Vehicle occupant detection device, vehicle occupant detection method, and vehicle occupant detection program

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

Technical Field

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[0001] The present disclosure relates to a vehicle occupant detection device, a vehicle occupant detection method, and a vehicle occupant detection program.

Background Art

[0002] Conventionally, there has been a case where a caregiver leaves the child in the vehicle interior and goes outside, forgetting that the child is still in the vehicle interior, resulting in the abandonment (long-term neglect) of the child in the vehicle interior. As a result, serious health damage such as heatstroke has occurred.

[0003] Therefore, a detection system for abandonment that detects that a child has been left unattended in a vehicle and issues an alarm has begun to be installed in vehicles. In such a system, when the caregiver attempts to leave the vehicle, the presence or absence of a living body such as a child in the vehicle is detected. When it is determined that a living body is present in the vehicle, an alarm is issued outside the vehicle, such as a horn or hazard, or a notification is sent to the caregiver's smartphone or the like.

[0004] For example, Patent Document 1 describes an occupant state detection system that notifies an alarm when a person is left in a vehicle. Specifically, the occupant state detection system detects whether a state of leaving the seat, where a person leaves the front seat (driver's seat or passenger seat), has occurred. When the occurrence of the leaving state is detected, if an object in the detection target area in the vehicle interior is determined to be a person, an alarm is output.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, in recent years, the use of radio wave sensors has been considered as a means of detecting the presence of a person inside a vehicle in this type of abandoned vehicle detection system (see, for example, Patent Document 1). A radio wave sensor is, for example, mounted on the ceiling inside a vehicle and transmits radio waves (transmitted waves) to a detection target area inside the vehicle, and receives radio waves (reflected waves) reflected by objects within the detection target area, thereby detecting objects present inside the vehicle.

[0007] This type of abandoned child detection system requires the ability to continuously detect whether a child has been left unattended inside the vehicle (hereinafter referred to as "unattended inside the vehicle") while the vehicle is stopped (i.e., while the vehicle is parked). In this respect, an abandoned child detection system using radio wave sensors is useful because, unlike occupant detection using weight sensors or pressure sensors, it directly distinguishes between people and non-human objects (e.g., luggage) based on human movement, allowing for highly accurate and easy detection of unattended children inside the vehicle even while the vehicle is parked.

[0008] In abandoned vehicle detection systems using radio wave sensors, the presence of a person inside a vehicle is typically detected by determining whether the sensor signal from the radio wave sensor contains a human respiratory frequency component (for example, around 0.16 Hz to 1.00 Hz). This detection method utilizes the fact that a person's (for example, a child's) body normally fluctuates at the respiratory frequency, and by extracting the signal strength of this frequency component from the sensor signal from the radio wave sensor, it is possible to distinguish whether an object inside the vehicle is a person or something other than a person.

[0009] Figure 1 illustrates the detection process related to the presence or absence of occupants in an abandoned vehicle detection system using radio wave sensors. Figure 1A shows an example of a heat map obtained from the sensor signal of the radio wave sensor when there is no person inside the vehicle. Figure 1B shows an example of a heat map obtained from the sensor signal of the radio wave sensor when there is a person inside the vehicle. Figure 1C shows an example of a heat map obtained from the sensor signal of the radio wave sensor when there is no person inside the vehicle and the vehicle is vibrating slightly (more precisely, when objects inside the vehicle are vibrating due to the slight vibration of the vehicle). Note that the heat maps in Figures 1A to 1C were all generated based on the sensor signals of the radio wave sensor acquired while the vehicle was stationary.

[0010] From the sensor signal of a radio wave sensor, it is possible to determine the distance from the sensor to the detected object and the frequency of the detected object's movement. One example of a method for extracting the respiratory frequency component from the sensor signal of a radio wave sensor is a method using FFT (Fast Fourier Transform). When this is applied to the sensor signal of a radio wave sensor, the sensor signal can be converted into a "heatmap" such as Figures 1A to 1C, which is calculated as frequency (i.e., frequency component of the sensor signal) × distance (i.e., distance from the radio wave sensor to the detected object) × signal intensity (brightness of each region of the heatmap).

[0011] In the detection process for the presence or absence of occupants, for example, the signal intensity of the respiratory frequency component of a person observed within a suitable distance range inside the vehicle (e.g., approximately 0.5m to 1.00m) (e.g., the R1 region in Figures 1A to 1C) is extracted from this heatmap to determine whether the vehicle is occupied or unoccupied. As can be seen by referring to Figures 1A and 1B, when a person is present inside the vehicle (Figure 1B), the signal intensity in the R1 region is observed to be stronger compared to when no one is present inside the vehicle (Figure 1A).

[0012] However, while researching and developing an abandoned vehicle detection system using such radio wave sensors, the inventors of this invention have found that even when a vehicle is stationary, it frequently vibrates slightly due to external factors (for example, wind around the vehicle, sounds outside the vehicle, external forces from people touching the vehicle, or earthquakes, etc.), and that these slight vibrations of the vehicle cause objects inside the vehicle to vibrate in a manner close to the breathing frequency (for example, around 0.16 Hz to 1.00 Hz). Examples of objects inside a vehicle that are prone to vibration due to slight vibrations of the vehicle include liquids in plastic bottles, luggage suspended inside the vehicle, shopping bags containing goods, and baskets containing luggage.

[0013] Figure 1C shows that, due to the shaking of objects inside the vehicle, a strong signal intensity was observed in the R1 region of the heatmap, similar to the case where a person is present inside the vehicle (Figure 1B). As a result, even when the vehicle is unoccupied, it may be mistakenly detected as being occupied (i.e., someone has been left behind inside the vehicle), potentially leading to unnecessary alarms being triggered.

[0014] This disclosure has been made in view of the above-mentioned problems and aims to provide a vehicle occupant detection device, a vehicle occupant detection method, and a vehicle occupant detection program that can detect unattended persons in vehicles with higher accuracy. [Means for solving the problem]

[0015] The main disclosure that addresses the aforementioned issues is: A first acquisition unit is mounted on a vehicle and acquires sensor signals from a radio wave sensor that detects objects inside the vehicle, A second acquisition unit is mounted on the vehicle and acquires the sensor signal of a vibration sensor that detects vibrations of the vehicle, An occupant determination unit analyzes the current state of presence of objects inside the vehicle based on the sensor signal of the aforementioned radio wave sensor, and determines whether or not there are occupants inside the vehicle based on the analysis results. A detection timing control unit analyzes the current vibration state of the vehicle based on the sensor signal of the vibration sensor, permits the occupant determination unit to perform the determination when the vehicle is not vibrating, and disallows the occupant determination unit to perform the determination when the vehicle is vibrating. A notification unit that notifies the occupant determination unit of the determination result to the outside of the vehicle, This is a vehicle occupant detection device equipped with [specific features / features].

[0016] Also, in other situations, A first process for acquiring sensor signals from a radio wave sensor mounted on a vehicle that detects objects inside the vehicle, A second process for acquiring the sensor signal of a vibration sensor mounted on the vehicle and used to detect vibrations of the vehicle, A third process involves analyzing the presence status of objects inside the vehicle at the current time based on the sensor signal of the aforementioned radio wave sensor, and determining whether or not there are occupants inside the vehicle based on the analysis results. A fourth process analyzes the current vibration state of the vehicle based on the sensor signal of the vibration sensor, permits the execution of the determination in the third process if the vehicle is not vibrating, and denies the execution of the determination in the third process if the vehicle is vibrating. A fifth process which notifies the determination result of the third process to the outside of the vehicle, This is a vehicle occupant detection method that has the following characteristics:

[0017] Also, in other situations, On the computer, A first process for acquiring sensor signals from a radio wave sensor mounted on a vehicle that detects objects inside the vehicle, A second process for acquiring the sensor signal of a vibration sensor mounted on the vehicle and used to detect vibrations of the vehicle, A third process involves analyzing the presence status of objects inside the vehicle at the current time based on the sensor signal of the aforementioned radio wave sensor, and determining whether or not there are occupants inside the vehicle based on the analysis results. Based on the sensor signal of the vibration sensor, analyze the vibration state of the vehicle at the current time. When the vehicle is not vibrating, permit the execution of the determination in the third process, and when the vehicle is vibrating, do not permit the execution of the determination in the third process. This is the fourth process, The fifth process of notifying the determination result of the third process outside the vehicle, It is a vehicle occupant detection program that causes these to be executed.

Effect of the Invention

[0018] According to the vehicle occupant detection device according to the present disclosure, it is possible to detect vehicle abandonment with higher accuracy.

Brief Description of the Drawings

[0019] [Figure 1] A diagram for explaining the detection process related to the presence or absence of an occupant in an abandonment detection system using a radio wave sensor [Figure 2] A diagram showing an example of the configuration of an abandonment detection system according to an embodiment of the present invention [Figure 3] A diagram showing an example of the configuration of a vehicle occupant detection device according to an embodiment of the present invention [Figure 4] A flowchart showing an example of the operation of a vehicle occupant detection device according to an embodiment of the present invention [Figure 5] A flowchart showing an example of the operation of a vehicle occupant detection device according to a modification of the present invention [Figure 6] A diagram showing the notification mode during exception handling of a vehicle occupant detection device according to a modification of the present invention

Embodiment for Carrying Out the Invention

[0020] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same function are denoted by the same reference numerals, and redundant description is omitted.

[0021] The following describes an abandoned object detection system according to one embodiment of the present invention (hereinafter referred to as "abandoned object detection system 1").

[0022] Figure 2 shows an example of the configuration of the abandoned item detection system 1.

[0023] The abandoned child detection system 1 is installed in vehicle U and is used to prevent situations where, for example, a parent and child are in vehicle U, and the parent gets out of the vehicle (specifically, inside the cabin) and forgets that the child is still inside, thus leaving the child unattended inside the cabin. Vehicle U is, for example, a passenger car capable of carrying multiple occupants.

[0024] The abandoned vehicle detection system 1 includes a vehicle occupant detection device 10, a radio wave sensor 20, a vibration sensor 30, a vehicle status detection sensor 40, a warning sound generator 51, a warning light generator 52, and a wireless communication device 53.

[0025] The abandoned child detection system 1 is configured such that the vehicle occupant detection device 10 determines whether or not a child has been left behind inside the vehicle U based on sensor signals from the radio wave sensor 20, vibration sensor 30, and vehicle state detection sensor 40. If the determination shows that a child has been left behind, the system uses a warning sound generator 51, a warning light generator 52, and a wireless communication device 53 to notify the outside of the vehicle U.

[0026] The radio wave sensor 20 transmits radio waves (transmitted waves) to a detection target area inside the vehicle U, and receives radio waves (reflected waves) reflected by objects within the detection target area. Based on the time difference between the time it takes for the transmitted radio waves to be reflected by the objects and return, the sensor determines the distance from the radio wave sensor 20 to the object and the relative velocity between the radio wave sensor 20 and the object. In other words, the radio wave sensor 20 outputs a sensor signal corresponding to the object's location, shape, and movement. For example, the radio wave sensor 20 is mounted on the ceiling inside the vehicle U and detects objects located in the rear seats of the vehicle. The radio wave sensor 20 then transmits the sensor signal related to the object it detected to the vehicle occupant detection device 10.

[0027] The type of sensor used in the radio wave sensor 20 is not particularly limited, but for example, a Doppler sensor can be used as such a radio wave sensor 20. A Doppler sensor transmits radio waves of a predetermined frequency as a transmitted wave toward the detection area, receives the radio waves reflected by an object within the detection area as a received wave, and outputs a sensor signal of a Doppler frequency corresponding to the difference in frequency between the transmitted wave and the received wave. If the object that reflected the transmitted wave is moving or in motion, the frequency of the received wave shifts according to the speed of the object due to the Doppler effect. Therefore, the speed of the object can be determined based on the sensor signal of the radio wave sensor 20. For example, if the object is a person, by determining the speed of the object, not only the speed of movement of the person but also biological information such as the person's respiratory movements can be obtained as part of the person's movement. The frequency band of the radio waves used in the radio wave sensor 20 is, for example, the millimeter wave band or the giga wave band.

[0028] The vibration sensor 30 is installed inside the vehicle U (for example, on the bottom plate of the vehicle U) and detects vibrations of the vehicle U. As described above, even when the vehicle U is stationary, it frequently experiences slight vibrations due to external factors (for example, wind around the vehicle, sounds from outside the vehicle, external forces from people touching the vehicle, or earthquakes, etc.). The vibration sensor 30 detects the vibration state of the vehicle U itself (i.e., 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.

[0029] The type of vibration sensor 30 is not particularly limited as long as it can directly detect vibrations of the vehicle U, but for example, a 3-axis acceleration sensor can be used as such a vibration sensor 30. The 3-axis acceleration sensor detects acceleration due to vibration for each of the three mutually orthogonal axes fixed to the vibration sensor 30, and outputs a sensor signal representing the acceleration of each of the three axes.

[0030] The vehicle status detection sensor 40 detects the state of whether the vehicle U is left unattended or not by the user. The vehicle status detection sensor 40 is composed of, for example, a door lock sensor that detects the locking / unlocking of the vehicle U's doors, and by detecting that the vehicle U is locked from the outside, it detects that the vehicle U is in an unattended state (meaning the state in which the user, who is the driver, leaves the vehicle U; the same applies hereinafter). The vehicle status detection sensor 40 may be composed of, for example, a seat belt fastening / unfastening sensor, a key on / key off sensor, etc., instead of the door lock sensor, or together with the door lock sensor.

[0031] The warning sound generator 51, the warning light generator 52, and the wireless communication device 53 are notification means provided on the vehicle U. Here, the warning sound generator 51 is, for example, a speaker capable of notifying the area around the vehicle U of an abnormal situation by sound. The warning light generator 52 is, for example, a headlamp and / or taillamp capable of notifying the area around the vehicle U of an abnormal situation by lighting up. 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 an abnormal situation by wireless communication.

[0032] The vehicle occupant detection device 10 is a signal processing device that detects the occurrence of an unattended person inside a vehicle based on the sensor signals from the radio wave sensor 20, the vibration sensor 30, and the vehicle status detection sensor 40. If an unattended person is found inside the vehicle, the vehicle occupant detection device 10 notifies the outside of the vehicle U using a warning sound generator 51, a warning light generator 52, and a wireless communication device 53. The vehicle occupant detection device 10 is housed, for example, inside the dashboard of the vehicle U.

[0033] The vehicle occupant detection device 10 communicates with each part of the abandoned vehicle detection system 1 (in this case, the radio wave sensor 20, vibration sensor 30, vehicle status detection sensor 40, warning sound generator 51, warning light generator 52, and wireless communication device 53) and provides overall control of the abandoned vehicle detection system 1. The vehicle occupant detection device 10 includes, for example, a CPU (Central Processing Unit) as a processor, a storage medium such as ROM (Read Only Memory) storing the control program, a working memory such as RAM (Random Access Memory), and a communication circuit. In this case, the functions of each of the above-mentioned parts are realized by the CPU executing the control program.

[0034] The vehicle occupant detection device 10, radio wave sensor 20, vibration sensor 30, vehicle status detection sensor 40, warning sound generator 51, warning light generator 52, and wireless communication device 53 are interconnected, for example, via an in-vehicle network (for example, a communication network compliant with the CAN communication protocol), enabling them to send and receive necessary data and control signals to and from each other.

[0035] Furthermore, the vehicle occupant detection device 10, radio wave sensor 20, vibration sensor 30, vehicle status detection sensor 40, warning sound generator 51, warning light generator 52, and wireless communication device 53 are configured to operate continuously even when the vehicle U is stopped (i.e., when the key is off), by receiving power from, for example, an onboard battery installed in the vehicle U.

[0036] [Detailed configuration of the vehicle occupant detection device 10] Here, we will explain the detailed configuration of the vehicle occupant detection device 10.

[0037] Figure 3 shows an example of the configuration of the vehicle occupant detection device 10.

[0038] The vehicle occupant detection device 10 includes 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.

[0039] The first acquisition unit 11 acquires the sensor signal from the radio wave sensor 20 and sends the sensor signal to the crew determination unit 14.

[0040] The second acquisition unit 12 acquires the sensor signal from the vibration sensor 30 and sends the sensor signal to the detection timing control unit 15.

[0041] The third acquisition unit 13 acquires the sensor signal from the vehicle state detection sensor 40 and sends the sensor signal to the detection timing control unit 15.

[0042] Furthermore, the first acquisition unit 11, the second acquisition unit 12, and the third acquisition unit 13 may acquire raw data (e.g., analog signals) of the sensor signals from each sensor, or they may acquire data on which predetermined signal processing (e.g., AD conversion processing or signal amplification processing) has been applied to the sensor signals of each sensor.

[0043] The occupant determination unit 14 analyzes the current state of objects inside the vehicle U based on the sensor signals from the radio wave sensor 20 obtained at the present time, and determines whether or not there are occupants inside the vehicle U based on the analysis results. The timing of the determination process by the occupant determination unit 14 is controlled by the detection timing control unit 15, and the vehicle occupant detection device 10 indicates whether or not a child has been left unattended inside the vehicle U based on the determination result of the occupant determination unit 14 regarding the presence or absence of occupants.

[0044] More specifically, as explained with reference to Figure 1, the occupant determination unit 14 performs frequency analysis of the sensor signal of the radio wave sensor 20 using methods such as FFT, DCT (Discret Cosine Transform), or wavelet analysis, and determines the presence or absence of an occupant in the vehicle U based on the presence or absence of an object moving within a specific frequency range within the vehicle U. For example, the occupant determination unit 14 uses a heat map obtained from the sensor signal of the radio wave sensor 20 to extract the signal intensity (signal intensity in the R1 region of Figure 1) of the human respiratory frequency component (e.g., approximately 0.16 Hz to 1.00 Hz) observed within an appropriate distance range (e.g., approximately 0.5 m to 1.00 m) inside the vehicle, and determines the presence or absence of an occupant in the vehicle U. For example, if the average value of such signal intensity is above a threshold, the occupant determination unit 14 determines that the vehicle U is occupied (a person has been left behind inside the vehicle), and if the average value is below the threshold, the occupant determination unit 14 determines that the vehicle U is unoccupied (a person has not been left behind inside the vehicle). The occupant determination unit 14 then sends the result of its determination (i.e., whether or not there are occupants inside the vehicle U) to the notification unit 16.

[0045] Furthermore, the specific frequency range focused on by the occupant determination unit 14 includes, for example, a frequency range of 0.1 Hz or higher and less than 1.0 Hz, which corresponds to the human respiratory frequency band. Also, the specific distance range focused on by the occupant determination unit 14 includes, for example, a distance range of 0.5 m or higher and less than 1.0 m, which corresponds to the distance range from the radio wave sensor 20 to the interior of the vehicle U.

[0046] If the occupant determination unit 14 determines that an occupant is present inside the vehicle U (i.e., if an unattended passenger has been found inside the vehicle), the notification unit 16 uses at least one of the warning sound generator 51, the warning light generator 52, and the wireless communication device 53 to notify the determination result to the outside of the vehicle U.

[0047] The notification unit 16 notifies the vicinity of vehicle U that an unattended person has been left inside the vehicle by, for example, outputting sound using a warning sound generator 51. The notification unit 16 also notifies the vicinity of vehicle U that an unattended person has been left inside the vehicle by, for example, outputting warning light using a warning light generator 52. The notification unit 16 also notifies the user of vehicle U that an unattended person has been left inside the vehicle by, for example, sending a text message to the user's terminal U1 using a wireless communication device 53.

[0048] The vehicle occupant detection device 10 detects that a person has been left behind inside the vehicle through the determination process of the occupant determination unit 14. However, as described above, even when the vehicle U is stationary, it frequently vibrates slightly due to external factors (for example, wind around the vehicle U, sounds outside the vehicle U, external forces from people touching the vehicle U, or earthquakes, etc.), and as a result of these slight vibrations of the vehicle U, objects inside the vehicle U vibrate in a manner close to the breathing frequency. Such vibrations of objects inside the vehicle U (objects other than people) are difficult to clearly distinguish from the breathing movements of occupants inside the vehicle U from the sensor signals of the radio wave sensor 20, which induces misjudgment in the occupant determination unit 14.

[0049] Therefore, the vehicle occupant detection device 10 has the function of a detection timing control unit 15 in order to control the timing at which the occupant determination unit 14 performs the determination process.

[0050] The detection timing control unit 15 analyzes the current vibration state of the vehicle U based on the sensor signal from the vibration sensor 30. If the vehicle U is not vibrating, it permits the occupant determination unit 14 to perform the determination. If the vehicle U is vibrating, it denies the occupant determination unit 14 to perform the determination.

[0051] More specifically, the detection timing control unit 15 performs frequency analysis of the sensor signal from the vibration sensor 30 and switches the occupant determination unit 14's decision-making process between allowing and disallowing the decision based on whether the vehicle U is vibrating at a magnitude exceeding a threshold within a specific frequency range. The method used by the detection timing control unit 15 to perform frequency analysis of the sensor signal from the vibration sensor 30 may be any method, such as FFT, DCT, or wavelet analysis.

[0052] Furthermore, 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 includes, for example, a frequency range of at least 0.1 Hz and less than 1.0 Hz, which corresponds to the human respiratory frequency band. This makes it possible to selectively deny the occupant determination unit 14 from performing its determination only at the timing when vibrations that induce a false determination are occurring in the vehicle U.

[0053] However, the specific frequency range focused on by the detection timing control unit 15 may differ from the specific frequency range focused on by the occupant determination unit 14. For example, the specific frequency range focused on by the occupant determination unit 14 may be 0.16 Hz or higher and 1.00 Hz, while the specific frequency range focused on by the detection timing control unit 15 may be 0.10 Hz or higher and 5.00 Hz. In other words, since the way in which cargo inside the vehicle U vibrates depends on the natural vibration frequency of the cargo and the way in which the vibration of the vehicle U is transmitted to the cargo, the specific frequency band focused on by the detection timing control unit 15 may be set to a broader band than the specific frequency band focused on by the occupant determination unit 14, or it may be set to a frequency band shifted to the higher or lower frequency side from the specific frequency band focused on by the occupant determination unit 14.

[0054] Furthermore, when the detection timing control unit 15 controls whether to permit or deny the occupant determination unit 14 to perform a determination, it refers to the sensor signal of the vehicle state detection sensor 40 (for example, a door lock sensor that detects the locking / unlocking of the vehicle U's doors) in addition to the sensor signal of the vibration sensor 30, and permits the occupant determination unit 14 to perform a determination only when the vehicle U is in an abandoned state (the user, who is the driver, has left the vehicle U). This is to prevent situations in which the system mistakenly reports that a user has been left behind in the vehicle even though the user is actually inside the vehicle U.

[0055] In other words, the detection timing control unit 15 permits the occupant determination unit 14 to perform a determination only if the current state of the vehicle U is idle and not vibrating within a specific frequency range. The method by which the detection timing control unit 15 switches between permitting and denying the occupant determination unit 14 to perform a determination is arbitrary and may include, for example, on / off control of the operation of the radio wave sensor 20, or on / off control of the operation of acquiring sensor signals from the radio wave sensor 20.

[0056] However, it is preferable that the occupant determination unit 14 continuously performs this determination process not only at the moment when the vehicle U switches from an idle state to an idle state (i.e., immediately after the vehicle U is designated as an idle state by the user), but also while the vehicle U is in an idle state (for example, regularly at 10-minute intervals), and constantly monitors whether or not there are occupants inside the vehicle U (i.e., whether or not an unattended passenger has been left inside the vehicle).

[0057] This is because, due to various factors, the occurrence of a child being left unattended in a vehicle may not be detected immediately after the vehicle U is left unattended by the user. For example, a child may get into vehicle U after it has been left unattended.

[0058] [Operation flow of the vehicle occupant detection device 10] The following describes an example of the operation of the vehicle occupant detection device 10 according to this embodiment.

[0059] Figure 4 is a flowchart illustrating an example of the operation of the vehicle occupant detection device 10. The flowchart shown in Figure 4 represents, for example, the processes that the vehicle occupant detection device 10 executes sequentially according to a computer program.

[0060] First, in step S0, the vehicle occupant detection device 10 (detection timing control unit 15) waits to be activated until a predetermined timing. Here, the activation timing for the abandoned vehicle detection system 1 (i.e., the vehicle occupant detection device 10) is, firstly, the timing when the vehicle U switches from an idle state to an abandoned state, and secondly, periodic timings while the vehicle U is in an abandoned state. The vehicle occupant detection device 10 detects the arrival of such timings based on the sensor signal from the vehicle state detection sensor 40.

[0061] 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 the activation timing in step S0.

[0062] Next, in step S2, the vehicle occupant detection device 10 (detection timing control unit 15) acquires the sensor signal from the vibration sensor 30 via the second acquisition unit 12 and measures the magnitude of the vibration of the vehicle U based on the sensor signal from the vibration sensor 30.

[0063] In step S2, the vehicle occupant detection device 10, for example, performs frequency analysis on the sensor signal of the vibration sensor 30 and extracts the signal intensity within a specific frequency range of the vehicle U (for example, the human breathing frequency range of 0.16 Hz - 1.00 Hz). The vehicle occupant detection device 10 then defines the average value of the signal intensity of the breathing frequency component as the magnitude of vibration of the vehicle U at that moment.

[0064] Next, in step S3, the vehicle occupant detection device 10 (detection timing control unit 15) determines whether the magnitude of vibration of the vehicle U is less than a first threshold (where the first threshold is a magnitude such that the magnitude of vibration of the vehicle U does not induce a false judgment in the processing of step S5). Here, if the magnitude of vibration of the vehicle U is less than the threshold (step S3: YES), the vehicle occupant detection device 10 proceeds to step S4, and if the magnitude of vibration of the vehicle U is greater than or equal to the threshold (step S3: NO), it returns to step S2 and repeatedly monitors the vibration state of the vehicle U.

[0065] Next, in step S4, the vehicle occupant detection device 10 (occupant determination unit 14) acquires the sensor signal from the radio wave sensor 20 via the first acquisition unit 11 and performs object detection inside the vehicle U.

[0066] Next, in step S5, the vehicle occupant detection device 10 (occupant determination unit 14) determines whether or not a person has been left behind in the vehicle based on the sensor signal from the radio wave sensor 20 obtained in step S4. If a person has been left behind in the vehicle (step S5: YES), the vehicle occupant detection device 10 (occupant determination unit 14) proceeds to step S6, and if a person has not been left behind in the vehicle (step S5: NO), it does not perform any particular processing and returns to the startup waiting state of step S0.

[0067] In step S5, the vehicle occupant detection device 10 (occupant determination unit 14) performs frequency analysis on the sensor signal of the radio wave sensor 20, for example, and extracts the signal intensity of the respiratory frequency component of a person observed within an appropriate distance range (for example, about 0.5m to 1.00m) inside the vehicle U (for example, the R1 region in Figures 1A to 1C). The vehicle occupant detection device 10 then determines that a person has been left behind in the vehicle if the average value of the signal intensity in the R1 region is equal to or greater than the second threshold (where the second threshold is the signal intensity for distinguishing between a person and an object other than a person) (step S5: YES), and determines that a person has not been left behind in the vehicle if the average value is less than the second threshold (step S5: NO).

[0068] Next, in step S6, the vehicle occupant detection device 10 (notification unit 16) notifies the user's terminal U1 of the occurrence of an unattended person inside the vehicle using the wireless communication device 53, and also notifies the area around the vehicle U using the warning sound generator 51 and the warning light generator 52.

[0069] [effect] As described above, the vehicle occupant detection device 10 according to this embodiment is configured not to perform the process of determining the presence of an occupant (i.e., a child left unattended inside the vehicle U) using the sensor signal of the radio wave sensor 20 when vibration occurs in the vehicle U due to external factors (for example, wind around the vehicle, sounds outside the vehicle, external force from a person touching the vehicle, or an earthquake, etc.).

[0070] This makes it possible to accurately detect instances of children being left unattended in vehicles, and to avoid situations where false alarms caused by incorrect detections of children being left unattended in vehicles unnecessarily confuse users and pedestrians around the vehicle.

[0071] (modified version) However, immediately after the vehicle U is left unattended by the user (for example, for a few seconds after the sensor signal of the vehicle state detection sensor 40 begins to output a detection result related to the vehicle being left unattended), there is a possibility that vibrations of the vehicle U generated by the user opening and closing the doors of the vehicle U may remain. In that case, in the processing flow according to the above embodiment, the vibration sensor 30 may detect that the vibration of the vehicle U is above a threshold, and the judgment processing in the occupant determination unit 14 may not be performed for a certain period of time after the vehicle U is left unattended by the user, and there is a possibility that the occurrence of being left unattended in the vehicle cannot be detected immediately.

[0072] Therefore, in the modified vehicle occupant detection device 10, if the vibration of the vehicle U is detected continuously for a predetermined time (for example, 5 seconds), the detection timing control unit 15, as an exception, causes the occupant determination unit 14 to perform a determination process regarding the presence or absence of an occupant.

[0073] However, in that case, since the presence or absence of an occupant inside the vehicle U is being determined using the radio wave sensor 20 while the vehicle U is vibrating, the determination result will be less reliable than usual. From this perspective, when the above exception processing is performed, the detection timing control unit 15 calculates the reliability of the determination made by the occupant determination unit 14 according to the vibration state of the vehicle U, and instructs the notification unit 16 to notify the result of the determination made by the occupant determination unit 14 in a notification manner corresponding to the reliability of the determination made by the occupant determination unit 14.

[0074] Figure 5 is a flowchart showing an example of the operation of the modified vehicle occupant detection device 10 related to abandoned vehicle detection. Note that the flowchart in Figure 5 differs from the flowchart in Figure 4 in that exception handling is added in steps S15 to S16, and notification processing is performed in steps S18 to S19.

[0075] Figure 6 shows the notification mode of the vehicle occupant detection device 10 according to a modified example.

[0076] First, in step S0, the vehicle occupant detection device 10 (detection timing control unit 15) waits to be activated until a predetermined timing, and in step S11, in response to the arrival of the activation timing, the vehicle occupant detection device 10 (detection timing control unit 15) activates the abandoned vehicle detection system 1.

[0077] Next, in step S12, the vehicle occupant detection device 10 (detection timing control unit 15) acquires the sensor signal from the vibration sensor 30 via the second acquisition unit 12 and measures the magnitude of the vibration of the vehicle U based on the sensor signal from the vibration sensor 30.

[0078] Next, in step S13, the vehicle occupant detection device 10 (detection timing control unit 15) determines whether the magnitude of vibration of the vehicle U is less than a first threshold (where the first threshold is a magnitude such that the magnitude of vibration of the vehicle U does not induce a false judgment in the processing of step S5). Here, if the magnitude of vibration of the vehicle U is less than the threshold (step S13: YES), the vehicle occupant detection device 10 proceeds to step S14 and performs object detection inside the vehicle U. If the magnitude of vibration of the vehicle U is greater than or equal to the threshold (step S13: NO), it returns to step S12 and repeatedly monitors the vibration state of the vehicle U.

[0079] However, if the result in step S13 is NO, the vehicle occupant detection device 10 updates the duration of vibration of vehicle U and determines whether the duration of vibration is equal to or greater than a threshold time (for example, 10 seconds). If the duration of vibration of vehicle U is equal to or greater than the threshold time, the vehicle occupant detection device 10 proceeds to the exception handling in steps S15 to S16. If the duration of vibration of vehicle U is less than the threshold time, it returns to step S12.

[0080] In the exception handling steps S15-S16, object detection within the vehicle U is performed using the sensor signal of the radio wave sensor 20, similar to step S14 (step S15), and the reliability of the abandoned object determination process (meaning the determination process in step S5; the same applies hereafter) is calculated from the magnitude of the vibration of the vehicle U measured in step S12 (step S16). The reliability of the abandoned object determination process is stored in advance as a data table associated with the magnitude of the vibration of the vehicle U (see Figure 6). Typically, this reliability is calculated such that the greater the vibration of the vehicle U, the lower the reliability, and the smaller the vibration of the vehicle U, the higher the reliability.

[0081] Next, in step S17, the vehicle occupant detection device 10 (occupant determination unit 14) determines whether or not a person has been left behind in the vehicle based on the sensor signal from the radio wave sensor 20, similar to step S5.

[0082] Next, in step S18, the vehicle occupant detection device 10 (occupant determination unit 14) determines whether notification is necessary and the notification method based on the determination result of the abandoned vehicle determination process and the reliability of the abandoned vehicle determination process.

[0083] In step S18, the vehicle occupant detection device 10 (occupant determination unit 14) first performs frequency analysis on the sensor signal of the radio wave sensor 20 and determines whether notification is necessary based on whether the average signal intensity of the human respiratory frequency component (e.g., approximately 0.16 Hz to 1.00 Hz) (R1 region in Figures 1A to 1C) observed within a suitable distance range within the vehicle U (e.g., approximately 0.5 m to 1.00 m) is equal to or greater than the second threshold (where the second threshold is the signal intensity for distinguishing between a person and an object other than a person). If notification is necessary, the vehicle occupant detection device 10 (occupant determination unit 14) then determines the notification method to the user and the notification method to the area around the vehicle U based on the reliability of the abandoned vehicle determination process, as shown in Figure 6. The sensor signal of the radio wave sensor 20 obtained in step S14 is defined as having a reliability of 100%, for example.

[0084] As shown in Figure 6, the notification methods for the user and the area around the vehicle U are typically determined in a way that attracts the attention of the user and / or people around the vehicle U, with the greater the reliability of the abandoned vehicle detection process (i.e., the less vibration the vehicle U experiences). Figure 6 shows a data table as an example of a notification method, where the frequency of notifications to the user terminal increases or the volume of the warning sound increases as the reliability of the abandoned vehicle detection process increases.

[0085] Next, in step S19, the vehicle occupant detection device 10 (notification unit 16) notifies the user's terminal U1 and the area around the vehicle U that an unattended person has been left inside the vehicle, based on the notification pattern determined in step S18.

[0086] Thus, according to the modified vehicle occupant detection device 10, even if vibrations of the vehicle U caused by the user opening and closing the vehicle U doors remain when a person is left behind inside the vehicle, it is possible to inform the user of the possibility of such a situation occurring.

[0087] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. [Industrial applicability]

[0088] The vehicle occupant detection device described herein enables more accurate detection of persons left unattended inside a vehicle. [Explanation of Symbols]

[0089] 1. Abandoned item detection system 10. Vehicle occupant detection device 11 First acquisition part 12 Second acquisition part 13 Third acquisition part 14 Crew Determination Unit 15 Timing Control Unit 16 Hochi Department 20 Radio wave sensors 30 Vibration Sensor 40. Vehicle condition detection sensor 51 Warning sound generator 52 Warning light generator 53 Wireless communication equipment U Vehicle U1 User Terminal

Claims

1. A first acquisition unit is mounted on a vehicle and acquires sensor signals from a radio wave sensor that detects objects inside the vehicle, A second acquisition unit is mounted on the vehicle and acquires the sensor signal of a vibration sensor that detects vibrations of the vehicle, An occupant determination unit analyzes the current state of presence of objects inside the vehicle based on the sensor signal of the aforementioned radio wave sensor, and determines whether or not there are occupants inside the vehicle based on the analysis results. A detection timing control unit analyzes the current vibration state of the vehicle based on the sensor signal of the vibration sensor, permits the occupant determination unit to perform the determination when the vehicle is not vibrating, and disallows the occupant determination unit to perform the determination when the vehicle is vibrating. A notification unit that notifies the occupant determination unit of the determination result to the outside of the vehicle, Equipped with, The occupant determination unit performs frequency analysis of the sensor signal of the radio wave sensor and makes the determination regarding the presence or absence of an occupant in the vehicle based on the presence or absence of an object moving in a first specific frequency band within the vehicle. The detection timing control unit performs frequency analysis of the sensor signal of the vibration sensor and switches whether or not to allow / deny the occupant determination unit to perform the determination based on whether or not the vehicle is vibrating at a magnitude above a threshold in a second specific frequency band. The first specific frequency band and the second specific frequency band include at least a frequency band corresponding to the human respiratory frequency. Vehicle occupant detection device.

2. The vehicle is further equipped with a third acquisition unit that acquires sensor signals from a vehicle state detection sensor mounted on the vehicle, which detects changes in the state of the vehicle related to whether it is left unattended or not by the user. The detection timing control unit, based on the sensor signal of the vehicle state detection sensor, permits the occupant determination unit to perform the determination only when the vehicle is in an idle state. The vehicle occupant detection device according to claim 1.

3. The occupant determination unit performs the determination at the moment the vehicle switches from an idle state to an idle state. The vehicle occupant detection device according to claim 2.

4. The occupant determination unit periodically performs the determination while the vehicle is left unattended. The vehicle occupant detection device according to claim 2 or 3.

5. The notification unit uses a warning sound generator or a warning light generator mounted on the vehicle to notify the area around the vehicle of the result of the determination made by the occupant determination unit. A vehicle occupant detection device according to any one of claims 1 to 4.

6. The notification unit uses a wireless communication device mounted on the vehicle to notify the user of the result of the determination made by the occupant determination unit. A vehicle occupant detection device according to any one of claims 1 to 5.

7. The detection timing control unit, based on the sensor signal of the vibration sensor, if the vibration of the vehicle is detected to continue for a predetermined time, first causes the occupant determination unit to perform the determination, and then calculates the reliability of the determination made by the occupant determination unit according to the vibration state of the vehicle. The notification unit notifies the result of the determination made by the crew determination unit in a notification manner corresponding to the reliability of the determination made by the crew determination unit. A vehicle occupant detection device according to any one of claims 1 to 6.

8. The detection timing control unit switches between allowing or disallowing the occupant determination unit to perform the determination by controlling the operation of the radio wave sensor on or off, or by controlling the operation of acquiring a sensor signal from the radio wave sensor on or off. A vehicle occupant detection device according to any one of claims 1 to 7.

9. A first process for acquiring sensor signals from a radio wave sensor mounted on a vehicle and used to detect objects inside the vehicle, A second process for acquiring the sensor signal of a vibration sensor mounted on the vehicle and used to detect vibrations of the vehicle, A third process involves analyzing the presence status of objects inside the vehicle at the current time based on the sensor signal of the aforementioned radio wave sensor, and determining whether or not there are occupants inside the vehicle based on the analysis results. A fourth process analyzes the current vibration state of the vehicle based on the sensor signal of the vibration sensor, permits the execution of the determination in the third process if the vehicle is not vibrating, and denies the execution of the determination in the third process if the vehicle is vibrating. A fifth process which notifies the determination result of the third process to the outside of the vehicle, A vehicle occupant detection method having, In the third process, the frequency analysis of the sensor signal of the radio wave sensor is performed, and the determination regarding the presence or absence of occupants in the vehicle is made based on the presence or absence of an object moving in a first specific frequency band within the vehicle. In the fourth process, the frequency analysis of the sensor signal of the vibration sensor is performed, and depending on whether the vehicle is vibrating at a magnitude greater than or equal to a threshold in a second specific frequency band, permission / denial of the determination in the third process is switched. The first specific frequency band and the second specific frequency band include at least a frequency band corresponding to the human respiratory frequency. Vehicle occupant detection method.

10. On the computer, A first process for acquiring sensor signals from a radio wave sensor mounted on a vehicle and used to detect objects inside the vehicle, A second process for acquiring the sensor signal of a vibration sensor mounted on the vehicle and used to detect vibrations of the vehicle, A third process involves analyzing the presence status of objects inside the vehicle at the current time based on the sensor signal of the aforementioned radio wave sensor, and determining whether or not there are occupants inside the vehicle based on the analysis results. A fourth process analyzes the current vibration state of the vehicle based on the sensor signal of the vibration sensor, permits the execution of the determination in the third process if the vehicle is not vibrating, and denies the execution of the determination in the third process if the vehicle is vibrating. A fifth process which notifies the determination result of the third process to the outside of the vehicle, A vehicle occupant detection program that causes the execution of In the third process, the frequency analysis of the sensor signal of the radio wave sensor is performed, and the determination regarding the presence or absence of occupants in the vehicle is made based on the presence or absence of an object moving in a first specific frequency band within the vehicle. In the fourth process, the frequency analysis of the sensor signal of the vibration sensor is performed, and depending on whether the vehicle is vibrating at a magnitude greater than or equal to a threshold in a second specific frequency band, permission / denial of the determination in the third process is switched. The first specific frequency band and the second specific frequency band include at least a frequency band corresponding to the human respiratory frequency. Vehicle occupant detection program.

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