JP2023119923A - Vehicle occupant detection device, vehicle occupant detection method, and vehicle occupant detection program - Google Patents

Abstract

To provide a vehicle occupant detection device which can detect someone left unattended in the vehicle with higher accuracy.SOLUTION: A vehicle occupant detection device 10 comprises: a first acquisition unit 11 that acquires a sensor signal of a radio wave sensor 20 which is mounted on a vehicle U and detects an object in the vehicle U; a second acquisition unit 12 that acquires a sensor signal of a vibration sensor 30 which is mounted on the vehicle U and detects the vibration of the vehicle U; an occupant determination unit 14 that analyzes the presence state of the object in the vehicle U at the present time on the basis of the sensor signal of the radio wave sensor 20 and determines the presence of an occupant in the vehicle U from the analysis result; a detection timing control unit 15 that analyzes a vibration state of the vehicle U at the present time on the basis of the sensor signal of the vibration sensor 30, allows the determination by the occupant determination unit 14 to be carried out when the vehicle U is not vibrating, and does not allow the determination by the occupant determination unit 14 to be carried out when the vehicle U is vibrating; and a notification unit 16 that notifies the determination result of the occupant determination unit 14 to the outside of the vehicle U.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a vehicle occupant detection device, a vehicle occupant detection method, and a vehicle occupant detection program.

Conventionally, there have been cases where a parent leaves a child in the vehicle and leaves the vehicle outside, forgetting that the child is still inside the vehicle (left for a long time). As a result, serious health hazards such as heatstroke have occurred.

Therefore, an abandoned-abandonment detection system for detecting that a child is left behind in a vehicle and issuing an alarm has begun to be installed in the vehicle. In such a system, the presence or absence of a living body such as a child in the vehicle is detected using the parent's movement to leave the vehicle as a trigger. An alarm is issued to the outside of the vehicle, or a notification is sent to a smartphone or the like to the guardian.

For example, Patent Literature 1 describes an occupant state detection system that issues an alarm when a person is left in the vehicle. Specifically, the occupant state detection system detects whether or not a person has left the front seat (driver's seat or front passenger seat), and when it detects that a person has left the seat, If the object in the detection target area is determined to be a person, an alarm is output.

JP 2020-101415 A

By the way, in recent years, in this type of abandoned vehicle detection system, the use of radio wave sensors has been studied as a means for detecting the presence of a person inside the vehicle (see, for example, Patent Document 1). The radio wave sensor, for example, is attached to the ceiling of the vehicle interior, transmits radio waves (transmission waves) to the detection target area in the vehicle interior, receives radio waves (reflected waves) reflected by objects in the detection target area, This is a sensor that detects an object existing in the passenger compartment.

In this type of abandoned child detection system, while the vehicle is stopped (that is, while the vehicle is left unattended), the state of the child being left behind in the vehicle (hereinafter abbreviated as "inside the vehicle") is continuously detected. is detectable. In this regard, unlike the occupant detection system using a weight sensor or a pressure sensor, the abandoned object detection system using radio wave sensors directly detects the interaction between people and objects other than people (such as luggage) based on the movement of people. Since the identification is performed, it is useful in that even while the vehicle is left unattended, it can be detected easily and with high accuracy.

An abandoned vehicle detection system using a radio wave sensor normally determines whether or not the sensor signal of the radio wave sensor contains a human breathing frequency component (for example, about 0.16 Hz to 1.00 Hz). Detect the presence of people. This detection method utilizes the fact that the body of a person (e.g., a child) normally oscillates at the respiratory frequency. to distinguish objects in the vehicle as human or non-human objects.

FIG. 1 is a diagram for explaining detection processing relating to the presence or absence of a passenger in an abandoned vehicle detection system using a radio wave sensor. FIG. 1A is a diagram showing an example of a heat map obtained from a sensor signal of a radio wave sensor when there is no person in the vehicle. FIG. 1B is a diagram showing an example of a heat map obtained from a sensor signal of a radio wave sensor when a person is present inside the vehicle. FIG. 1C shows the sensor of the radio wave sensor when there is no person in the vehicle and the vehicle is vibrating slightly (more precisely, when the object in the vehicle is vibrating due to the vehicle's slight vibration). FIG. 4 is a diagram showing an example of a heat map obtained from a signal; The heat maps of FIGS. 1A to 1C are all generated based on sensor signals of radio wave sensors acquired while the vehicle is stopped.

From the sensor signal of the radio wave sensor, it is possible to identify the distance to the object detected by the radio wave sensor and the frequency of the movement of the detected object. As an example of a method for extracting the respiratory frequency component from the sensor signal of the radio wave sensor, there is a method using FFT (Fast Fourier Transform). A "heat map" of frequency (i.e., the frequency component of the sensor signal) x distance (i.e., the distance from the radio wave sensor to the detected object) x signal strength (brightness of each region of the heat map), as in Figure 1C. can be converted to

In the process of detecting the presence or absence of a passenger, for example, from this heat map, a person's breathing frequency component (eg, 0.5 m to 1.00 m) observed within an appropriate distance range (eg, about 0.5 m to 1.00 m) is detected. 16 Hz to 1.00 Hz) (R1 region in FIGS. 1A to 1C) is extracted to determine presence/absence. As can be seen from FIGS. 1A and 1B, when there is a person in the vehicle (FIG. 1B), compared to when there is no person in the vehicle (FIG. 1A), the signal strength in the R1 region is strongly observed.

However, the inventors of the present application have been researching and developing an abandoned vehicle detection system using such a radio wave sensor. sound, an external force from a person who touches the vehicle, or an earthquake, etc.), and the minute vibration of the vehicle causes objects in the vehicle to breathe at a breathing frequency (for example, 0.16 Hz to 1.5 Hz). 00 Hz). Objects in the vehicle that are likely to shake due to minute vibrations of the vehicle include, for example, liquids in PET bottles, luggage suspended in the cabin, shopping bags containing products, and objects containing luggage. A basket etc. are mentioned.

FIG. 1C shows a mode in which a strong signal intensity is observed in the R1 region in the heat map, similar to the case where a person is present in the vehicle interior (FIG. 1B) due to the shaking of objects inside the vehicle. . As a result, even if the vehicle is unmanned, it may be erroneously detected as being occupied (that is, the vehicle has been left behind), and an alarm may be output unnecessarily.

The present disclosure has been made in view of the above problems, and an object thereof is to provide a vehicle occupant detection device, a vehicle occupant detection method, and a vehicle occupant detection program capable of more accurately detecting an abandoned person in a vehicle.

The main disclosure that solves the above-mentioned problems is
a first acquisition unit that is mounted on a vehicle and acquires a sensor signal from a radio wave sensor that detects an object in the vehicle;
a second acquisition unit that is mounted on the vehicle and acquires a sensor signal of a vibration sensor that detects vibration of the vehicle;
an occupant determination unit that analyzes the existence state of an object in the vehicle at the current time based on the sensor signal of the radio wave sensor, and determines the presence or absence of an occupant in the vehicle from the analysis result;
Based on the sensor signal of the vibration sensor, the current vibration state of the vehicle is analyzed, and when the vehicle is not vibrating, execution of the determination by the occupant determination unit is permitted, and the vehicle is vibrating. a detection timing control unit that sometimes disallows execution of the determination by the occupant determination unit;
a notification unit that notifies the outside of the vehicle of the determination result of the occupant determination unit;
A vehicle occupant detection device comprising:

Also, in other aspects,
A first process of acquiring a sensor signal of a radio wave sensor mounted on a vehicle and detecting an object in the vehicle;
a second process of acquiring a sensor signal of a vibration sensor mounted on the vehicle and detecting vibration of the vehicle;
a third process of analyzing the existence state of an object in the vehicle at the current time based on the sensor signal of the radio wave sensor, and determining the presence or absence of an occupant in the vehicle from the analysis result;
Based on the sensor signal of the vibration sensor, the current vibration state of the vehicle is analyzed, and when the vehicle is not vibrating, execution of the determination in the third process is permitted, and the vehicle is vibrating. a fourth process that sometimes disallows execution of the determination in the third process;
a fifth process for informing the outside of the vehicle of the determination result of the third process;
A vehicle occupant detection method comprising:

Also, in other aspects,
to the computer,
A first process of acquiring a sensor signal of a radio wave sensor mounted on a vehicle and detecting an object in the vehicle;
a second process of acquiring a sensor signal of a vibration sensor mounted on the vehicle and detecting vibration of the vehicle;
a third process of analyzing the existence state of an object in the vehicle at the current time based on the sensor signal of the radio wave sensor, and determining the presence or absence of an occupant in the vehicle from the analysis result;
Based on the sensor signal of the vibration sensor, the current vibration state of the vehicle is analyzed, and when the vehicle is not vibrating, execution of the determination in the third process is permitted, and the vehicle is vibrating. a fourth process that sometimes disallows execution of the determination in the third process;
a fifth process for informing the outside of the vehicle of the determination result of the third process;
is a vehicle occupant detection program that executes

According to the vehicle occupant detection device according to the present disclosure, it is possible to detect a person left behind in a vehicle with higher accuracy.

A diagram for explaining the detection processing related to the presence or absence of an occupant in an abandoned-abandonment detection system using a radio wave sensor. 1 is a diagram showing an example of the configuration of an abandoned object detection system according to an embodiment of the present invention; FIG. 1 is a diagram showing an example configuration of a vehicle occupant detection device according to an embodiment of the present invention; FIG. 1 is a flow chart showing an example of the operation of a vehicle occupant detection device according to an embodiment of the present invention; Flowchart showing an example of the operation of the vehicle occupant detection device according to the modification of the present invention FIG. 11 is a diagram showing a notification mode during exception processing of the vehicle occupant detection device according to the modification of the present invention;

Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functions are denoted by the same reference numerals, thereby omitting redundant description.

An abandoned object detection system (hereinafter referred to as "an abandoned object detection system 1") according to an embodiment of the present invention will be described below.

FIG. 2 is a diagram showing an example of the configuration of the abandoned object detection system 1. As shown in FIG.

The abandoned-abandonment detection system 1 is provided in a vehicle U. For example, when a parent and a child are riding in the vehicle U, the parent leaves the child inside the vehicle U (specifically, inside the vehicle). This is used to prevent the child from going out of the vehicle and forgetting that the child exists in the vehicle and leaving the child in the vehicle. The vehicle U is, for example, a passenger car in which a plurality of passengers can ride.

The abandoned vehicle detection system 1 includes a vehicle occupant detection device 10 , a radio wave sensor 20 , a vibration sensor 30 , a vehicle state detection sensor 40 , a warning sound generator 51 , a warning light generator 52 and a wireless communication device 53 .

In the abandoned child detection system 1, the vehicle occupant detection device 10 determines whether or not a child is left behind in the vehicle U based on sensor signals from the radio wave sensor 20, the vibration sensor 30, and the vehicle state detection sensor 40, If it is determined that a child has been left behind, the alarm sound generating device 51, the warning light generating device 52, and the wireless communication device 53 are used to notify the outside of the vehicle U. .

The radio wave sensor 20 transmits radio waves (transmission waves) to a detection target area in the vehicle interior of the vehicle U, and receives radio waves (reflected waves) reflected by objects in the detection target area. This sensor obtains the distance from the radio wave sensor 20 to the object and the relative speed between the radio wave sensor 20 and the object from the time difference between the time it takes for the light to be reflected back and returned. That is, the radio wave sensor 20 outputs a sensor signal corresponding to the existing position of the object, the shape of the object, and the movement of the object. The radio wave sensor 20 is attached, for example, to the ceiling of the vehicle interior of the vehicle U, and detects an object present in the rear seat of the vehicle interior. Then, the radio wave sensor 20 transmits a sensor signal related to the object detected by itself to the vehicle occupant detection device 10 .

Although the sensor type of the radio wave sensor 20 is not particularly limited, the radio wave sensor 20 may be, for example, a Doppler sensor. The Doppler sensor transmits radio waves with a predetermined frequency toward the detection area as transmission waves, and receives the radio waves reflected by objects in the detection area as reception waves. output the sensor signal with the Doppler frequency. If the object that reflected the transmitted wave is moving or moving, the Doppler effect causes the frequency of the received wave to shift according to the speed of the object. Therefore, based on the sensor signal of the radio wave sensor 20, the velocity of the object can be obtained. For example, if the object is a person, by obtaining the speed of the object, it is possible to obtain not only the moving speed of the person, but also biometric information such as the movement of the person, such as the breathing movement of the person. The frequency band of radio waves used by the radio wave sensor 20 is, for example, a millimeter wave band or a giga wave band.

The vibration sensor 30 is installed inside the vehicle U (for example, the bottom plate of the vehicle U) and detects vibrations of the vehicle U. As shown in FIG. As described above, even when the vehicle U is stopped, external factors (for example, wind around the vehicle, sound outside the vehicle, external force from a person who touches the vehicle, or an earthquake, etc.) often cause slight vibrations. are doing. The vibration sensor 30 detects, for example, the vibration state of the vehicle U itself (that is, the body of the vehicle U) caused by such external factors, and thereby estimates the vibration state of all objects placed inside the vehicle U. do.

The sensor type of the vibration sensor 30 is not particularly limited as long as it can directly detect the vibration of the vehicle U. As the vibration sensor 30, for example, a triaxial acceleration sensor can be used. The three-axis acceleration sensor detects acceleration due to vibration on each of three axes fixed to the vibration sensor 30 and orthogonal to each other, and outputs a sensor signal representing the acceleration on each of the three axes.

The vehicle state detection sensor 40 detects a state related to whether the vehicle U is left or not by the user. The vehicle state detection sensor 40 is composed of, for example, a door lock sensor that detects locking/unlocking of the door locks of the vehicle U. By detecting that the vehicle U is locked from the outside, the vehicle U is put into an idle state ( It means that the user, who is the driver, leaves the vehicle U. The same applies hereinafter). The vehicle state detection sensor 40 may be configured by, for example, a seatbelt attachment/detachment sensor, a key-on/key-off sensor, or the like instead of the door lock sensor or together with the door lock sensor.

The warning sound generator 51, the warning light generator 52, and the wireless communication device 53 are notification means provided in the vehicle U, respectively. Here, the warning sound generating device 51 is, for example, a speaker capable of notifying the surroundings of the vehicle U of the occurrence of an abnormal situation by voice. Also, the warning light generator 52 is, for example, a headlamp and/or a tail lamp that can notify the surroundings of the vehicle U of the occurrence of an abnormal situation by lighting. The wireless communication device 53 is, for example, a communication device capable of notifying the terminal U1 of the user who is the administrator of the vehicle U of the occurrence of an abnormal situation by wireless communication.

The vehicle occupant detection device 10 is a signal processing device that detects the occurrence of an abandoned person in the vehicle based on sensor signals from the radio wave sensor 20, the vibration sensor 30, and the vehicle state detection sensor 40, respectively. Then, the vehicle occupant detection device 10 notifies the outside of the vehicle U using the warning sound generator 51, the warning light generator 52, and the wireless communication device 53 when the vehicle occupant is left behind. The vehicle occupant detection device 10 is housed in the dashboard of the vehicle U, for example.

The vehicle occupant detection device 10 includes various parts of the abandoned vehicle detection system 1 (here, the radio wave sensor 20, the vibration sensor 30, the vehicle state detection sensor 40, the warning sound generator 51, the warning light generator 52, and the wireless communication device 53). and controls the abandoned object detection system 1 as a whole. The vehicle occupant detection device 10 includes, for example, a CPU (Central Processing Unit) as a processor, a storage medium such as a ROM (Read Only Memory) storing a control program, a working memory such as a RAM (Random Access Memory), and a communication circuit. have In this case, the functions of the respective units described above are realized by the CPU executing the control program.

The vehicle occupant detection device 10, the radio wave sensor 20, the vibration sensor 30, the vehicle state detection sensor 40, the warning sound generator 51, the warning light generator 52, and the wireless communication device 53 are, for example, an in-vehicle network (eg, CAN communication protocol are connected to each other via a communication network conforming to the standard), and necessary data and control signals can be mutually transmitted and received.

The vehicle occupant detection device 10, the radio wave sensor 20, the vibration sensor 30, the vehicle state detection sensor 40, the warning sound generator 51, the warning light generator 52, and the wireless communication device 53 are mounted on the vehicle U, for example. It is configured to receive power supply from the on-vehicle battery and operate continuously even when the vehicle U is stopped (that is, while the key is off).

[Detailed Configuration of Vehicle Occupant Detection Device 10]
Here, the detailed configuration of the vehicle occupant detection device 10 will be described.

FIG. 3 is a diagram showing an example of the configuration of the vehicle occupant detection device 10. As shown in FIG.

The vehicle occupant detection device 10 has a first acquisition unit 11 , a second acquisition unit 12 , a third acquisition unit 13 , an occupant determination unit 14 , a detection timing control unit 15 and a notification unit 16 .

The first acquisition unit 11 acquires a sensor signal from the radio wave sensor 20 and sends the sensor signal to the occupant determination unit 14 .

The second acquisition unit 12 acquires a sensor signal from the vibration sensor 30 and sends the sensor signal to the detection timing control unit 15 .

The third acquisition unit 13 acquires a sensor signal from the vehicle state detection sensor 40 and sends the sensor signal to the detection timing control unit 15 .

Note that the first acquisition unit 11, the second acquisition unit 12, and the third acquisition unit 13 may acquire raw data (for example, analog signals) of sensor signals from each sensor, or may acquire sensor signals from each sensor. On the other hand, data that has undergone predetermined signal processing (for example, AD conversion processing or signal amplification processing) may be acquired.

The occupant determination unit 14 analyzes the presence state of an object in the vehicle U at the present time based on the sensor signal of the radio wave sensor 20 obtained at the present time, and determines the presence or absence of the occupant in the vehicle U from the analysis result. carry out the judgment. The timing of the determination processing of the occupant determination unit 14 is controlled by the detection timing control unit 15. In the vehicle occupant detection device 10, the determination result of the occupant determination unit 14 regarding the presence or absence of the occupant is transmitted into the vehicle U. indicates the presence or absence of child abandonment.

More specifically, as described with reference to FIG. 1, the occupant determination unit 14 performs frequency analysis of the sensor signal of the radio wave sensor 20 using a technique such as FFT, DCT (Discret Cosine Transform), or wavelet analysis. , and the presence or absence of an occupant in the vehicle U is determined based on the presence or absence of an object moving within the specific frequency range. For example, the occupant determination unit 14 uses a heat map obtained from the sensor signal of the radio wave sensor 20 to determine the breathing frequency of a person observed within an appropriate distance range (for example, about 0.5 m to 1.00 m) in the vehicle. The signal intensity (signal intensity in the R1 region in FIG. 1) of the component (for example, about 0.16 Hz to 1.00 Hz) is extracted, and the presence/absence of an occupant in the vehicle U is determined. For example, when the average value of the signal strength is equal to or higher than the threshold value, the occupant determination unit 14 determines that the vehicle U is in a manned state (a person is left behind in the vehicle), and the average value is less than the threshold value. In this case, it is determined that the inside of the vehicle U is in an unmanned state (there is no person left in the vehicle). Then, the occupant determination unit 14 sends the result of its own determination (that is, presence or absence of the occupant in the vehicle U) to the notification unit 16 .

The specific frequency range focused on by the occupant determination unit 14 includes, for example, a frequency range of 0.1 Hz or more and less than 1.0 Hz, which corresponds to a human breathing frequency band. Further, the specific distance range focused on by the occupant determination unit 14 includes, for example, a distance range of 0.5 m or more and less than 1.0 m, which corresponds to the distance range within the vehicle interior of the vehicle U from the radio wave sensor 20 .

When the occupant determination unit 14 determines that an occupant is present in the vehicle U (that is, when an occupant is left behind in the vehicle), the notification unit 16 activates the warning sound generator 51, the warning light generator 52, and the wireless communication device. At least one of 53 is used to notify the outside of the vehicle U of the determination result.

The notification unit 16 notifies the surroundings of the vehicle U that an object has been left behind in the vehicle by, for example, outputting a sound using the warning sound generator 51 . Further, the notification unit 16 notifies the surroundings of the vehicle U that an object has been left behind in the vehicle by outputting a warning light using the warning light generator 52, for example. In addition, the notification unit 16 notifies the user of the vehicle U that an object has been left behind in the vehicle by sending a text message to the terminal U1 of the user of the vehicle U using the wireless communication device 53, for example.

The vehicle occupant detection device 10 detects an abandoned person in the vehicle by the determination processing of the occupant determination unit 14 in this way. However, as described above, even when the vehicle U is stopped, external factors (for example, wind around the vehicle U, sound outside the vehicle U, external force from a person who touches the vehicle U, or Due to such minute vibrations of the vehicle U, the objects in the vehicle U sway in a way that is close to the breathing frequency. Such vibration of an object (an object other than a person) in the vehicle U is difficult to clearly distinguish from the respiratory motion of the occupant in the vehicle U from the sensor signal of the radio wave sensor 20. provoke judgment.

Therefore, the vehicle occupant detection device 10 has the function of the detection timing control section 15 in order to control the timing of executing the determination processing in the occupant determination section 14 .

The detection timing control unit 15 analyzes the current vibration state of the vehicle U based on the sensor signal of the vibration sensor 30, and when the vehicle U is not vibrating, permits the occupant determination unit 14 to perform determination, and controls the vehicle. When U is vibrating, execution of determination by the occupant determination unit 14 is not permitted.

More specifically, the detection timing control unit 15 performs frequency analysis of the sensor signal of the vibration sensor 30, and determines whether or not the vehicle U is vibrating with a magnitude equal to or greater than a threshold in a specific frequency range. 14 to switch permission/non-permission of the determination. Note that the method by which the detection timing control unit 15 performs the frequency analysis of the sensor signal of the vibration sensor 30 may be any method such as FFT, DCT, or wavelet analysis.

Note that the specific frequency range focused on by the detection timing control unit 15 is, for example, substantially the same frequency range as the specific frequency range focused on by the occupant determination unit 14 described above, and corresponds to, for example, at least the respiratory frequency band of a person. includes the frequency range above 0.1 Hz and below 1.0 Hz. As a result, it is possible to selectively disallow the execution of determination by the occupant determination unit 14 only at the timing when the vehicle U is vibrating to cause an erroneous determination by the occupant determination unit 14 .

However, the specific frequency range focused on by the detection timing control unit 15 may be different from the specific frequency range focused on by the occupant determination unit 14 . For example, the occupant determination unit 14 may focus on a specific frequency range of 0.16 Hz or more and 1.00 Hz, and the detection timing control unit 15 may focus on a specific frequency range of 0.10 Hz or more and 5.00 Hz. . That is, since the manner in which the load in the vehicle U vibrates depends on the natural vibration frequency of the load and the manner in which the vibration of the vehicle U is transmitted to the load, the specific frequency band focused on by the detection timing control unit 15 is , it may be set to a broader band than the specific frequency band focused on by the occupant determination unit 14, or a frequency shifted to the high-frequency side or the low-frequency side from the specific frequency band focused on by the occupant determination unit 14. It may be set to the band.

In addition to the sensor signal of the vibration sensor 30, the detection timing control unit 15 controls the permission/non-permission of the determination in the occupant determination unit 14, in addition to the sensor signal of the vibration sensor 30, the vehicle state detection sensor 40 (for example, the door lock of the vehicle U The occupant determination unit 14 refers to the sensor signal of the door lock sensor that detects the locking/unlocking of the vehicle U, and only when the vehicle U is in an abandoned state (a state in which the user, the driver, has left the vehicle U). Permission to make judgments in This is to prevent a situation in which an erroneous notification that a user has been left in the vehicle has occurred even though the user is present in the vehicle U.

In other words, the detection timing control unit 15 causes the occupant determination unit 14 to perform the determination only when the vehicle U is in the idle state and not vibrating in the specific frequency range at the present time. To give permission. Any method may be used by the detection timing control unit 15 to switch permission/non-permission of the determination in the occupant determination unit 14. For example, on/off control of the operation of the radio wave sensor 20, or A method such as on/off control of the operation of acquiring the sensor signal may be used.

However, the occupant determination unit 14 determines not only the timing at which the vehicle U is switched from the non-idle state to the left state (that is, the timing immediately after the vehicle U is left in the left state by the user), but also the timing at which the vehicle U is left in the left state. It is preferable to continuously perform such determination processing (for example, periodically at 10-minute intervals) while the passenger is in the vehicle U, and constantly monitor whether or not there is an occupant in the vehicle U (that is, whether or not an occupant has been left behind in the vehicle).

This is because, due to various factors, the occurrence of an object left in the vehicle may not be detected immediately after the vehicle U is left unattended by the user. For example, a child may get into the vehicle U after the vehicle U has been left unattended.

[Operation Flow of Vehicle Occupant Detection Device 10]
An example of the operation of the vehicle occupant detection device 10 according to this embodiment will be described below.

FIG. 4 is a flow chart showing an example of the operation of the vehicle occupant detection device 10. As shown in FIG. The flowchart shown in FIG. 4 is, for example, a process executed in order by the vehicle occupant detection device 10 according to a computer program.

First, in step S0, the vehicle occupant detection device 10 (detection timing control unit 15) waits for activation until a predetermined timing. Here, the activation timing of the abandoned vehicle detection system 1 (that is, the vehicle occupant detection device 10) includes, firstly, the timing when the vehicle U is switched from the non-left state to the left state. Periodic timing during idle conditions may be mentioned. The vehicle occupant detection device 10 detects the arrival of such timing based on the sensor signal of the vehicle state detection sensor 40 .

Next, in step S1, the vehicle occupant detection device 10 (detection timing control unit 15) activates the abandoned vehicle detection system 1 in response to the arrival of activation timing in step S0.

Next, in step S2, the vehicle occupant detection device 10 (detection timing control unit 15) acquires the sensor signal of the vibration sensor 30 via the second acquisition unit 12, and based on the sensor signal of the vibration sensor 30, the vehicle U is detected. measure the magnitude of the vibration of

In this step S2, the vehicle occupant detection device 10, for example, frequency-analyzes the sensor signal of the vibration sensor 30, and detects a specific frequency range of the vehicle U (for example, 0.16 Hz to 1.00 Hz, which is a human breathing frequency range). to extract the signal strength of Then, the vehicle occupant detection device 10 defines the average value of the signal strength of the respiratory frequency component as the magnitude of vibration of the vehicle U at the present time.

Next, in step S3, the vehicle occupant detection device 10 (detection timing control unit 15) sets the magnitude of vibration of the vehicle U to the first threshold value (however, the first threshold value is the magnitude of vibration of the vehicle U in step S5). It is determined whether or not it is less than the size that does not induce an erroneous determination in processing. Here, if the magnitude of vibration of the vehicle U is less than the threshold (step S3: YES), the vehicle occupant detection device 10 advances the process to step S4, and if the magnitude of vibration of the vehicle U is greater than or equal to the threshold (Step S3: NO), returning to step S2, the vibration state of the vehicle U is repeatedly monitored.

Next, in step S<b>4 , the vehicle occupant detection device 10 (occupant determination unit 14 ) acquires the sensor signal of the radio wave sensor 20 via the first acquisition unit 11 and performs object detection within the vehicle U.

Next, in step S5, the vehicle occupant detection device 10 (occupant determination unit 14) determines whether or not the vehicle has been left behind based on the sensor signal of the radio wave sensor 20 obtained in step S4. Then, the vehicle occupant detection device 10 (occupant determination unit 14) advances the process to step S6 if the vehicle has been left behind (step S5: YES), and if the vehicle has not been left (step S5: NO). ), without executing any particular process, it is set to the activation waiting state of step S0.

In step S5, the vehicle occupant detection device 10 (occupant determination unit 14), for example, analyzes the frequency of the sensor signal of the radio wave sensor 20, and determines the appropriate distance range (for example, about 0.5 m to 1.00 m) within the vehicle U. ), the signal intensity of the human respiratory frequency component (for example, about 0.16 Hz to 1.00 Hz) (R1 region in FIGS. 1A to 1C) is extracted. Then, the vehicle occupant detection device 10 detects that the average value of the signal strength in the R1 region is equal to or greater than the second threshold (where the second threshold is the signal strength for distinguishing between humans and objects other than humans), If it is determined that the vehicle has been left behind (step S5: YES), and if the average value is less than the second threshold value (step S5: NO), it is determined that the vehicle has not been left behind.

Next, in step S6, the vehicle occupant detection device 10 (notification unit 16) uses the wireless communication device 53 to notify the user's terminal U1 of the occurrence of being left behind in the vehicle. The surroundings of the vehicle U are notified using the device 52 .

[effect]
As described above, according to the vehicle occupant detection device 10 according to the present embodiment, external factors (for example, wind around the vehicle, sound outside the vehicle, external force from a person touching the vehicle, earthquake, etc.) When the vehicle U is vibrating, the process of judging the presence of a passenger using the sensor signal of the radio wave sensor 20 (that is, the child being left behind in the vehicle U) is not performed.

As a result, it is possible to accurately detect the occurrence of people being left behind in the car, and it is possible to avoid situations in which the user and pedestrians around the vehicle are unnecessarily confused by the output of an alarm that accompanies false detection of the occurrence of being left behind in the car. be.

(Modification)
By the way, at the timing immediately after the vehicle U is left in the state of being left by the user (for example, for several seconds after the sensor signal of the vehicle state detection sensor 40 starts to output the detection result related to the vehicle being left), the user may There is a possibility that the vibration of the vehicle U, which is generated with the opening and closing operation of the door of the vehicle U, remains. In that case, in the process flow according to the above embodiment, the vibration sensor 30 detects that the vibration of the vehicle U is equal to or greater than the threshold, and the occupant determination unit 14 waits for a certain period of time after the vehicle U is left unattended by the user. Since the determination process is not performed, there is a risk that the occurrence of an abandoned vehicle in the vehicle cannot be immediately detected.

Therefore, in the vehicle occupant detection device 10 according to the present modification, when the vibration of the vehicle U is continuously detected for a predetermined period of time (for example, 5 seconds), the detection timing control unit 15 performs exceptional processing, Once, the occupant determination unit 14 is caused to perform determination processing regarding the presence or absence of an occupant.

However, in this case, the radio wave sensor 20 is used to attempt to determine the presence or absence of a passenger in the vehicle U while the vehicle U is vibrating, so the reliability of the determination result is lower than usual. become a thing. From this point of view, the detection timing control unit 15 calculates the reliability of the determination by the occupant determination unit 14 according to the vibration state of the vehicle U when performing the above exception processing, and notifies the notification unit 16 of the occupant determination. The result of the determination by the occupant determination unit 14 is notified in a notification mode according to the reliability of the determination by the unit 14 .

FIG. 5 is a flowchart showing an example of the operation related to abandoned vehicle detection by the vehicle occupant detection device 10 according to the modification. The flowchart of FIG. 5 differs from the flowchart of FIG. 4 in that exceptional processing is added in steps S15 and S16, and notification processing is performed in steps S18 and S19.

FIG. 6 is a diagram showing a notification mode of the vehicle occupant detection device 10 according to the modification.

First, in step S0, the vehicle occupant detection device 10 (detection timing control unit 15) waits for activation until a predetermined timing. 15) activates the abandoned object detection system 1 .

Next, in step S12, the vehicle occupant detection device 10 (detection timing control unit 15) acquires the sensor signal of the vibration sensor 30 via the second acquisition unit 12, and based on the sensor signal of the vibration sensor 30, the vehicle U is detected. measure the magnitude of the vibration of

Next, in step S13, the vehicle occupant detection device 10 (detection timing control unit 15) sets the magnitude of vibration of the vehicle U to the first threshold value (however, the first threshold value is the magnitude of vibration of the vehicle U in step S5). It is determined whether or not it is less than the size that does not induce an erroneous determination in processing. Here, when the magnitude of vibration of the vehicle U is less than the threshold (step S13: YES), the vehicle occupant detection device 10 advances the process to step S14, performs object detection in the vehicle U, and detects the object in the vehicle U. If the magnitude of the vibration is greater than or equal to the threshold value (step S13: NO), the process returns to step S12 to repeatedly monitor the vibration state of the vehicle U.

However, if the determination result in step S13 is NO, the vehicle occupant detection device 10 updates the duration of the vibration of the vehicle U, and the duration of the vibration is equal to or greater than the threshold time (for example, 10 seconds). It is determined whether or not. Then, the vehicle occupant detection device 10 advances the flow to exception processing in steps S15 to S16 when the vibration duration of the vehicle U is equal to or greater than the threshold time, and when the vibration duration of the vehicle U is less than the threshold time, step Return to S12.

In the exception processing of steps S15 to S16, object detection in the vehicle U is performed using the sensor signal of the radio wave sensor 20 similar to step S14 (step S15), and the magnitude of vibration of the vehicle U measured in step S12 is detected. Then, a process of calculating the reliability of the abandonment determination process (meaning the determination process of step S5; the same shall apply hereinafter) is performed (step S16). The reliability of the abandoned vehicle determination process is stored in advance as a data table, for example, in association with the magnitude of vibration of the vehicle U (see FIG. 6). Such reliability is typically calculated such that the larger the vibration of the vehicle U, the lower the reliability, and the smaller the vibration of the vehicle U, the higher the reliability.

Next, in step S17, the vehicle occupant detection device 10 (occupant determination unit 14) determines whether or not the vehicle has been left behind based on the sensor signal of the radio wave sensor 20, as in step S5.

Next, in step S18, the vehicle occupant detection device 10 (occupant determination unit 14) determines the necessity of notification and the notification mode based on the determination result of the abandoned vehicle determination process and the reliability of the abandoned vehicle determination process.

In this step S18, the vehicle occupant detection device 10 (occupant determination unit 14), for example, firstly performs frequency analysis of the sensor signal of the radio wave sensor 20, and determines an appropriate distance range (for example, 0.5 m to 1 m) within the vehicle U. .00 m), the average value of the signal strength of the human respiratory frequency component (for example, about 0.16 Hz to 1.00 Hz) (R1 region in FIGS. 1A to 1C) is the second threshold (however, the second The second threshold determines whether or not notification is necessary depending on whether or not the signal strength is greater than or equal to the signal strength for distinguishing between a person and an object other than a person. Then, when notification is required, the vehicle occupant detection device 10 (occupant determination unit 14) notifies the user and the surroundings of the vehicle U based on the reliability of the abandonment determination process, as shown in FIG. determine the mode. Note that the sensor signal of the radio wave sensor 20 obtained in the process of step S14 is defined as having a reliability of 100%, for example.

As shown in FIG. 6, the mode of notification to the user and the mode of notification to the surroundings of the vehicle U typically increase as the reliability of the abandonment determination process increases (that is, as the vibration of the vehicle U decreases). The degree of attention grabbing of the user and/or people around the vehicle U is determined in a manner that is large. FIG. 6 shows a data table in which, as an example of a notification mode, the higher the reliability of the abandoned-abandonment determination process, the higher the frequency of notification to the user terminal, the louder the warning sound, and the like. there is

Next, in step S19, the vehicle occupant detection device 10 (notification unit 16) notifies the surroundings of the user's terminal U1 and the vehicle U of the occurrence of an abandoned vehicle, based on the notification mode determined in step S18.

As described above, according to the vehicle occupant detection device 10 according to the present modification, the vibration of the vehicle U caused by the opening and closing operation of the door of the vehicle U by the user remains when the vehicle occupant is left behind. Even if there is such a vehicle, it is possible to notify the user of the possibility of the occurrence of the vehicle being left behind.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

According to the vehicle occupant detection device according to the present disclosure, it is possible to detect a person left behind in a vehicle with higher accuracy.

1 abandoned detection system 10 vehicle occupant detection device 11 first acquisition unit 12 second acquisition unit 13 third acquisition unit 14 occupant determination unit 15 timing control unit 16 notification unit 20 radio wave sensor 30 vibration sensor 40 vehicle state detection sensor 51 warning sound generation Device 52 Warning light generator 53 Wireless communication device U Vehicle U1 User terminal

Claims (12)

a first acquisition unit that is mounted on a vehicle and acquires a sensor signal from a radio wave sensor that detects an object in the vehicle;
a second acquisition unit that is mounted on the vehicle and acquires a sensor signal of a vibration sensor that detects vibration of the vehicle;
an occupant determination unit that analyzes the existence state of an object in the vehicle at the current time based on the sensor signal of the radio wave sensor, and determines the presence or absence of an occupant in the vehicle from the analysis result;
Based on the sensor signal of the vibration sensor, the current vibration state of the vehicle is analyzed, and when the vehicle is not vibrating, execution of the determination by the occupant determination unit is permitted, and the vehicle is vibrating. a detection timing control unit that sometimes disallows execution of the determination by the occupant determination unit;
a notification unit that notifies the outside of the vehicle of the determination result of the occupant determination unit;
A vehicle occupant detection device comprising: The occupant determination unit performs frequency analysis of the sensor signal of the radio wave sensor, and determines whether an occupant is present in the vehicle based on the presence or absence of an object moving in a first specific frequency band in the vehicle. and
The detection timing control unit performs frequency analysis of the sensor signal of the vibration sensor, and determines whether or not the vehicle is vibrating with a magnitude equal to or greater than a threshold value in a second specific frequency band. to allow or disallow the implementation of
A vehicle occupant detection device according to claim 1. The first specific frequency band and the second specific frequency band include at least a frequency band corresponding to a human breathing frequency,
The vehicle occupant detection device according to claim 1 or 2. further comprising a third acquisition unit that acquires a sensor signal of a vehicle state detection sensor that is mounted on the vehicle and detects a state change related to whether the vehicle is left or not left by the user;
The detection timing control unit permits the occupant determination unit to perform the determination only when the vehicle is in an idle state based on a sensor signal from the vehicle state detection sensor.
A vehicle occupant detection device according to any one of claims 1 to 3. The occupant determination unit performs the determination at the timing when the vehicle is switched from the non-leaving state to the no-leaving state.
The vehicle occupant detection device according to claim 4. The occupant determination unit periodically performs the determination while the vehicle is left unattended.
The vehicle occupant detection device according to claim 4 or 5. The notification unit uses a warning sound generator or a warning light generator mounted on the vehicle to notify the surroundings of the vehicle of the result of the determination by the occupant determination unit.
A vehicle occupant detection device according to any one of claims 1 to 6. The notification unit uses a wireless communication device mounted on the vehicle to notify the user of the result of the determination by the occupant determination unit.
A vehicle occupant detection device according to any one of claims 1 to 7. When the vibration of the vehicle is continuously detected over a predetermined period of time based on the sensor signal of the vibration sensor, the detection timing control unit temporarily causes the occupant determination unit to perform the determination, and calculating the reliability of the determination by the occupant determination unit according to the vibration state of the vehicle,
The notification unit notifies the result of the determination by the occupant determination unit in a notification mode according to the reliability of the determination by the occupant determination unit.
A vehicle occupant detection device according to any one of claims 1 to 8. The detection timing control unit permits/disallows execution of the determination by the occupant determination unit by on/off control of the operation of the radio wave sensor or on/off control of the operation of acquiring a sensor signal from the radio wave sensor. toggle permissions,
A vehicle occupant detection device according to any one of claims 1 to 9. A first process of acquiring a sensor signal of a radio wave sensor mounted on a vehicle and detecting an object in the vehicle;
a second process of acquiring a sensor signal of a vibration sensor mounted on the vehicle and detecting vibration of the vehicle;
a third process of analyzing the existence state of an object in the vehicle at the current time based on the sensor signal of the radio wave sensor, and determining the presence or absence of an occupant in the vehicle from the analysis result;
Based on the sensor signal of the vibration sensor, the current vibration state of the vehicle is analyzed, and when the vehicle is not vibrating, execution of the determination in the third process is permitted, and the vehicle is vibrating. a fourth process that sometimes disallows execution of the determination in the third process;
a fifth process for informing the outside of the vehicle of the determination result of the third process;
A vehicle occupant detection method comprising: to the computer,
A first process of acquiring a sensor signal of a radio wave sensor mounted on a vehicle and detecting an object in the vehicle;
a second process of acquiring a sensor signal of a vibration sensor mounted on the vehicle and detecting vibration of the vehicle;
a third process of analyzing the state of existence of an object in the vehicle at the current point in time based on the sensor signal of the radio wave sensor, and determining the presence or absence of an occupant in the vehicle from the analysis result;
Based on the sensor signal of the vibration sensor, the current vibration state of the vehicle is analyzed, and when the vehicle is not vibrating, execution of the determination in the third process is permitted, and the vehicle is vibrating. a fourth process that sometimes disallows execution of the determination in the third process;
a fifth process for informing the outside of the vehicle of the determination result of the third process;
A vehicle occupant detection program that runs a

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