addition to the microphone array 1, the vehicle detection device 1 </ b> A is provided with an A / D converter 15 and predetermined control means 17. The A / D converter 15 has a function of converting an analog signal from each microphone array 1 into a digital signal. Here, a plurality of microphone arrays 1 are shown (four in the figure) because a microphone array is installed for each parking frame or one microphone array is installed for two parking frames. This is because a large number of microphone arrays are used in the entire parking lot.
The control means 17 receives an acoustic signal converted from a vehicle sound into a digital signal by the A / D converter 15 and performs the above-described cross-correlation calculation and various controls described later. The control means 17 is an information processing apparatus such as a computer, and includes predetermined information input means, information output means, information display means, information storage means, and the like.

FIG. 4 is a schematic explanatory diagram when the vehicle detection device 1A of the present invention is applied to an actual parking lot. As shown in this figure, the microphone array 1 is fixed to a substantially central portion of the parking frame 25 by anchor bolts (not shown) or the like. For this reason, when the vehicle is parked, the microphone array 1 is positioned directly below the vehicle. Further, as shown in the figure, the cross-shaped microphone array 1 has one microphone row (three microphones) arranged in a first direction parallel to the vehicle approach direction to the parking frame 25 and the vehicle approach direction. The other microphone row is arranged in a second direction perpendicular to the other. This is to detect both the direction of the sound source relative to the vehicle approach direction and the direction of the sound source relative to the direction perpendicular to the vehicle approach direction, as will be described later. In addition, when using a rod-shaped microphone array, you may install in parallel with the approach direction of a vehicle, or may install in the direction orthogonal to this. Further, the rod-shaped microphone arrays may be installed at different positions at right angles to each other.
The parking frame 25 is provided with predetermined vehicle stopping means 23. The vehicle stopping means 23 is raised after the vehicle enters the parking frame 25 and is lowered when the parking fee is properly settled, and is intended to prevent the vehicle from being illegally issued. The vehicle stop means 23 is controlled by the control means 17 described above. The vehicle stop means of this embodiment is a flap type, and the operation will be described later. A predetermined vehicle stop block 21 is installed in the parking frame 25. The vehicle stop block 21 is for preventing a vehicle entering for parking from deviating from the parking frame 25. When the vehicle enters, the vehicle tire comes into contact with the stop block so that no further entry is possible. Further, a predetermined parking settlement machine 19 is provided in the vicinity of the parking frame 25. This parking settlement machine 19 is for the user to settle the parking fee, and accommodates the control means 17 therein. For this reason, the parking payment machine, the microphone array 1 and the vehicle stop means 23 are connected to each other by wiring (dotted line in the figure).
In the case of an indoor parking lot, the waterproofing of the microphone is not a problem, but when a microphone array is installed in an outdoor parking lot, it is desirable to use a waterproof microphone.

Next, based on FIG. 5, the structure of the parking lot management system 1B of this invention using the said vehicle detection apparatus 1A is demonstrated. The vehicle detection apparatus 1A accommodates the control means 17 described above, and a sound source direction specifying means 26 is further provided in the control means 17. This sound source direction specifying means 26 specifies the direction in which the vehicle exists based on the acoustic signal converted from the vehicle sound by the microphone array 1, and calculates the direction α of the vehicle according to the above formula 1. Further, the vehicle detection apparatus 1A includes the parking settlement machine 19 as described above. The parking settlement machine 19 is provided with a control means 17, and a vehicle stop means 23 is connected to the control means 17 and a predetermined warning means. 27, recording means 29 and reporting means 31 are connected.
The warning means 27 has a function of calling attention to surrounding vehicles and users when the vehicle leaves the parking frame. In addition, it also has a function of detecting a fraudulent act in a parking lot and giving a warning to a person who commits the fraud. Moreover, the recording means 29 records the sound which generate | occur | produces in a parking lot, the voice which an unauthorized intruder utters, etc. Furthermore, the reporting means 31 reports this to the outside when fraud or abnormality is detected in the parking lot.

  Next, a vehicle detection method using the vehicle detection device 1A according to the present invention will be described in detail with reference to FIG. FIG. 6 is a flowchart when the vehicle enters the parking lot and parks. The vehicle detection device 1A always detects ambient sounds using the microphone array 1 (step S1). And if the microphone array 1 detects a sound, the acoustic signal of the vehicle sound detected by each microphone 11 will be transmitted to the control means 17 in the parking checker 19. Based on this acoustic signal, the sound source direction specifying means 26 performs the above-described cross-correlation calculation to calculate the phase difference of the acoustic signal between the microphones, and specifies the direction of the sound source based on this phase difference (step S2). ).

In the control means 17, it is determined whether or not the sound source is present in the direction corresponding to the parking frame 25 based on the obtained sound source direction information (step S3). Here, when it is determined that the sound source does not exist in the parking frame 25, the direction of the sound source is specified again based on the vehicle sound detected by the microphone array 1 (steps S1 and S2). Then, this operation is repeated until it is determined that the sound source is present in the parking frame 25. On the other hand, if it is determined that the sound source is present in the direction corresponding to the parking frame 25, it is then determined whether or not the vehicle sound from the sound source direction has disappeared (step S4). If it is determined that the vehicle sound has disappeared, it is determined that the vehicle is parked. This is because there is no detectable vehicle sound when the engine or the like is stopped for parking. The above is the procedure of the vehicle detection method at the time of parking. As vehicle sounds, cell motor operation sounds, door opening / closing sounds, side brake operation sounds, etc. can be detected by specifying the sound source direction based on the sound source position and sound characteristics. is there.
When it is determined that the operation state can be estimated and the parking of the vehicle has been completed, the control unit 17 activates the vehicle stopping unit 23 so that the vehicle cannot be delivered, and charging by the parking settlement machine 19 is started. As shown in FIG. 4, the vehicle stop means 23 used in the present embodiment is a flap-type vehicle stop means 23, and the flap is raised after a predetermined time has elapsed since it was determined that parking was completed.

  Next, based on FIG. 7, the case where a vehicle leaves is demonstrated. The vehicle detection device 1A detects the vehicle sound with the microphone 11 when the vehicle engine is started for delivery (step S11). The acoustic signal obtained based on the vehicle sound is transmitted to the sound source direction specifying means 26 of the control means 17. The sound source direction specifying means 26 specifies the direction of the sound source by cross-correlation calculation based on the transmitted acoustic signal (step S12). Further, whether or not the sound source direction is a direction corresponding to the parking frame 25 based on the obtained sound source direction information, or whether the microphone array 1 has detected an abnormal sound when getting over the vehicle stopping means 23 Is determined (step S13). If it is determined that any of the above conditions is satisfied, it is next determined whether or not the parking fee settlement by the parking settlement machine 19 is completed (step S14).

  If it is determined in the above process that the payment of the parking fee has been completed, the car stop means 23 is lowered because it is normal delivery (step S15). On the other hand, if it is determined that the settlement has not been completed, it is recognized as an unauthorized shipment (step S16), and the locus of the sound source direction and the time when the vehicle departs from the parking frame 25, or when the vehicle stopping means 23 is overtaken. The abnormal sound and its time are recorded in the recording means 29 (step S17). In addition, since the abnormal sound may be a mischief or a theft of the parked vehicle, the warning means 27 gives a warning to the intruder performing such an action. Moreover, the recording means 29 records the abnormal sound for the parked vehicle and the voice uttered by the intruder. Then, the reporting means 31 reports to a user or a parking lot manager who has registered a contact information such as a mobile phone in advance that the parked vehicle is mischievous or stolen. In addition, when recognizing an unauthorized shipment, the time of entry / exit and the settlement time are recorded in the recording means, and it is determined whether or not it is an unauthorized shipment by comparing the settlement time to the parking settlement machine 19 and the departure time. Is also possible. As the abnormal sound, it is possible to estimate the occurrence of abnormality based on the position and the characteristics of the sound such as the breaking sound of the glass and the sound of opening the lock part.

8 and 9 show a method of installing a microphone array different from the case of FIG. FIG. 8 shows a vehicle stop block 21 for preventing the vehicle from accidentally deviating from the parking frame, and shows a case where the microphone array 1 is embedded in the vehicle stop block 21. However, in addition to being embedded in the car stop block 21, it is also possible to fix the car stop block 21 with a fixture such as an anchor bolt (not shown). As described above, when the microphone array 1 is installed in the vehicle stop block 21, only the vehicle sound of the corresponding parking frame 25 can be detected. Note that the microphone array may be installed not in the vehicle stop block 21 but in the vehicle stop means 23.
On the other hand, FIG. 9 shows an installation example of the microphone array 1 when two parking frames 25a and 25b are adjacent to each other. In such a case, one microphone array 1 is embedded in the boundary between the two parking frames 25a and 25b or fixed by anchor bolts or the like, so that the two parking frames 25a and 25b on both sides of the installed microphone array 1 are used. Only the vehicle sound can be detected.

  The present invention is not limited to the above embodiment, and other modifications are possible. For example, an acoustic signal transmitted from the microphone array 1 is passed through a low-pass filter (in some cases, a high-pass filter). Thus, it is conceivable to select and extract a signal having a predetermined frequency. This is because various sounds other than the vehicle sound reach the parking lot, but since the frequency band of the vehicle sound is known in advance, environmental noise other than the vehicle sound can be removed, and the vehicle direction detection accuracy is improved. Because it can.

Further, when the microphone array 1 is installed at a position corresponding to the lower side of the vehicle, it may be affected by sound from the muffler. When engine sound is used as vehicle sound, low-frequency sound from the muffler may reduce detection accuracy. In order to prevent this reduction in detection accuracy, the vehicle direction detection accuracy can be improved by cutting low frequency components included in the muffler sound.
Further, in an unmanned parking lot, a front stopper is provided at the end of the parking frame in order to prevent unauthorized removal of the vehicle, and the front stopper is raised during parking. In this case, since the vehicle sound is detected by the microphone in the present invention, if the sound is detected when the front stopper comes into contact with the vehicle, the front stopper is lowered so that the front stopper greatly damages the vehicle. You may make it prevent. In this case, the frequency band of the sound generated when the front stopper comes into contact with the vehicle is examined in advance, and compared with the frequency component of the detected sound, it can be determined that the front stopper is in contact.

The present invention can be applied to an application for detecting a vehicle with high accuracy in an unmanned parking lot.

It is a figure which shows the microphone array used with the vehicle detection apparatus of this invention, FIG. 1 (A) shows a front view, FIG.1 (B) shows a top view. FIG. 2 is a diagram for explaining the principle of sound source direction identification using the microphone array disclosed in FIG. It is a schematic perspective view which shows the vehicle detection apparatus of this invention. It is a schematic perspective view which shows the parking lot using the vehicle detection apparatus of this invention. It is a block diagram which shows the parking lot management system of this invention. It is a part of vehicle detection method of this invention, Comprising: It is a flowchart which shows the procedure at the time of warehousing. It is a part of vehicle detection method of this invention, Comprising: It is a flowchart which shows the procedure at the time of leaving. It is a perspective view which shows the modification of this invention, and shows the state which embedded the microphone array in the vehicle stop block. It is a perspective view which shows the other modification of this invention, and shows the state which installed the microphone array in the boundary part of an adjacent parking frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microphone array 1A Vehicle detection apparatus 1B Parking lot management system 11, 11a, 11b, 11c Microphone 13 Base member 17 Control means 18 Sound source direction identification means 19 Parking settlement machine 21 Car stop block 23 Car stop means 25 Parking frame 27 Warning means 29 Recording means 31 Reporting means
L Distance between microphones P Difference in distance

Claims (16)

A vehicle detection method for detecting a vehicle in a parking lot,
Detecting a vehicle sound near each parking frame with a microphone array having at least two microphones spaced apart from each other;
Identifying a sound source direction based on a time difference when the vehicle sound reaches each microphone;
Determining whether a vehicle is present in the parking frame based on the information of the identified sound source direction;
When it is determined that the vehicle is present in the parking frame, the step of detecting that the vehicle sound has disappeared and determining that parking is completed; and
The vehicle detection method characterized by including.   The vehicle detection method according to claim 1, wherein the time difference between the vehicle sounds is obtained by a cross-correlation calculation. In the step of identifying the sound source direction, vehicle sound is detected by the microphone row arranged along a first direction parallel to the vehicle approach direction to the parking frame, and at right angles to the first direction. Vehicle sound is detected by the microphone array arranged along the second direction;
The vehicle detection method according to claim 1 or 2, wherein, in the step of specifying the sound source direction, a sound source direction in the first and second directions is specified. Installing the microphone array at the boundary between the first and second parking frames adjacent to each other;
4. The method according to claim 3, wherein whether the vehicle is present in the first or second parking frame is determined based on the sound source direction obtained in the step of specifying the sound source direction. 5. Vehicle detection method.   The vehicle sound of a predetermined frequency is selectively extracted from the vehicle sounds detected by the microphone array, and the sound source direction is specified based on the vehicle sound of the predetermined frequency. The vehicle detection method according to any one of the above. A vehicle detection device for detecting a vehicle in a parking lot,
A microphone array comprising at least two microphones spaced apart from each other and disposed in the vicinity of each parking frame to detect vehicle sound;
Sound source direction specifying means for specifying a sound source direction based on a time difference when the vehicle sound reaches each microphone;
Based on the information on the specified sound source direction, it is determined whether or not the vehicle is present in the parking frame, and when the vehicle is determined to be present in the parking frame, it is detected that the vehicle sound has disappeared. And control means for judging that parking is completed,
A vehicle detection device comprising:   The vehicle detection device according to claim 6, wherein the sound source direction specifying unit obtains a time difference between the vehicle sounds by cross-correlation calculation. The microphone array is arranged along a first microphone row arranged along a first direction parallel to a vehicle approach direction to the parking frame, and a second direction perpendicular to the first direction. A second microphone row,
The vehicle detection device according to claim 6 or 7, wherein the sound source direction specifying means specifies a sound source direction in the first and second directions. Installing the microphone array at the boundary between the first and second parking frames adjacent to each other;
The said sound source direction identification means judges whether the said vehicle exists in the said 1st or 2nd parking frame based on the information of the acquired sound source direction. Vehicle detection device.   The vehicle detection device according to claim 8 or 9, wherein the microphone array is formed in a cross shape by the first microphone row and the second microphone row.   The vehicle detection device according to claim 6, wherein the microphone array is installed in a predetermined vehicle stop block provided in the parking frame. A parking lot management system that detects vehicles in a parking lot and manages the parking lot,
A microphone array comprising at least two microphones spaced apart from each other and disposed in the vicinity of each parking frame to detect vehicle sound;
Sound source direction specifying means for specifying a sound source direction based on a time difference when the vehicle sound reaches each microphone;
Based on the information on the specified sound source direction, it is determined whether or not the vehicle is present in the parking frame, and when the vehicle is determined to be present in the parking frame, it is detected that the vehicle sound has disappeared. And control means for determining that parking is completed,
Each of the microphone arrays includes a first microphone row arranged along a first direction parallel to a direction in which the vehicle enters the parking frame, and a second direction perpendicular to the first direction. A second microphone array arranged,
The sound source direction specifying means specifies a sound source direction in the first and second directions;
The control means locks the vehicle by the vehicle stopping means installed in each parking frame when it is determined that parking is completed, starts charging, and releases the lock of the vehicle stopping means when it is determined that payment is completed. Parking management system to do.   13. The parking lot management system according to claim 12, wherein the sound source direction specifying means obtains a time difference between the vehicle sounds by cross-correlation calculation.   14. The parking lot management system according to claim 12, further comprising warning means for issuing a warning for starting the vehicle around the parking frame when the vehicle sound is detected again after the completion of parking.   When the sound detected from the microphone includes a sound that deviates from a preset frequency band, it is provided with storage means for storing the detected sound determined to be an abnormal situation of the vehicle. The parking lot management system according to any one of claims 12 to 14.   The parking lot management system according to any one of claims 12 to 15, further comprising reporting means for reporting an abnormality of the vehicle to the outside when an abnormal situation of the vehicle is detected.

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